[System]
You are participating in Blender-Bench, a public benchmark where AI models complete the same Blender task.

Your result will be compared head-to-head with another model. Anyone on the internet can vote based on two equally important published views: a 2D rendered presentation and an interactive 3D scene exported to GLB. Treat neither view as optional; make the result clear and compelling in both.

Complete the request as well as you can. The benchmark does not prescribe a workflow or visual style; use whichever Blender techniques you consider appropriate. Make the important requirements evident in the published result, save a complete scene, and present the work clearly in every requested output.

The 2D presentation is rendered by the benchmark from your saved scene using Cycles at 1536 x 1536, 64 samples, denoising enabled, and GPU acceleration when available with a CPU fallback. It is the native-fidelity view of the Blender scene, so you may use Blender's full feature set. Preview and validate your materials, lighting, color management, and camera composition in Cycles, and do not rely on EEVEE-only effects for the final appearance.

The interactive 3D view is a best-effort GLB export containing geometry, compatible materials, the contestant camera, and supported lights. Because glTF cannot represent every Blender feature, native effects such as particles, hair or curves, volumes, simulations, and some procedural geometry may appear only in the 2D render. The benchmark may also generate a separate preview GLB by baking supported procedural material inputs to textures; this does not convert unsupported geometry or guarantee exact parity with Blender. When practical, keep the core form and scene readable in the 3D view while using the 2D presentation to show native Blender features faithfully.

## Harness Instructions

You are writing a single Python script for Blender 5.1 using the bpy API. The scene starts empty. Your script must build everything the user's prompt asks for.

You are building a real three-dimensional scene, and evaluators judge the whole scene and your final render side by side — an interactive 3D view and a benchmark-generated 360° camera orbit rendered in Cycles from your saved scene appear next to your presentation render, so forms that only read correctly from one angle will show. Build genuine 3D first, then present it well: before you finish, set up a camera and lighting to frame a single, well-composed presentation image of your result — a good scene that happens to have a well-placed camera and lights. The final benchmark capture overrides the scene render settings and renders in Cycles at 1536x1536, 64 samples, with denoising and GPU acceleration (CPU fallback). Preview and validate materials, lighting, color management, and composition in Cycles; do not rely on EEVEE-only effects. Use whatever Blender features best serve the result; a best-effort GLB export is also provided for interactive inspection, and features glTF cannot represent are not expected to survive it.

You get one attempt: the script runs once, headless, with no feedback and no chance to iterate, so write robust code. Reply with exactly one fenced Python code block containing the complete script and nothing else.

[User]
## Task

Complete the following Blender task:

<task>

A desk-mounted robotic arm with at least four articulated joints, posed mid-reach toward a small object on the desk — not a generic industrial catalog robot, but a refined experimental machine built from a combination of precision mechanical assemblies and selectively generative structural elements.

The arm’s main load-bearing struts are topology-optimized: organic metal members with smooth branching transitions, controlled lattice openings, and carefully shaped voids where material has been removed according to structural load. These parametric forms should appear only on the elongated structural links between joints. They must not continue into the base, rotary joints, wrist, actuators, or end effector. Each optimized strut should feel like a purpose-grown structural component installed within an otherwise conventional mechanical system.

All joints and connection points should be clearly assembled engineering components: machined cylindrical housings, bearings, rotary actuators, bolted flanges, hinge pins, compact gearboxes, brackets, covers, and replaceable interface plates. The base should be a clean, stable mechanical assembly with a visible rotating platform and mounting hardware. Avoid ornamental latticework in these areas. The contrast between the organic optimized struts and the precise modular joint assemblies is the design centerpiece.

Remove exposed corrugated pipes, aged tubing, rust, corrosion, or distressed materials. Cable routing should be minimal and controlled, using slim black electrical lines, internal channels, recessed cable guides, or compact articulated conduits integrated close to the structure. Nothing should appear improvised, draped, weathered, or steampunk.

Instead of heavy woven fabric, use a very restrained translucent technical membrane only where useful. Thin semi-transparent polymer panels or tensioned mesh can span selected openings within the optimized struts, lightly revealing the structure beneath. The material should resemble clear reinforced film, translucent TPU, or fine architectural mesh rather than carbon fiber or ballistic cloth. It should feel protective and lightweight, not decorative. This membrane may also be omitted from some segments so the metal structure remains visually dominant.

The manipulator should not use a three-clawed radial gripper. Replace it with a compact two-finger parallel gripper or a refined adaptive pincer mechanism. The fingers should be mechanically designed from solid machined components with small replaceable contact pads, visible pivots, and believable actuation. Do not use topology-optimized lattice geometry on the fingers. The end effector should look precise, stable, and suitable for picking up small desk objects rather than aggressive or creature-like.

The mechanics must remain fully believable: visible rotational axes at every joint, plausible actuator placement, clear mechanical interfaces between segments, realistic joint limits, and sensible tapering from the heavy base to the smaller wrist and gripper. The pose must respect the joint layout, with no intersecting parts, impossible bends, unsupported structures, or decorative mechanisms that do not explain their function.

Present the arm in a clean contemporary design studio or robotics lab, reaching toward a small machined object on a desk. Use premium product-design lighting, a neutral background, crisp material separation, and enough detail to show how the arm is assembled. The final design should feel like a functional research prototype combining generative engineering with disciplined industrial design.

</task>

[System]
You are participating in Blender-Bench, a public benchmark where AI models complete the same Blender task.

Your result will be compared head-to-head with another model. Anyone on the internet can vote based on two equally important published views: a 2D rendered presentation and an interactive 3D scene exported to GLB. Treat neither view as optional; make the result clear and compelling in both.

Complete the request as well as you can. The benchmark does not prescribe a workflow or visual style; use whichever Blender techniques you consider appropriate. Make the important requirements evident in the published result, save a complete scene, and present the work clearly in every requested output.

The 2D presentation is rendered by the benchmark from your saved scene using Cycles at 1536 x 1536, 64 samples, denoising enabled, and GPU acceleration when available with a CPU fallback. It is the native-fidelity view of the Blender scene, so you may use Blender's full feature set. Preview and validate your materials, lighting, color management, and camera composition in Cycles, and do not rely on EEVEE-only effects for the final appearance.

The interactive 3D view is a best-effort GLB export containing geometry, compatible materials, the contestant camera, and supported lights. Because glTF cannot represent every Blender feature, native effects such as particles, hair or curves, volumes, simulations, and some procedural geometry may appear only in the 2D render. The benchmark may also generate a separate preview GLB by baking supported procedural material inputs to textures; this does not convert unsupported geometry or guarantee exact parity with Blender. When practical, keep the core form and scene readable in the 3D view while using the 2D presentation to show native Blender features faithfully.

## Harness Instructions

You are writing a single Python script for Blender 5.1 using the bpy API. The scene starts empty. Your script must build everything the user's prompt asks for.

You are building a real three-dimensional scene, and evaluators judge the whole scene and your final render side by side — an interactive 3D view and a benchmark-generated 360° camera orbit rendered in Cycles from your saved scene appear next to your presentation render, so forms that only read correctly from one angle will show. Build genuine 3D first, then present it well: before you finish, set up a camera and lighting to frame a single, well-composed presentation image of your result — a good scene that happens to have a well-placed camera and lights. The final benchmark capture overrides the scene render settings and renders in Cycles at 1536x1536, 64 samples, with denoising and GPU acceleration (CPU fallback). Preview and validate materials, lighting, color management, and composition in Cycles; do not rely on EEVEE-only effects. Use whatever Blender features best serve the result; a best-effort GLB export is also provided for interactive inspection, and features glTF cannot represent are not expected to survive it.

You get one attempt: the script runs once, headless, with no feedback and no chance to iterate, so write robust code. Reply with exactly one fenced Python code block containing the complete script and nothing else.

[User]
## Task

Complete the following Blender task:

<task>

A desk-mounted robotic arm with at least four articulated joints, posed mid-reach toward a small object on the desk — not a generic industrial catalog robot, but a refined experimental machine built from a combination of precision mechanical assemblies and selectively generative structural elements.

The arm’s main load-bearing struts are topology-optimized: organic metal members with smooth branching transitions, controlled lattice openings, and carefully shaped voids where material has been removed according to structural load. These parametric forms should appear only on the elongated structural links between joints. They must not continue into the base, rotary joints, wrist, actuators, or end effector. Each optimized strut should feel like a purpose-grown structural component installed within an otherwise conventional mechanical system.

All joints and connection points should be clearly assembled engineering components: machined cylindrical housings, bearings, rotary actuators, bolted flanges, hinge pins, compact gearboxes, brackets, covers, and replaceable interface plates. The base should be a clean, stable mechanical assembly with a visible rotating platform and mounting hardware. Avoid ornamental latticework in these areas. The contrast between the organic optimized struts and the precise modular joint assemblies is the design centerpiece.

Remove exposed corrugated pipes, aged tubing, rust, corrosion, or distressed materials. Cable routing should be minimal and controlled, using slim black electrical lines, internal channels, recessed cable guides, or compact articulated conduits integrated close to the structure. Nothing should appear improvised, draped, weathered, or steampunk.

Instead of heavy woven fabric, use a very restrained translucent technical membrane only where useful. Thin semi-transparent polymer panels or tensioned mesh can span selected openings within the optimized struts, lightly revealing the structure beneath. The material should resemble clear reinforced film, translucent TPU, or fine architectural mesh rather than carbon fiber or ballistic cloth. It should feel protective and lightweight, not decorative. This membrane may also be omitted from some segments so the metal structure remains visually dominant.

The manipulator should not use a three-clawed radial gripper. Replace it with a compact two-finger parallel gripper or a refined adaptive pincer mechanism. The fingers should be mechanically designed from solid machined components with small replaceable contact pads, visible pivots, and believable actuation. Do not use topology-optimized lattice geometry on the fingers. The end effector should look precise, stable, and suitable for picking up small desk objects rather than aggressive or creature-like.

The mechanics must remain fully believable: visible rotational axes at every joint, plausible actuator placement, clear mechanical interfaces between segments, realistic joint limits, and sensible tapering from the heavy base to the smaller wrist and gripper. The pose must respect the joint layout, with no intersecting parts, impossible bends, unsupported structures, or decorative mechanisms that do not explain their function.

Present the arm in a clean contemporary design studio or robotics lab, reaching toward a small machined object on a desk. Use premium product-design lighting, a neutral background, crisp material separation, and enough detail to show how the arm is assembled. The final design should feel like a functional research prototype combining generative engineering with disciplined industrial design.

</task>

payment=(self "https://checkout.stripe.com" "https://connect-js.stripe.com" "https://js.stripe.com" "https://*.js.stripe.com" "https://hooks.stripe.com")

{"id":"gen-1784307566-cpONqozBMbi3oHEJkw1M","object":"chat.completion","created":1784307566,"model":"moonshotai/kimi-k3","provider":"Moonshot AI","system_fingerprint":"fpv0_15e428e8","service_tier":null,"choices":[{"index":0,"logprobs":null,"finish_reason":"stop","native_finish_reason":"stop","message":{"role":"assistant","content":"```python\nimport bpy, math, os\nfrom math import sin, cos, pi, radians, atan2\nfrom mathutils import Vector, Matrix\n\n# ============================================================\n# SCENE RESET / RENDER SETUP\n# ============================================================\nbpy.ops.object.select_all(action='SELECT')\nbpy.ops.object.delete(use_global=False)\nscene = bpy.context.scene\nscene.render.engine = 'CYCLES'\nscene.cycles.samples = 64\nscene.cycles.use_denoising = True\nscene.render.resolution_x = 1536\nscene.render.resolution_y = 1536\nscene.render.resolution_percentage = 100\nscene.render.image_settings.file_format = 'PNG'\nscene.unit_settings.system = 'METRIC'\ntry:\n    scene.view_settings.look = 'AgX - Medium High Contrast'\nexcept Exception:\n    pass\n\n# ============================================================\n# MATERIALS\n# ============================================================\ndef mat_principled(name, color, metallic=0.0, rough=0.4, transmission=0.0,\n                   ior=1.45, emission=None, estr=0.0, coat=0.0):\n    m = bpy.data.materials.new(name); m.use_nodes = True\n    bs = m.node_tree.nodes['Principled BSDF']\n    bs.inputs['Base Color'].default_value = (*color, 1.0)\n    bs.inputs['Metallic'].default_value = metallic\n    bs.inputs['Roughness'].default_value = rough\n    if transmission > 0:\n        bs.inputs['Transmission Weight'].default_value = transmission\n        bs.inputs['IOR'].default_value = ior\n    if coat > 0:\n        bs.inputs['Coat Weight'].default_value = coat\n    if emission is not None:\n        bs.inputs['Emission Color'].default_value = (*emission, 1.0)\n        bs.inputs['Emission Strength'].default_value = estr\n    return m\n\ntitanium = mat_principled('Strut_Titanium', (0.60, 0.61, 0.64), 1.0, 0.34)\nalu      = mat_principled('Machined_Aluminum', (0.78, 0.79, 0.81), 1.0, 0.22)\nalu_dark = mat_principled('Anodized_Dark', (0.15, 0.16, 0.18), 0.9, 0.32)\nsteel    = mat_principled('Steel', (0.42, 0.43, 0.46), 1.0, 0.18)\naccent   = mat_principled('Accent_Orange', (0.82, 0.26, 0.045), 0.85, 0.30)\ncablem   = mat_principled('Cable_Black', (0.012, 0.013, 0.015), 0.0, 0.55)\npadm     = mat_principled('Pad_Urethane', (0.85, 0.38, 0.06), 0.0, 0.5)\ndeskm    = mat_principled('Desk_Laminate', (0.80, 0.79, 0.76), 0.0, 0.38)\nfloorm   = mat_principled('Studio_Floor', (0.66, 0.66, 0.68), 0.0, 0.58)\nboxm     = mat_principled('Controller_Housing', (0.05, 0.05, 0.06), 0.3, 0.42)\nledg     = mat_principled('LED_Green', (0.02, 0.08, 0.03), 0, 0.4, emission=(0.15, 1.0, 0.35), estr=9.0)\nleda     = mat_principled('LED_Amber', (0.08, 0.04, 0.01), 0, 0.4, emission=(1.0, 0.5, 0.1), estr=9.0)\n\n# translucent technical membrane (clear reinforced film / TPU)\nmemb = mat_principled('Membrane_TPU', (0.72, 0.78, 0.82), 0.0, 0.34,\n                      transmission=0.9, ior=1.38, coat=0.25)\n_nt = memb.node_tree\n_bs = _nt.nodes['Principled BSDF']\n_noise = _nt.nodes.new('ShaderNodeTexNoise')\n_noise.inputs['Scale'].default_value = 320.0\n_noise.inputs['Detail'].default_value = 2.0\n_bump = _nt.nodes.new('ShaderNodeBump')\n_bump.inputs['Strength'].default_value = 0.12\n_bump.inputs['Distance'].default_value = 0.00025\n_nt.links.new(_noise.outputs['Fac'], _bump.inputs['Height'])\n_nt.links.new(_bump.outputs['Normal'], _bs.inputs['Normal'])\n\n# ============================================================\n# GEOMETRY HELPERS\n# ============================================================\ndef frame_from_axis(axis):\n    z = Vector(axis).normalized()\n    t = Vector((0, 0, 1)) if abs(z.z) < 0.95 else Vector((1, 0, 0))\n    x = z.cross(t).normalized()\n    y = z.cross(x).normalized()\n    return x, y, z\n\ndef set_frame(obj, x, y, z, loc):\n    M = Matrix((x, y, z)).transposed().to_4x4()\n    M.translation = Vector(loc)\n    obj.matrix_world = M\n\ndef assign(o, mat):\n    if mat: o.data.materials.append(mat)\n\ndef cyl(name, r, depth, loc, axis=(0, 0, 1), mat=None, verts=48, bevel=0.0, smooth=True):\n    bpy.ops.mesh.primitive_cylinder_add(vertices=verts, radius=r, depth=depth, location=loc)\n    o = bpy.context.active_object; o.name = name\n    x, y, z = frame_from_axis(axis)\n    set_frame(o, x, y, z, loc)\n    assign(o, mat)\n    if smooth:\n        for p in o.data.polygons:\n            p.use_smooth = (len(p.vertices) == 4)\n    if bevel > 0:\n        m = o.modifiers.new('bev', 'BEVEL'); m.width = bevel; m.segments = 3; m.limit_method = 'ANGLE'\n    return o\n\ndef box(name, dims, loc, frame=None, mat=None, bevel=0.0):\n    bpy.ops.mesh.primitive_cube_add(size=1, location=loc)\n    o = bpy.context.active_object; o.name = name\n    o.dimensions = dims\n    bpy.ops.object.transform_apply(location=False, rotation=False, scale=True)\n    if frame:\n        set_frame(o, frame[0], frame[1], frame[2], loc)\n    assign(o, mat)\n    if bevel > 0:\n        m = o.modifiers.new('bev', 'BEVEL'); m.width = bevel; m.segments = 3; m.limit_method = 'ANGLE'\n    return o\n\ndef torus(name, R, r, loc, axis=(0, 0, 1), mat=None):\n    bpy.ops.mesh.primitive_torus_add(major_radius=R, minor_radius=r,\n                                     major_segments=48, minor_segments=12, location=loc)\n    o = bpy.context.active_object; o.name = name\n    x, y, z = frame_from_axis(axis)\n    set_frame(o, x, y, z, loc)\n    assign(o, mat)\n    for p in o.data.polygons: p.use_smooth = True\n    return o\n\ndef bolt(name, p, axis, r, h, mat=steel, washer=True):\n    a = Vector(axis).normalized(); P = Vector(p)\n    if washer:\n        cyl(name + '_w', r * 1.6, h * 0.30, P + a * (h * 0.15), axis, mat, verts=24)\n    cyl(name + '_h', r, h, P + a * (h * 0.30 + h * 0.5), axis, mat, verts=6, smooth=False)\n\ndef bolt_ring(name, center, axis, ring_r, n, r, h, mat=steel, phase=0.0):\n    x, y, z = frame_from_axis(axis)\n    C = Vector(center)\n    for k in range(n):\n        a = phase + 2 * pi * k / n\n        p = C + x * (ring_r * cos(a)) + y * (ring_r * sin(a))\n        bolt('%s_%d' % (name, k), p, axis, r, h, mat, washer=False)\n\ndef rod(name, p1, p2, r, mat=steel, verts=12):\n    d = Vector(p2) - Vector(p1)\n    return cyl(name, r, d.length, (Vector(p1) + Vector(p2)) / 2, axis=d.normalized(),\n               mat=mat, verts=verts)\n\ndef cable(name, pts, r, mat=cablem):\n    cu = bpy.data.curves.new(name, 'CURVE'); cu.dimensions = '3D'\n    cu.resolution_u = 16; cu.bevel_depth = r; cu.bevel_resolution = 3\n    sp = cu.splines.new('BEZIER'); sp.bezier_points.add(len(pts) - 1)\n    for bp, co in zip(sp.bezier_points, pts):\n        bp.co = co; bp.handle_left_type = 'AUTO'; bp.handle_right_type = 'AUTO'\n    ob = bpy.data.objects.new(name, cu)\n    bpy.context.scene.collection.objects.link(ob)\n    assign(ob, mat)\n    return ob\n\ndef led(name, p, axis, mat, r=0.0022):\n    a = Vector(axis).normalized(); P = Vector(p)\n    cyl(name + '_bz', r * 1.7, 0.0018, P - a * 0.0004, axis, alu_dark, verts=24)\n    cyl(name + '_c', r, 0.0014, P + a * 0.0009, axis, mat, verts=16)\n\ndef look_at(ob, target):\n    d = Vector(target) - ob.location\n    ob.rotation_euler = d.to_track_quat('-Z', 'Y').to_euler()\n\n# ============================================================\n# TOPOLOGY-OPTIMIZED STRUT BUILDER (skin + subsurf, organic)\n# ============================================================\ndef optimized_strut(name, A, B, dA, dB, rA, rB, bend, n, mat):\n    A = Vector(A); B = Vector(B)\n    u = (B - A); L = u.length; u.normalize()\n    v = Vector((0.0, 1.0, 0.0))\n    w = u.cross(v).normalized()\n    v = w.cross(u).normalized()\n    def prof(t): return 0.60 + 0.55 * (abs(cos(pi * t)) ** 0.75)\n    def hfun(t): return (dA + (dB - dA) * t) * 0.5 * prof(t)\n    def rfun(t): return (rA + (rB - rA) * t) * (1.30 - 0.50 * sin(pi * t))\n    def center(t): return A + u * (L * t) + w * (bend * sin(pi * t))\n    verts = []; edges = []\n    for i in range(n + 1):\n        t = i / n; C = center(t); h = hfun(t)\n        verts.append(C + w * h); verts.append(C - w * h)\n    for i in range(n):\n        a = 2 * i\n        edges.append((a, a + 2)); edges.append((a + 1, a + 3))\n    edges.append((0, 1)); edges.append((2 * n, 2 * n + 1))\n    diag = set()\n    for i in range(n):\n        a = 2 * i\n        diag.add((a, a + 3) if i % 2 == 0 else (a + 1, a + 2))\n    mid = n // 2; a = 2 * mid\n    diag.add((a, a + 3)); diag.add((a + 1, a + 2))   # X-braced middle bay\n    for e in diag:\n        edges.append((min(e), max(e)))\n    radii = []\n    for i in range(n + 1):\n        r = rfun(i / n); radii += [r, r]\n    me = bpy.data.meshes.new(name)\n    me.from_pydata([tuple(p) for p in verts], edges, [])\n    ob = bpy.data.objects.new(name, me)\n    bpy.context.scene.collection.objects.link(ob)\n    sk = ob.modifiers.new('Skin', 'SKIN')\n    bpy.context.view_layer.update()\n    sv = me.skin_vertices[0].data\n    for i, d in enumerate(sv):\n        d.radius = (radii[i], radii[i])\n    sv[0].use_root = True\n    bpy.ops.object.select_all(action='DESELECT')\n    ob.select_set(True); bpy.context.view_layer.objects.active = ob\n    bpy.ops.object.modifier_apply(modifier=sk.name)\n    for p in me.polygons: p.use_smooth = True\n    sub = ob.modifiers.new('Sub', 'SUBSURF'); sub.levels = 2; sub.render_levels = 2\n    me.materials.append(mat)\n    tops = [verts[2 * i] for i in range(n + 1)]\n    bots = [verts[2 * i + 1] for i in range(n + 1)]\n    return dict(obj=ob, u=u, v=v, w=w, A=A, L=L, n=n, tops=tops, bots=bots,\n                center=center, hfun=hfun, rfun=rfun)\n\ndef membrane(name, st, bay, mat, bow=0.0028, nx=8, ny=8, inset=0.07):\n    tops = st['tops']; bots = st['bots']; nrm = Vector(st['v'])\n    c00 = bots[bay]; c10 = bots[bay + 1]; c11 = tops[bay + 1]; c01 = tops[bay]\n    C = (c00 + c10 + c11 + c01) / 4\n    P = [c + (C - c) * inset for c in (c00, c10, c11, c01)]\n    verts = []; faces = []\n    for j in range(ny + 1):\n        s = j / ny\n        for i in range(nx + 1):\n            r = i / nx\n            p = (1 - r) * (1 - s) * P[0] + r * (1 - s) * P[1] + r * s * P[2] + (1 - r) * s * P[3]\n            p = p + nrm * (bow * sin(pi * r) * sin(pi * s))\n            verts.append(tuple(p))\n    for j in range(ny):\n        for i in range(nx):\n            a = j * (nx + 1) + i\n            faces.append((a, a + 1, a + nx + 2, a + nx + 1))\n    me = bpy.data.meshes.new(name)\n    me.from_pydata(verts, [], faces)\n    ob = bpy.data.objects.new(name, me)\n    bpy.context.scene.collection.objects.link(ob)\n    for p in me.polygons: p.use_smooth = True\n    sol = ob.modifiers.new('Solid', 'SOLIDIFY'); sol.thickness = 0.0011; sol.offset = 0.0\n    me.materials.append(mat)\n    return ob\n\ndef cable_clip(name, st, t, off, mat=alu_dark):\n    u = st['u']; v = st['v']; w = st['w']\n    C = st['center'](t); surf = st['hfun'](t) + st['rfun'](t)\n    depth = off - surf + 0.006\n    loc = C - w * ((surf + off) / 2)\n    return box(name, (0.012, 0.020, depth), loc, frame=(u, v, w), mat=mat, bevel=0.002)\n\ndef scpts(st, off, ts, voff):\n    return [st['center'](t) - st['w'] * off + st['v'] * voff for t in ts]\n\n# ============================================================\n# KINEMATICS (joint layout)\n# ============================================================\nS = Vector((0.0, 0.0, 0.165))                       # shoulder (J2)\na1 = radians(48.0)\nu1 = Vector((sin(a1), 0, cos(a1)))\nL1 = 0.30\nE = S + u1 * L1                                     # elbow (J3)\nW = Vector((0.425, 0.0, 0.165))                     # wrist pitch (J4)\n_d = W - E; L2 = _d.length; u2 = _d / L2\nth2 = atan2(u2.z, u2.x); th3 = th2 - radians(28.0)\nu3 = Vector((cos(th3), 0, sin(th3)))                # tool axis\nv = Vector((0, 1, 0))\nw1 = u1.cross(v).normalized()\nw2 = u2.cross(v).normalized()\nw3 = u3.cross(v).normalized()\nF = W + u3 * 0.130                                  # fingertip reference\nobj_x = F.x + u3.x * 0.018\n\n# ============================================================\n# BASE ASSEMBLY (J1 rotary platform)\n# ============================================================\nbox('BasePlate', (0.17, 0.17, 0.014), (0, 0, 0.007), mat=alu_dark, bevel=0.008)\nfor sx in (-1, 1):\n    for sy in (-1, 1):\n        bolt('BaseBolt', (0.072 * sx, 0.072 * sy, 0.014), (0, 0, 1), 0.0045, 0.005)\ncyl('BaseLower', 0.062, 0.032, (0, 0, 0.030), mat=alu, bevel=0.004)\ncyl('BaseBearingRing', 0.056, 0.012, (0, 0, 0.052), mat=alu_dark, bevel=0.002)\ncyl('BaseAccentRing', 0.0568, 0.0022, (0, 0, 0.0575), mat=accent)\ncyl('Turret', 0.050, 0.036, (0, 0, 0.076), mat=alu, bevel=0.004)\ncyl('TurretTopPlate', 0.055, 0.008, (0, 0, 0.098), mat=alu_dark, bevel=0.002)\nbolt_ring('TurretBolt', (0, 0, 0.102), (0, 0, 1), 0.043, 6, 0.0028, 0.0035)\nled('TurretLED', (0, -0.0495, 0.072), (0, -1, 0), ledg)\nbox('TurretTick', (0.005, 0.0014, 0.006), (0, -0.0498, 0.085), mat=accent, bevel=0.0005)\nbox('BaseNamePlate', (0.05, 0.002, 0.010), (0, -0.0856, 0.007), mat=alu, bevel=0.0006)\n# shoulder cheeks\nfor s in (-1, 1):\n    box('Cheek', (0.060, 0.014, 0.089), (-0.005, 0.043 * s, 0.1455), mat=alu, bevel=0.006)\n    bolt('CheekBoltA', (-0.022, 0.0505 * s, 0.122), (0, s, 0), 0.0028, 0.0035, washer=False)\n    bolt('CheekBoltB', (0.014, 0.0505 * s, 0.122), (0, s, 0), 0.0028, 0.0035, washer=False)\n    bolt('CheekBoltC', (-0.022, 0.043 * s, 0.103), (0, 0, 1), 0.0025, 0.003, washer=False)\n    box('StopTab', (0.014, 0.010, 0.018), (-0.032, 0.030 * s, 0.148), mat=alu_dark, bevel=0.002)\n# J2 shaft / gearbox / motor\ncyl('J2_Pin', 0.0105, 0.19, (0, 0, 0.165), axis=(0, 1, 0), mat=steel)\nfor s in (-1, 1):\n    cyl('J2_Thrust', 0.0135, 0.003, (0, 0.0305 * s, 0.165), axis=(0, 1, 0), mat=steel)\ncyl('J2_GearFlange', 0.034, 0.003, (0, 0.0515, 0.165), axis=(0, 1, 0), mat=alu_dark)\ncyl('J2_Gearbox', 0.032, 0.024, (0, 0.0645, 0.165), axis=(0, 1, 0), mat=alu, bevel=0.004)\ncyl('J2_GearCap', 0.020, 0.007, (0, 0.080, 0.165), axis=(0, 1, 0), mat=alu_dark, bevel=0.002)\ncyl('J2_GearCollar', 0.013, 0.006, (0, 0.0855, 0.165), axis=(0, 1, 0), mat=steel)\nbolt('J2_GearHex', (0, 0.0885, 0.165), (0, 1, 0), 0.0045, 0.004, washer=False)\nbolt_ring('J2_GearBolt', (0, 0.077, 0.165), (0, 1, 0), 0.024, 4, 0.0022, 0.003)\ncyl('J2_MotorFlange', 0.028, 0.005, (0, -0.053, 0.165), axis=(0, 1, 0), mat=alu_dark)\ncyl('J2_Motor', 0.024, 0.048, (0, -0.077, 0.165), axis=(0, 1, 0), mat=alu, bevel=0.004)\ncyl('J2_MotorCap', 0.0245, 0.006, (0, -0.104, 0.165), axis=(0, 1, 0), mat=alu_dark, bevel=0.002)\ncyl('J2_MotorCollar', 0.011, 0.005, (0, -0.1085, 0.165), axis=(0, 1, 0), mat=steel)\ntorus('J2_AccentA', 0.0248, 0.0014, (0, -0.100, 0.165), axis=(0, 1, 0), mat=accent)\n\n# ============================================================\n# LINK 1 : hubs, fork, optimized strut\n# ============================================================\ncyl('L1_RootHub', 0.026, 0.062, S + u1 * 0.008, axis=u1, mat=alu, bevel=0.004)\ncyl('L1_RootCollar', 0.029, 0.005, S + u1 * 0.040, axis=u1, mat=alu_dark)\nbolt_ring('L1_RootBolt', S + u1 * 0.0435, u1, 0.021, 4, 0.002, 0.0028)\ncyl('L1_EndCollar', 0.020, 0.050, E - u1 * 0.028, axis=u1, mat=alu, bevel=0.003)\nbolt_ring('L1_EndBolt', E - u1 * 0.052, -u1, 0.014, 4, 0.0018, 0.0025)\nfor s in (-1, 1):\n    box('L1_Fork', (0.052, 0.010, 0.046), E - u1 * 0.008 + v * (0.030 * s),\n        frame=(u1, v, w1), mat=alu, bevel=0.005)\ns1 = optimized_strut('Strut_Upper', S + u1 * 0.036, E - u1 * 0.040,\n                     0.080, 0.056, 0.0115, 0.0085, -0.012, 12, titanium)\nmembrane('Memb_U1', s1, 3, memb)\nmembrane('Memb_U2', s1, 8, memb)\n\n# ============================================================\n# ELBOW JOINT (J3)\n# ============================================================\ncyl('J3_Pin', 0.007, 0.10, E, axis=(0, 1, 0), mat=steel)\nfor s in (-1, 1):\n    cyl('J3_Thrust', 0.0105, 0.0025, E + v * (0.0215 * s), axis=(0, 1, 0), mat=steel)\ncyl('J3_GearFlange', 0.024, 0.004, E + v * 0.0365, axis=(0, 1, 0), mat=alu_dark)\ncyl('J3_Gearbox', 0.022, 0.020, E + v * 0.049, axis=(0, 1, 0), mat=alu, bevel=0.003)\ncyl('J3_GearCap', 0.014, 0.006, E + v * 0.062, axis=(0, 1, 0), mat=alu_dark)\ncyl('J3_GearCollar', 0.009, 0.005, E + v * 0.067, axis=(0, 1, 0), mat=steel)\nbolt('J3_GearHex', E + v * 0.070, (0, 1, 0), 0.0035, 0.0035, washer=False)\nbolt_ring('J3_GearBolt', E + v * 0.0595, (0, 1, 0), 0.016, 4, 0.0018, 0.0025)\ncyl('J3_MotorFlange', 0.021, 0.004, E - v * 0.0365, axis=(0, 1, 0), mat=alu_dark)\ncyl('J3_Motor', 0.019, 0.028, E - v * 0.052, axis=(0, 1, 0), mat=alu, bevel=0.003)\ncyl('J3_MotorCap', 0.0195, 0.005, E - v * 0.0685, axis=(0, 1, 0), mat=alu_dark)\ncyl('J3_MotorCollar', 0.009, 0.004, E - v * 0.0725, axis=(0, 1, 0), mat=steel)\nled('J3_LED', E + Vector((0, -0.0718, 0.006)), (0, -1, 0), leda, r=0.0018)\ntorus('J3_Accent', 0.0198, 0.0012, E - v * 0.065, axis=(0, 1, 0), mat=accent)\n\n# ============================================================\n# LINK 2 : eye, optimized strut, end fork\n# ============================================================\nbox('L2_RootEye', (0.056, 0.036, 0.040), E + u2 * 0.012, frame=(u2, v, w2), mat=alu, bevel=0.012)\ncyl('L2_RootCollar', 0.0195, 0.006, E + u2 * 0.041, axis=u2, mat=alu_dark)\nbolt_ring('L2_RootBolt', E + u2 * 0.0445, u2, 0.0135, 4, 0.0018, 0.0025)\ncyl('L2_EndCollar', 0.015, 0.050, W - u2 * 0.028, axis=u2, mat=alu, bevel=0.003)\nbolt_ring('L2_EndBolt', W - u2 * 0.052, -u2, 0.010, 4, 0.0015, 0.0022)\nfor s in (-1, 1):\n    box('L2_Fork', (0.046, 0.008, 0.034), W - u2 * 0.006 + v * (0.022 * s),\n        frame=(u2, v, w2), mat=alu, bevel=0.004)\ns2 = optimized_strut('Strut_Fore', E + u2 * 0.038, W - u2 * 0.034,\n                     0.052, 0.034, 0.0080, 0.0058, -0.010, 11, titanium)\nmembrane('Memb_F1', s2, 4, memb)\n\n# ============================================================\n# WRIST (J4 pitch + J5 roll) AND PARALLEL GRIPPER\n# ============================================================\ncyl('J4_Pin', 0.005, 0.072, W, axis=(0, 1, 0), mat=steel)\nfor s in (-1, 1):\n    cyl('J4_Thrust', 0.0085, 0.0015, W + v * (0.0175 * s), axis=(0, 1, 0), mat=steel)\ncyl('WristBlock', 0.016, 0.034, W, axis=(0, 1, 0), mat=alu, bevel=0.003)\ncyl('J4_EncFlange', 0.0145, 0.003, W + v * 0.0275, axis=(0, 1, 0), mat=alu_dark)\ncyl('J4_Encoder', 0.0135, 0.010, W + v * 0.033, axis=(0, 1, 0), mat=alu, bevel=0.002)\ncyl('J4_EncCap', 0.010, 0.005, W + v * 0.0405, axis=(0, 1, 0), mat=alu_dark)\ncyl('J4_EncCollar', 0.006, 0.004, W + v * 0.044, axis=(0, 1, 0), mat=steel)\ncyl('J4_MotorFlange', 0.014, 0.003, W - v * 0.0275, axis=(0, 1, 0), mat=alu_dark)\ncyl('J4_Motor', 0.0125, 0.028, W - v * 0.0425, axis=(0, 1, 0), mat=alu, bevel=0.002)\ncyl('J4_MotorCap', 0.013, 0.005, W - v * 0.059, axis=(0, 1, 0), mat=alu_dark)\nled('J4_LED', W + Vector((0, -0.0622, 0.004)), (0, -1, 0), ledg, r=0.0016)\n# J5 roll actuator + tool flange\ncyl('J5_Actuator', 0.0145, 0.034, W + u3 * 0.019, axis=u3, mat=alu, bevel=0.003)\ntorus('J5_Accent', 0.0148, 0.0016, W + u3 * 0.037, axis=u3, mat=accent)\ncyl('ToolFlange', 0.019, 0.006, W + u3 * 0.041, axis=u3, mat=alu_dark, bevel=0.0015)\nbolt_ring('ToolBolt', W + u3 * 0.0445, u3, 0.0135, 4, 0.002, 0.0028)\n# gripper body\nbox('GripperBody', (0.036, 0.040, 0.024), W + u3 * 0.065, frame=(u3, v, w3), mat=alu_dark, bevel=0.005)\nbox('GripperFrontPlate', (0.004, 0.036, 0.020), W + u3 * 0.0845, frame=(u3, v, w3), mat=alu, bevel=0.001)\nbolt_ring('GripPlateBolt', W + u3 * 0.0868, u3, 0.011, 4, 0.0016, 0.0022)\nled('GripLED', W + u3 * 0.060 - v * 0.0206, (0, -1, 0), leda, r=0.0015)\n# servo on top\ncyl('GripServoFlange', 0.010, 0.003, W + u3 * 0.058 + w3 * 0.0125, axis=w3, mat=alu_dark)\ncyl('GripServo', 0.0085, 0.018, W + u3 * 0.058 + w3 * 0.021, axis=w3, mat=alu, bevel=0.002)\ncyl('GripServoCap', 0.0088, 0.004, W + u3 * 0.058 + w3 * 0.031, axis=w3, mat=alu_dark)\n# rails + end plates\nfor s in (-1, 1):\n    cyl('Rail', 0.0028, 0.045, W + u3 * 0.092 + w3 * (0.0065 * s), axis=(0, 1, 0), mat=steel, verts=20)\n    box('RailEndPlate', (0.026, 0.004, 0.018), W + u3 * 0.092 + v * (0.0225 * s),\n        frame=(u3, v, w3), mat=alu, bevel=0.002)\n    # carriage, pivot, finger, pad\n    box('Carriage', (0.014, 0.009, 0.016), W + u3 * 0.095 + v * (0.017 * s),\n        frame=(u3, v, w3), mat=alu, bevel=0.002)\n    cyl('FingerPivot', 0.0032, 0.012, W + u3 * 0.092 + v * (0.017 * s), axis=(0, 1, 0), mat=steel, verts=20)\n    cyl('PivotCap', 0.0048, 0.0015, W + u3 * 0.092 + v * (0.0232 * s), axis=(0, 1, 0), mat=alu_dark, verts=20)\n    box('Finger', (0.046, 0.0045, 0.012), W + u3 * 0.107 + v * (0.017 * s),\n        frame=(u3, v, w3), mat=alu, bevel=0.0015)\n    box('Pad', (0.012, 0.0030, 0.010), W + u3 * 0.124 + v * (0.01525 * s),\n        frame=(u3, v, w3), mat=padm, bevel=0.001)\n    for ds, dw in ((0.120, 0.003), (0.128, -0.003)):\n        bolt('PadBolt', W + u3 * ds + w3 * dw + v * (0.0193 * s), (0, s, 0), 0.0016, 0.002, washer=False)\n    rod('LinkRod', W + u3 * 0.058 + w3 * 0.0305,\n        W + u3 * 0.100 + v * (0.017 * s) + w3 * 0.0075, 0.0016)\n\n# ============================================================\n# CONTROLLED CABLE ROUTING (slim black lines + clips)\n# ============================================================\ncyl('GrommetA', 0.005, 0.006, (-0.022, -0.033, 0.100), mat=alu_dark, verts=20)\ncable('Cable_J2Motor', [(0, -0.107, 0.156), (-0.005, -0.094, 0.126),\n                        (-0.014, -0.058, 0.106), (-0.022, -0.034, 0.102)], 0.0020)\ncyl('GrommetB', 0.005, 0.006, (0.012, -0.026, 0.100), mat=alu_dark, verts=20)\npts = [(0.012, -0.026, 0.104)]\npts += scpts(s1, 0.072, [0.10, 0.28, 0.52, 0.74], -0.026)\npts += [s1['center'](0.92) - s1['w'] * 0.060 + s1['v'] * (-0.05),\n        Vector((E.x, -0.069, E.z + 0.004))]\ncable('Cable_Link1', pts, 0.0022)\nfor t in (0.28, 0.52, 0.74):\n    cable_clip('Clip1', s1, t, 0.072)\npts = [Vector((E.x + 0.003, -0.069, E.z + 0.008))]\npts += scpts(s2, 0.050, [0.15, 0.40, 0.65, 0.88], -0.024)\npts += [Vector((W.x, -0.056, W.z + 0.004))]\ncable('Cable_Link2', pts, 0.0020)\nfor t in (0.40, 0.70):\n    cable_clip('Clip2', s2, t, 0.050)\ncable('Cable_Servo', [W - v * 0.017 + w2 * 0.006,\n                      W + u3 * 0.030 - v * 0.020 + w3 * 0.006,\n                      W + u3 * 0.058 + w3 * 0.020 - v * 0.009], 0.0016)\n\n# ============================================================\n# TARGET OBJECT + SMALL DESK PARTS\n# ============================================================\nOX = Vector((obj_x, 0, 0))\ncyl('Obj_Puck', 0.020, 0.006, OX + Vector((0, 0, 0.003)), mat=alu, bevel=0.0015)\ntorus('Obj_Ring', 0.0175, 0.0012, OX + Vector((0, 0, 0.006)), mat=accent)\ncyl('Obj_Neck', 0.0115, 0.014, OX + Vector((0, 0, 0.013)), mat=alu, bevel=0.002)\ncyl('Obj_Head', 0.013, 0.016, OX + Vector((0, 0, 0.028)), mat=alu, bevel=0.004)\ntorus('Obj_Ring2', 0.0128, 0.0014, OX + Vector((0, 0, 0.024)), mat=accent)\ncyl('Obj_Socket', 0.004, 0.0015, OX + Vector((0, 0, 0.0362)), mat=alu_dark, verts=6, smooth=False)\n# small bearing + washer nearby\nBX = Vector((0.395, 0.115, 0))\ntorus('BearingOuter', 0.0095, 0.0026, BX + Vector((0, 0, 0.0032)), mat=steel)\ntorus('BearingInner', 0.0050, 0.0022, BX + Vector((0, 0, 0.0030)), mat=alu_dark)\nfor k in range(6):\n    a = 2 * pi * k / 6\n    cyl('Ball', 0.0021, 0.0042, BX + Vector((0.0074 * cos(a), 0.0074 * sin(a), 0.0031)),\n        mat=steel, verts=16)\ntorus('Washer', 0.0045, 0.0016, (0.435, 0.075, 0.0016), mat=steel)\n\n# ============================================================\n# CONTROLLER BOX + DESK CABLE\n# ============================================================\nbox('Controller', (0.10, 0.070, 0.032), (-0.20, -0.13, 0.016), mat=boxm, bevel=0.006)\nbox('ControllerLid', (0.090, 0.060, 0.003), (-0.20, -0.13, 0.0330), mat=alu_dark, bevel=0.001)\nled('CtrlLED', (-0.175, -0.145, 0.0350), (0, 0, 1), ledg, r=0.0018)\ncyl('CtrlGrommet', 0.0045, 0.005, (-0.149, -0.115, 0.014), axis=(1, 0, 0), mat=alu_dark, verts=20)\ncyl('BaseGrommet', 0.005, 0.006, (0, -0.0605, 0.022), axis=(0, 1, 0), mat=alu_dark, verts=20)\ncable('Cable_Desk', [(-0.146, -0.115, 0.014), (-0.10, -0.105, 0.005), (-0.05, -0.085, 0.004),\n                     (-0.015, -0.070, 0.005), (0.0, -0.062, 0.018)], 0.0022)\n\n# ============================================================\n# DESK, LEGS, STUDIO COVE\n# ============================================================\nbox('Desk', (1.6, 0.95, 0.045), (0.18, 0.02, -0.0225), mat=deskm, bevel=0.012)\nfor lx in (-0.48, 0.84):\n    box('DeskLeg', (0.05, 0.85, 0.755), (lx, 0.02, -0.4225), mat=alu_dark, bevel=0.008)\nprof = [(-3.0, -0.80), (1.0, -0.80)]\nfor k in range(1, 10):\n    a = pi / 2 * k / 9\n    prof.append((1.0 + 0.9 * sin(a), -0.80 + 0.9 * (1 - cos(a))))\nprof.append((1.9, 3.0))\ncverts = [(x, y, z) for (y, z) in prof for x in (-3.5, 3.5)]\ncfaces = [(2 * i, 2 * i + 1, 2 * i + 3, 2 * i + 2) for i in range(len(prof) - 1)]\ncme = bpy.data.meshes.new('Cove')\ncme.from_pydata(cverts, [], cfaces)\ncove = bpy.data.objects.new('StudioCove', cme)\nbpy.context.scene.collection.objects.link(cove)\nfor p in cme.polygons: p.use_smooth = True\ncme.materials.append(floorm)\nsol = cove.modifiers.new('Solid', 'SOLIDIFY'); sol.thickness = 0.05; sol.offset = 0.0\n\n# ============================================================\n# LIGHTING / CAMERA / WORLD\n# ============================================================\ndef area_light(name, loc, energy, size, target, color=(1, 1, 1)):\n    ld = bpy.data.lights.new(name, 'AREA'); ld.energy = energy; ld.color = color\n    ld.shape = 'DISK'; ld.size = size\n    ob = bpy.data.objects.new(name, ld)\n    bpy.context.scene.collection.objects.link(ob)\n    ob.location = loc\n    look_at(ob, target)\n    return ob\n\narea_light('Key', (0.5, -1.0, 1.6), 800, 0.9, (0.25, 0, 0.2), (1.0, 0.96, 0.90))\narea_light('Fill', (-1.1, -0.6, 0.7), 280, 0.8, (0.2, 0, 0.2), (0.85, 0.90, 1.0))\narea_light('Rim', (0.7, 1.1, 1.4), 650, 0.6, (0.3, 0, 0.25), (1.0, 0.95, 0.90))\narea_light('Top', (0.1, 0.3, 2.3), 450, 1.0, (0.2, 0, 0), (1.0, 1.0, 1.0))\n\nworld = bpy.data.worlds.new('Studio')\nscene.world = world; world.use_nodes = True\nbg = world.node_tree.nodes['Background']\nbg.inputs['Color'].default_value = (0.62, 0.63, 0.67, 1)\nbg.inputs['Strength'].default_value = 0.35\n\ncd = bpy.data.cameras.new('PresentationCam')\ncd.lens = 60; cd.sensor_width = 36\ncam = bpy.data.objects.new('PresentationCam', cd)\nbpy.context.scene.collection.objects.link(cam)\ncam.location = (1.00, -1.30, 0.58)\nlook_at(cam, (0.21, 0.0, 0.175))\ncd.dof.use_dof = True\ncd.dof.aperture_fstop = 7.0\nfocus = bpy.data.objects.new('FocusPoint', None)\nbpy.context.scene.collection.objects.link(focus)\nfocus.location = (0.37, 0, 0.15)\ncd.dof.focus_object = focus\nscene.camera = cam\n\nbpy.ops.object.select_all(action='DESELECT')\nbpy.context.view_layer.update()\n\n# ============================================================\n# SAVE\n# ============================================================\ntry:\n    bpy.ops.wm.save_as_mainfile(filepath=bpy.path.abspath('//robotic_arm_studio.blend'))\nexcept Exception as e:\n    print('Save skipped:', e)\nprint('ROBOT ARM SCENE BUILD COMPLETE')\n```","refusal":null,"reasoning":"Let me carefully plan this Blender scene.\n\nThe task: A desk-mounted robotic arm with at least 4 articulated joints, mid-reach toward a small machined object on a desk. Key design features:\n\n1. **Topology-optimized struts** on the elongated structural links between joints — organic metal members with branching transitions, lattice openings, voids. NOT on joints/base/wrist/gripper.\n2. **Precision mechanical joints**: cylindrical housings, bearings, bolted flanges, hinge pins, gearboxes, brackets, covers, interface plates. Clean base with rotating platform.\n3. **Clean cabling**: slim black lines, controlled routing.\n4. **Translucent technical membrane** spanning some openings in optimized struts (translucent TPU-like).\n5. **Two-finger parallel gripper** — machined solid, replaceable pads, pivots.\n6. **Believable mechanics**: visible rotational axes, tapering from heavy base to smaller wrist.\n7. **Setting**: clean studio/robotics lab, desk, small machined object, premium lighting.\n\nLet me think about how to build topology-optimized looking struts procedurally in Blender Python without booleans becoming a mess. \n\nApproach for organic optimized struts: Build them as a \"bone-like\" structure — a central spar with branching web members connecting two or three rails, with smooth joints. A good way: create a tapered, slightly curved main beam using metaball-like skinning? Actually a robust method: create multiple tapered tubes (curves with bevel) that split and merge — like a \"Y\" branching pattern along the length. To make it look topology optimized, the strut can be made of 2-3 longitudinal rails connected by diagonal webbing with varying thickness, plus smooth fillets.\n\nAlternative: Use the Skin modifier on a mesh skeleton with varying radii, then Subdivision Surface. That gives organic branching forms nicely. The Skin modifier approach: build an edge graph (vertices connected by edges), assign per-vertex radii, add Skin modifier → generates manifold mesh, then Subsurf level 2, smooth shading. That creates genuinely organic-looking branching topology-optimized structures. This is robust headless.\n\nPlan for a strut between joint A and joint B (in local coordinates, say along X axis from (0,0,0) to (L,0,0)):\n- Skeleton: two main rails top and bottom (offset ±r(z) in Z), maybe with X-bracing or a zigzag web between them, plus a center spine? For \"topology optimized\" look, typical designs have a tapering I-beam-like shape with organic holes. A two-rail ladder with diagonal struts and smooth branching gives that look.\n- Nodes along length: at parameter t = 0, 0.2, 0.4, ... rails at z = ±h(t) where h varies (wider near ends where loads transfer, thinner mid, or vice versa). Actually topology-optimized beams often have material concentrated near joints with voids in the middle. Let's do rails that are thicker near the ends, with the gap between rails larger near ends (deeper section) and smaller mid-span, with a few diagonal cross-links forming a triangulated web.\n- Add occasional small openings within rails? The Skin approach creates openings between rails already (the voids). \"Controlled lattice openings, carefully shaped voids\" — the ladder/triangulation gives elongated voids between members. Good.\n\nTo add a bit more \"grown\" feel, make rails slightly bowed (catenary-like curve) and add a short diagonal member that branches off and merges (like an X in the middle). Radii per node vary smoothly.\n\nThen membrane panels: for selected struts, span some of the openings with thin translucent panels — e.g., create a flat-ish mesh matching the opening outline between two adjacent segments (quad openings), solidify thin, translucent TPU material (transmission 0.7, roughness 0.3, slight tint). Attach slightly inset. Only on some openings.\n\nJoints: build from cylinders — housing (large cylinder along axis of rotation), bearing ring (torus or short cylinder), flange with bolts (cylinder + small bolt cylinders arranged in circle), gearbox (box or short wide cylinder), caps. Rotary actuator: cylinder + smaller cylinder shaft + end cap with cable port.\n\nStructure of the arm (4+ joints):\n- J1: base rotation (vertical axis) — base bolted to desk: base plate (rounded box), bolted flange with 6 bolts, rotating turret platform, rotary actuator housing (vertical cylinder).\n- J2: shoulder pitch (horizontal axis) — on top of turret, two side brackets/cheeks with bearing housings, hinge pin visible; first link (lower arm strut) goes up.\n- J3: elbow pitch — similar bearing housing; second link (upper arm, topology-optimized).\n- J4: wrist pitch — smaller; short forearm link.\n- J5: wrist roll — small rotary actuator; then gripper mount.\n- Gripper: two-finger parallel — a small gearbox body, two sliding finger rails, L-shaped machined fingers with pads; maybe small linkage.\n\nPose mid-reach: base at origin on desk (desk at z=0? let's set desk top at z=0, base sits on it). Arm reaches forward toward a small object (e.g., a small machined metal cube/cylinder part, like a knurled knob or a bearing block) on the desk ~0.55 m away.\n\nDimensions: desk at z=0. Base ~0.14 m tall, arm reach total ~0.6-0.7 m. Scale everything in meters.\n\nLet me define joint positions via a simple FK chain:\n- Base center at (0, 0, 0). Base plate on desk.\n- J1 axis vertical at z ~ 0.10. Turret rotates so arm faces +X direction (toward object at +X).\n- J2 (shoulder) at (0, 0, 0.20) approx, axis along Y.\n- Link 1 (upper arm) length L1 = 0.34, angle from vertical: leaning forward ~35°.\n- J3 (elbow) at end of link1.\n- Link 2 (forearm) length L2 = 0.30, angled down-forward so wrist approaches object height ~0.06 above desk.\n- J4 wrist pitch at end of link2; wrist roll then gripper pointing down-forward toward object.\n\nCompute: shoulder at (0,0,0.22). Link1 at angle θ1 from vertical toward +X: 40°. Elbow at (sin40*0.34, 0, 0.22+cos40*0.34) = (0.2186, 0, 0.4804). Hmm that's fairly high. Link2 angle from vertical: 75° forward (i.e., mostly horizontal pointing down?). Let's param angle from vertical downward... Let me param: link2 direction making angle φ from horizontal. Want wrist at roughly (0.52, 0, 0.10). From elbow (0.219, 0, 0.480): delta = (0.301, -0.380), length = sqrt(0.0906+0.1444)=sqrt(0.235)=0.485 — too long for 0.30. Adjust: bring object closer: object at (0.45, 0, 0.02). Wrist target (0.42, 0, 0.09). Delta from elbow: (0.201, -0.390), len = sqrt(0.0404+0.1521)=0.439. Still >0.30. So either longer L2 or lower shoulder/elbow.\n\nLet me choose: shoulder height 0.19, L1 = 0.30 at 50° from vertical: elbow at (0.30*sin50, 0, 0.19+0.30*cos50) = (0.2298, 0, 0.3828). L2 = 0.32. Wrist target (0.44, 0, 0.10): delta (0.2102, -0.2828), len = 0.3523. Slightly over. Wrist (0.42,0,0.12): delta (0.1902,-0.2628) len 0.3244 ≈ L2 0.32. OK close enough — tune precisely in code by computing the direction and placing wrist at elbow + dir * L2, then place the object near gripper tip accordingly. Better: compute gripper tip from FK, then place the small object just in front of/below the gripper tip on the desk. That guarantees \"reaching toward a small object\" alignment. I'll compute positions in Python with math.\n\nGripper: from wrist, a short tool flange + gripper body length ~0.07, fingers extend ~0.05. The fingers point along link2 direction continued (with wrist pitch adjusting to aim slightly downward at object). Simplify: wrist pitch axis Y, then tool direction = link2 direction rotated by a small angle so the gripper points down toward the object at ~ 30° below horizontal.\n\nSimplification for robustness: I'll compute angles numerically:\n- dir1 = angle a1 from vertical (forward +X). \n- Elbow E = S + L1*(sin a1, 0, cos a1).\n- Choose wrist W explicitly = (0.42, 0, 0.115). Then a2 direction = normalize(W-E). Gripper axis direction d3 = rotate toward object: aim at object O on desk: d3 = normalize(O - (W + small offset)). Gripper length ~0.11 from W to fingertips. Set object O such that fingers hover just above/around it: fingertips at W + d3*0.12, object at fingertips + d3*0.02 minus desk offset... Actually to avoid intersection with desk, place object on desk (z = object height/2 ~ 0.02), and fingertips slightly above desk: fingertip z ~0.035, object height 0.03. Let me just place fingertips at z≈0.045 and object directly below fingertips plus a bit forward. Fine.\n\nNow details for each component.\n\nMaterials:\n- Optimized struts: bead-blasted titanium / aluminum — metallic 0.95, roughness 0.32, light gray with slight warm tint. Maybe subtle anisotropy.\n- Joint housings: machined aluminum — metallic 1.0, roughness 0.22, light silver; some darker anodized parts (dark gray, metallic 0.9 roughness 0.3); accent anodized orange or blue small rings for design flair (research prototype look — e.g., orange accent rings).\n- Bearings: dark steel.\n- Bolts: steel with slight roughness 0.25.\n- Membrane: translucent TPU — Principled: Transmission weight 0.85, roughness 0.35, IOR 1.4, base color slightly smoky (0.9,0.93,0.95), alpha? In Cycles use transmission; thickness via Solidify. For GLB export, transmission maps to alpha blend-ish; okay best effort. Maybe give slight tint amber? Keep neutral smoky.\n- Cables: black rubber — roughness 0.6, near black.\n- Gripper pads: dark rubbery or brass contact pads — use amber/orange urethane pads.\n- Desk: matte light warm gray or pale wood? \"clean contemporary design studio\" — desk in matte light gray/white laminate with subtle bevel. Maybe a soft oak? Keep light neutral gray.\n- Background: large soft cyclorama — a curved backdrop plane (sweep from floor to wall) in light warm gray, or just world + big area lights. A studio backdrop: floor plane + wall with curved transition. Build with a mesh and bevel, or simply large floor plane and rely on world light gray. I'll build a curved backdrop (cove) mesh — looks premium.\n- Small object on desk: a precision machined part — e.g., a small stepped cylinder \"knob\" with knurled band (knurl via torus with small teeth? or just grooves via torus stack), aluminum with orange anodized ring. Make it look like a machined demo part: stepped puck with a hex top? A small hex-socket cap shape. Keep simple: stepped cylinders + torus groove + a small hex head on top (cylinder 6 verts). \n\nLighting: \n- Key: large area light upper-left front, warm-neutral 5500K, soft.\n- Fill: area light right, cooler, dimmer.\n- Rim: area behind/top for edge highlight.\n- Plus a soft overhead area. World: light gray 0.05-0.08 strength or use gradient via world color. Keep world slightly gray (0.3 strength gray) for ambient.\n- Maybe a subtle spotlight on object? Not necessary.\n\nCamera: square 1536. Position to show arm side-front 3/4 view: object to the right of frame, base left. Arm extends along +X; camera at about (1.15, -1.05, 0.62) looking at (0.28, 0, 0.26)? Let me think: keep both base and object in frame with some margin. Arm spans x from -0.1 to 0.55. Frame center ~ (0.22, 0, 0.22). Camera at (0.95, -1.15, 0.55) with 70mm lens? For product look, use 70-85mm equivalent, camera farther: (1.6, -1.9, 0.95) aiming at (0.2, 0.05, 0.24). I'll compute track-to with constraint or manual rotation via look-at function. Write a helper `look_at(obj, target)`.\n\nAlso add desk as a rounded slab: big rounded cube (bevelled) top at z=0, e.g., 2.2 x 1.4 x 0.06, top z=0 so body extends down. Position desk so arm near one end, maybe include subtle desk edge in frame. Also a second small prop? Maybe a small parts tray or a second object — keep minimal: the target object plus maybe a tiny washer nearby. Also a control box? Keep it clean: just the arm + object + desk. Maybe add a slim cable from base to a small control module box at the desk rear — shows \"controlled cable routing\". A compact black controller box with a slim cable to base. Good detail, keep it tidy with a curve cable that hugs the desk.\n\nAlso recessed cable guides along arm: run one slim black cable along the struts using small clip rings — curve with bevel, clipped at 2-3 points per link with small torus/clip mounts. Keep it close to the structure, inner side.\n\nJoint construction details:\n\nBase assembly:\n1. Desk-mounted base plate: rounded square plate 0.16 x 0.16 x 0.012 at z=0.006, dark anodized, with 4 counterbored bolts at corners (small cylinders + hex heads).\n2. Lower base housing: cylinder r=0.055, h=0.03 on plate; chamfer (bevel modifier applied or use bevelled cylinder by adding bevel modifier and applying? For headless robustness, apply bevel modifier via modifier stack then apply). Actually simpler: use bevelled cylinders via bevel modifier with segments 2-3, apply. I'll write helper `bevel(obj, width, segments)` applying modifier.\n3. Bearing ring: torus or short cylinder r=0.05 at z=0.045, darker steel.\n4. Rotating turret: cylinder r=0.048 h=0.035 + top interface plate; accent ring (orange anodized) thin torus between base and turret — subtle.\n5. On turret: shoulder joint housing — two cheek plates (rounded boxes) flanking the arm root, with cylindrical bearing caps on outer faces (axis along Y). Hinge pin visible: cylinder along Y through both cheeks, with end caps + bolts.\n6. Cable port at back of turret with a slim cable loop down to base port (internal channel look) — small curve.\n\nShoulder joint (J2): housing cylinders along Y: main housing r=0.032 length 0.075 (through both cheeks), bearing caps r=0.026, end caps with 4 small bolts each, center gearbox cylinder r=0.036? Hmm widths: cheeks at y=±0.045. Housing spans y=-0.06..0.06.\n\nLower arm strut (Link 1): topology-optimized member from shoulder (J2) to elbow (J3). Attach via interface plates at each end: small machined hub cylinders at both ends that the organic strut visually grows out of. Strut skeleton in local frame, then orient. Build the strut geometry in world space directly by computing positions along the segment from J2 to J3 (minus hub lengths). Helper function `make_optimized_strut(p_start, p_end, width_start, width_end, thickness...)`.\n\nStrut skeleton design (per strut): local axis u (from A to B), with side vectors v (lateral) and w (vertical-ish). Rails: two rails offset in ±w (in the plane of bending — the arm's bending plane is XZ, so w = in-plane perpendicular; rails top and bottom of the beam section). Optionally a third element: diagonal webbing zigzag between rails. Node count n=9 along length. Rail offset h(t) = base + bulge: h(t) = mix(hA, hB, t) * (1 + 0.35*sin(pi*t))? Actually topology-optimized look: deeper near middle or ends? Real TO brackets often deeper where moment is high (near fixed end) — make depth larger near ends, pinched mid? Let's do: depth d(t) = lerp(dA, dB, t) * (0.75 + 0.5 * (cos(2π t)*0.5+0.5))? That gives max at ends, min mid — creates an hourglass beam with big openings mid — looks organic. With diagonal webbing crossing the void.\n\nRadii: rail radius r(t) = lerp(rA, rB, t) * (1 - 0.25*sin(pi t))? Thinner at mid? Or keep thicker at nodes (joints) and thinner between — organic bone look: nodes slightly swollen (like bone knuckles). Per-vertex radius: base(t) * (1 + 0.3 * bump at attachment zones).\n\nEdges: rails as chains; diagonals connecting top node i to bottom node i+1 alternating (zigzag), plus maybe an X at the middle bay. Add short horizontal cross-members between rails at t=0 and t=1 (the attach hubs merge into rails).\n\nSkin modifier: add, then set each vertex's skin radius (via `obj.data.skin_vertices[0].data[i].radius = (rx, ry)`). Then add Subsurf (level 2) and smooth shading. Also mark root? Skin modifier needs a root vertex usually for correct generation in some contexts but for pure mesh generation it works without armature; set `mark_root` maybe not needed. Known: Skin modifier works on edges; need at least one vertex marked root when used with armature but for geometry it's fine. I'll mark vertex 0 as root to be safe.\n\nThen add membrane panels on selected bays: quads connecting top node i..i+1 and bottom node i..i+1 where there's no diagonal crossing (or over the diagonal? a panel over an opening with diagonal inside shows \"lightly revealing structure beneath\" — nice: translucent panel over a bay that has a diagonal strut). Panel: create quad slightly inset (scale 0.9 toward bay center), solidify 0.0015m, subsurf 2 with supporting loops? Simpler: quad with slight outward bow — make it a grid 4x4 with slight offset along normal, subsurf 2. Or just flat quad with Solidify + Bevel — flat taut film is fine (\"tensioned mesh/film\"). I'll make slightly bowed panel (bulge 3mm) via subdivided grid + subsurf, gives taut tensioned look. Solidify after subsurf. Keep membrane only on 2-3 bays of link1 and maybe 1-2 of link2; leave others open.\n\nElbow joint (J3): similar to shoulder but smaller: hinge axis Y, housing r=0.026, cheeks on link1 end or on link2? Make elbow: link1 end has fork cheeks; link2 root has central hub that rotates between them; hinge pin through; bearing caps outside; small gearbox/motor cylinder attached on side (r=0.02, axis Y, extends y+) with cable.\n\nForearm strut (Link 2): smaller TO strut from elbow to wrist pitch, with its own hubs.\n\nWrist (J4): pitch joint small housing r=0.018 axis Y; then wrist roll (J5): small rotary actuator cylinder along tool direction r=0.016 length 0.03 with accent ring; then tool flange (disc with 4 bolts) then gripper.\n\nGripper: \n- Gripper body: small rounded box (0.05 x 0.035 x 0.03) with a front slot.\n- Two finger carriages: small boxes on rails, spaced ±0.012 in Y (parallel gripper opens laterally). Rails: two slim cylinders along Y spanning body front? Parallel gripper: fingers move toward/away along Y. Fingers: L-shaped machined plates: from carriage extend forward (along tool dir) 0.045 as flat plates 0.006 thick in Y, then pads on inner faces at tips: small blocks 0.008 with orange urethane pads.\n- Visible pivots/actuation: small servo cylinder on top of body + tiny linkage rods? Keep believable: a compact linear actuator (small cylinder) on the back driving a wedge — visually: small motor cylinder on body top + a pair of tiny pin joints on fingers. Also add small bolts.\n- Fingers solid machined — boxes with bevel, no lattice.\n\nCable routing: \n- One main cable: from base rear port up the inside of link1 (clips at 2 points) to elbow motor, another from elbow along link2 to wrist. Use curves bevel_depth 0.0022, black. Keep tight to structure: compute path points offset from strut centerline toward -w (inside). Clips: small torus around? Simpler: small dark clamps (tiny boxes) at clip points. Good enough.\n\nRotational axes visibility: hinge pins with contrasting end caps (orange ring + steel cap) on both sides; bolts circles on caps.\n\nNow the desk & studio:\n- Desk slab: 2.4 x 1.3 x 0.05 rounded (bevel 0.02), top z=0, centered maybe at (0.3, 0.1, -0.025) so base near back-left region and camera sees front edge. Actually base at origin; desk center at (0.25, -0.05, -0.026), size 1.9 x 1.1. Keep desk edges within/around frame.\n- Backdrop: a large curved cove behind: floor plane big + wall; or seamless cyclorama mesh: I'll build a profile curve extruded: floor from y=-? Hmm orientation: camera looks from -Y toward +Y? Camera at y=-1.9 looking at origin → background at +Y. Cove: floor extends from y=-3 to y=+2.5 at z=-0.05 (under desk? desk sits on floor? Desk is the table; floor below at z=-0.85 with desk legs? Simpler: present the desk as a floating studio surface? Task says \"desk-mounted ... on a desk\". Give desk visible legs? A clean studio table: slab + 2 panel legs or a single panel leg. To keep composition at 1536² with arm ~0.5m tall, showing legs means wide framing. Alternatively frame crop: desk fills lower frame, backdrop cove directly behind/under desk (like desk in front of studio sweep, floor not visible). I'll put the cove right behind the desk and let the desk slab extend to the frame bottom — camera slightly above looking down a bit, desk surface visible, wall cove behind. Desk thickness visible at front edge. No legs needed if cropped — but 360° orbit view! The benchmark also renders a 360 orbit. So the scene should look complete from all sides: give the desk legs (panel legs or cylindrical) and a floor. Let's do: floor at z=-0.78 (desk height ~75cm), desk slab with 4 slim round legs or 2 panel legs. Panel legs (rounded boxes) look studio-modern. Floor: big plane with subtle roughness, light gray. Backdrop wall at y=+2.2 tall. Or cove curve. I'll build floor plane 20x20 and a curved cove wall behind (y>1.2) — but orbit from other sides would see wall edge. Use a full room? For a 360 orbit, typical studio: infinite white-ish floor with soft radial gradient and world gray — acceptable. I'll do: big floor plane (light warm gray, roughness 0.5), plus a large background cylinder? A giant cylinder around (r=6) interior lit gives seamless look from all directions. Could look odd. Simplest robust: floor plane + world light gray; horizon naturally fades. With filmic/agX, looks clean studio. Also add subtle dark vignette via compositor? Not needed.\n\nAdd desk legs: two panel legs near ends.\n\nSmall object: at computed target: a machined part — base puck r=0.018 h=0.008, shaft r=0.010 h=0.012, top hex r=0.012 h=0.008 (6-gon), anodized blue? Keep aluminum + one orange ring. Also a tiny washer beside? Place a second small part: a small bearing (torus + ring) lying near — nice for \"picking up small desk objects\" context. Keep 1 main target + 1 small extra.\n\nAlso add a compact controller box on desk behind base with cable: box 0.09x0.06x0.03 dark, small LED (emissive dot), slim cable to base. Cable: curve lying on desk, neat straight-ish with gentle bend. Adds lab believability. Status LEDs on joints: tiny emissive dots (green/amber) — nice research-prototype touch, small.\n\nNow materials via helper `mat_principled(name, color, metallic, roughness, ...)`.\n\nBevel helper: apply bevel modifier. In Blender 5.1, `bpy.ops.object.modifier_apply` requires context override or use `bpy.context.view_layer.objects.active`. Headless fine with `bpy.context`.\n\nShading smooth: for cylinders set `data.polygons foreach set use_smooth`? Use `for p in obj.data.polygons: p.use_smooth = True` then add weighted normals via bevel modifier's `harden_normals`? WeightedNormal modifier exists. Simpler: bevel mod + set smooth + `obj.data.set_sharp_from_angle`? Auto smooth changed in 4.1+. Use smooth shading + bevel; add \"Weighted Normal\" modifier maybe removed? WeightedNormal still exists in 5.x I believe. To be safe: smooth shading + bevel segments=3 looks fine.\n\nCreate cylinder helper: `add_cyl(radius, depth, loc, rot, verts=48)`.\n\nBolts helper: hex head bolt = cylinder(verts=6) small + washer? Just hex head + short shaft. Arrange in circle helper `bolt_circle(center, axis, radius, n, bolt_r, ...)`.\n\nOrientation helpers: rotate cylinder (default axis Z) to axis: use quaternion `Vector((0,0,1)).rotation_difference(dir)`.\n\nSkin strut builder — most complex part. Steps:\n1. Compute frame: u = normalize(B-A); pick w = component of global Z perpendicular to u? The bending plane for links is XZ plane, so side vector v = global Y (0,1,0) mostly; w = u × v normalized. Compute v = normalize(cross(w0? )). Let's set: v = (0,1,0) (lateral, hinge axis direction), w = normalize(cross(u, v)) — in-plane perpendicular. Rails offset ±w * d(t)/2; slight v variation? Keep planar — fine, plus maybe slight lateral flare at ends? Keep planar for cleanliness; add slight bow: rails get extra offset along w by bow(t)=0.02*sin(pi t)*sign to look organically curved (top rail bows up, bottom bows down — already the ±w with varying d gives shape). Additionally make the centerline itself slightly curved: offset c(t) = bend * sin(pi t) along w for whole strut — a gentle arc looks grown. Small amount 0.015.\n\n2. Nodes: n = 10 segments. For i in 0..n: t=i/n; center C = A + u*(L*t) + w*bend*sin(pi*t); half-depth h(t) = (dA + (dB-dA)*t)/2 * prof(t), prof(t) = 0.62 + 0.55*(0.5+0.5*cos(2π t))? That ranges 0.62..1.17 at ends... hmm want depth bigger at ends: prof = 0.6 + 0.55*abs(cos(π t))^0.8? At t=0.5, cos(π/2)=0 → prof=0.6 min mid; ends 1.15. Good: prof(t) = 0.6 + 0.55*abs(cos(pi*t))**0.75.\nTop node T_i = C + w*h(t); bottom D_i = C - w*h(t). Maybe also mid node for triangulation? Diagonals: edges T_i→D_{i+1} for even i, D_i→T_{i+1} for odd i (zigzag). Additionally, add short cross edge T_0—D_0 and T_n—D_n.\n3. Radii: rail node radius rr(t) = (rA + (rB-rA)*t) * (1.25 - 0.5*sin(pi*t))? At mid 0.75x, ends 1.25x. Diagonal nodes share same per-node radius (nodes are shared). Node radii: top nodes get rail radius; diagonal edges use node radii. With shared nodes it's consistent.\nNode radius values: link1: rA≈0.011 at shoulder end, rB≈0.008 at elbow. Depth dA=0.075, dB=0.05.\n4. Extra \"grown\" detail: add a mid-spine? Maybe skip; zigzag gives triangulated organic look. Add one extra diagonal in middle bay making an X.\n5. Mesh: verts list, edges list. Create mesh, skin modifier, set radii per vertex: need `me.skin_vertices` after adding modifier? Skin data: when creating mesh from_pydata, then add Skin modifier — the skin vertex data layer created automatically? In Blender, `mesh.skin_vertices` exists once a Skin modifier is added? Actually the skin vertices data layer is created when modifier added via `obj.modifiers.new(type='SKIN')`. Yes, then `me.skin_vertices[0].data` has one entry per vertex. Set radius. Then Subsurf modifier levels 2. Optionally apply skin then subsurf for membrane fitting? Keep modifiers unapplied (GLB exporter applies modifiers at export — glTF exporter does apply modifiers. Yes, exporter applies modifiers by default. Cycles render also evaluates. Fine.)\n\nPotential pitfall: Skin modifier may produce twisted frames at branch nodes; with smooth radius it's usually fine.\n\nAlso mark loose root: set `sv.use_root = True`? attribute `use_root`? For skin_vertices data each has `use_root`? It's `SkinVertex.use_root`? In bpy, `mesh.skin_vertices[0].data[i].use_root`. Hmm, attribute might be `use_root`. I think it's fine without.\n\nLet me double check: `bpy.types.SkinVertex` has properties: `radius` (float[2]), `use_loose`, `use_root`. Yes.\n\n6. Interface hubs: at each strut end, a machined hub: short cylinder along u (r slightly larger than local depth/2 +0.005? no—hub r ≈ rail attach zone) with flange + bolts connecting to joint clevis. Hub: cylinder r_hub along u length 0.03, plus collar torus, plus 4 bolts on flange face. The strut tips (first/last nodes at t=0,1 with radius rA*1.25) visually merge into hub — position hubs so strut end nodes embed inside hub cylinder.\n\nMembrane panels: choose bays (between node i and i+1) list per strut. Panel quad corners: interpolate rail nodes inset: P = lerp corners toward bay centroid by 0.12 to create margin (film inset within frame, slightly revealing edges). Add slight bulge along ±v? Membrane spans in the plane of the bay (the bay lies in u-w plane; film covers it like a drum). Tensioned film would be flat; slight outward bow ±0.002 along v. Build grid 5x5 with bow = 0.0025*sin(pi*s)*sin(pi*r) along normal v. Subsurf 1? grid dense enough; add Solidify thickness 0.0012. Material TPU translucent. Also maybe perforation? skip.\n\nFor GLB: transmission becomes... glTF exporter exports Transmission as KHR_materials_transmission — good, supported by viewers roughly. OK.\n\nCables as Bezier/NURBS poly curves with bevel. Use bevel_depth and polyline through points with Catmull? Use NURBS or simple bevelled poly spline with many sampled points (smooth via interpolation). I'll create Curve with spline type 'BEZIER' and set handles AUTO for smoothness.\n\nJoint limits detail: add small mechanical stop blocks on joints (tiny tabs) — nice touch, 1-2 small boxes.\n\nEncoder covers: small round caps on one side of each joint (cylinder r smaller, dark) — believable.\n\nNow assembly pieces per joint (concrete):\n\nBASE (J0/J1):\n- base_plate: rounded box 0.17×0.17×0.014 at z 0.007; dark gray anodized; 4 corner bolts (hex r 0.004).\n- base_lower: cylinder r=0.062 depth 0.03 z=0.014+0.015 → center 0.029? plate top at 0.014; cyl from 0.014 to 0.046.\n- bearing ring: r=0.056 depth 0.012 z 0.046..0.058 dark steel + orange thin ring accent at seam (r 0.0565 depth 0.002).\n- turret: r=0.05 depth 0.035 z 0.058..0.093.\n- turret top plate: r=0.055 depth 0.008 z 0.093..0.101 with 6 bolts on its top face circle r=0.044.\n- shoulder cheeks: two rounded boxes 0.05(x)×0.012(y)×0.075(z) centered x=0? The shoulder axis at z_sh = 0.165. Cheeks from z 0.10 to 0.18 at y=±0.043. Actually cheek plates bolt onto turret top. Cheek box dims: x 0.055, y 0.014, z 0.08, center (0, ±0.043, 0.14). Bearing caps: cylinders axis Y at y=±(0.043+0.007..+0.02): outer cap r=0.03 depth 0.012 centered y=±0.056, z=0.165. Hinge pin: cylinder r=0.011 axis Y spanning y -0.062..0.062 at z=0.165. End nuts: hex at y=±0.065.\n- motor for J2: cylinder r=0.024 depth 0.05 axis Y mounted behind? Place on -Y side: housing r=0.026 from y=-0.056 to -0.106 (depth 0.05) centered y=-0.081 z=0.165, with end cap + cable stub from cap going down into turret (curve). \n\nLink1 root hub attached between cheeks: hub cylinder axis along link1 dir at start point A1 = (0,0,0.165) extending toward elbow: hub from t=-0.02 to 0.035 along u1. Hub r=0.026. Cross pin through hub & cheeks is the J2 pin (same axis z=0.165). Good: hub center at A1.\n\nCompute A1 = S = (0, 0, 0.165). a1 = 48° from vertical (toward +X). u1 = (sin48, 0, cos48) = (0.7431, 0, 0.6691). L1 = 0.30. Elbow E = S + 0.30*u1 = (0.2229, 0, 0.3657).\n\nChoose wrist W: want reach: a2 such that forearm goes down-forward. W = (0.435, 0, 0.150). vec EW = (0.2121, -0.2157), len = 0.3024 → set L2 = 0.3024 exact (compute in code). u2 = normalize.\n\nWrist joint at W: wrist pitch axis Y. Tool direction: aim at object. Gripper assembly: from W, tool mount extends along u3. Let object top point target G = W + u3 * 0.11 where u3 = rotate u2 further downward by angle β = 25° (more vertical). u2 angle from horizontal: atan2(-0.2157, 0.2121) → -45.5°. u3 = -70.5° from horizontal (pointing down steeply). Fingertips at W + u3*0.115: = (0.435+0.0384, 0, 0.150-0.1084) = (0.4734, 0, 0.0416). Object on desk top z: object height ~0.028 → top z=0.028, center (0.4734+ small x?, 0). Fingertips at z 0.042 hovering just above object top (0.028): gap 0.014 — fingers on either side (Y ±0.014) poised to grab. Looks mid-reach, about to grasp. Object center x = fingertips x + 0.005 = 0.478. Good.\n\nELBOW (J3): axis Y at E. Link1 end hub at E (cylinder along u1 r=0.022 depth 0.05 centered at E - u1*0.01). Cheeks of link2 root: two plates y=±0.032 around E, extending along u2 0.05. Bearing caps axis Y r=0.022 at y=±0.038, pin r=0.008. Motor on +Y side: r=0.02 depth 0.045 centered y=0.06. Encoder cap on -Y: r=0.016 depth 0.008 dark.\n\nHub2 (link2 root between cheeks): cylinder axis u2 r=0.02 from E-0.01 to E+0.03.\n\nLink2 strut from E + u2*0.025 to W - u2*0.03 (hub lengths), depth 0.05→0.032, radii 0.0075→0.0055.\n\nWRIST (J4) at W: small housing axis Y: cheeks from link2 end? Make wrist: link2 end hub r=0.016 axis u2; wrist block: cylinder axis Y r=0.018 depth 0.05 (y -0.025..0.025) at W — the rotating part attaches tool. Bearing caps r=0.014 y=±0.027. Small motor r=0.014 depth 0.03 on +Y at y=0.038. Pin r=0.006.\n\nWRIST ROLL (J5): from W along u3: actuator cylinder r=0.016 depth 0.038 centered W+u3*0.019 (axis u3) — housing attached to wrist block rotates around u3. Accent ring. Tool flange disc r=0.02 depth 0.006 at W+u3*0.042 with 4 bolts.\n\nGRIPPER at GP = W + u3*0.048: body box 0.036 (along u3) × 0.042 (y) × 0.026 (w3) — need orientation frame: u3 tool axis, v=Y lateral, w3 = cross(u3, v). Body rounded box bevel 0.004. \n- Top servo: small cylinder r=0.009 depth 0.02 along w3 on top? place on -w3 side (top relative world up?) w3 = cross(u3, v): u3 ≈ (0.334, 0, -0.943); cross(u3,(0,1,0)) = (u3.y*0 - u3.z*1, u3.z*0 - u3.x*0, u3.x*1 - u3.y*0) = (0.943, 0, 0.334). That points up-forward (+x,+z). So w3 is the \"top\" side of tool. Servo on top at GP + w3*0.018: cylinder axis w3 r=0.0085 depth 0.016. Cable from servo to wrist motor along body (short curve).\n- Finger rails: two parallel rods axis v (Y) spanning body front? For parallel gripper, fingers slide along Y. Rods: cylinders r=0.003 axis Y length 0.05 at GP + u3*0.012 ± w3*0.008, ends held by body end plates: two small plates at y=±0.021 (boxes 0.03×0.004×0.02).\n- Fingers: carriages: boxes 0.014×0.008×0.018 at y=±0.014, positioned GP + u3*0.012. Finger plates extend +u3: from carriage, plate dims: length 0.05 along u3, thickness 0.0045 in Y, height 0.014 in w3 → box centered at GP + u3*0.037 + y=±0.014. Tips: pads on inner faces (y facing center): pad box 0.012×0.004×0.012 at GP + u3*0.058, y=±0.0115, orange urethane. Also small pivot pins on carriage (visible pivots): cylinders r=0.003 axis w3? Add pin through finger root: cylinder axis w3 r=0.0028 at carriage with end caps — suggests linkage. Plus tiny linkage rod from servo wedge to finger: thin cylinder connecting servo bottom to finger mid — adds believability; two rods.\n- Gripper open gap: pads inner faces at y=±0.0095; object max radius 0.012?? Object puck r=0.018 → fingers wouldn't close around but mid-reach open pose is fine: gap 0.019 vs object head r=0.012 (hex top across ~0.024?) Keep object top shaft r=0.009 → fits gap. Pads hover beside object head? Pads at z around fingertip z 0.042; object head at z 0.02..0.028 — pads slightly above. Adjust: fingers a bit lower or object taller: make object total height 0.036 (like a small knob), head z 0.028..0.036, pads at z ~0.038..0.05 hovering just above head, fingers beside head region at y ±0.011 vs head r 0.009: gap 2mm each side. Believable \"about to grab\". Good enough; slight mismatch ok since mid-reach.\n\nNumbers computed at runtime — I'll compute G target then place object. To be safe about desk intersection: lowest fingertip z = 0.0416 - pad half height (0.006) ≈ 0.035 > 0. OK.\n\nBolts everywhere: flange bolt circles: base top plate 6 bolts; hub flanges 4 bolts each; gripper flange 4 bolts; cheek caps 4 small bolts each. Helper `bolt_ring(center, axis, ring_r, n, r_bolt, depth)`.\n\nAlso add subtle panel lines? skip.\n\nDesk props: controller box at (-0.16, 0.14, z on desk) with LED; cable from box to base rear (curve on desk surface). Also maybe a slim monitor arm? Too much. Add small nameplate on base? skip.\n\nExtra small part: a tiny bearing near object: torus r=0.008 + inner ring, lying flat at (0.40, 0.10). And maybe two M3 washers. Keep 1-2.\n\nGround/floor: big plane 30x30 at z=-0.78, light gray, rough 0.6. Desk legs: 2 panel legs 0.05 thick: boxes 0.7(y)×0.04(x)×0.72 at x = 0.0? Desk slab: center (0.15, 0, -0.036), dims 1.5×0.9×0.045 → top z=-0.0135?? Set slab top at z=0: center z = -0.0225. Legs under: at x=-0.45 and x=0.75? Desk x range 0.15±0.75 → -0.6..0.9. Legs at x=-0.5, 0.8, y=0, panel dims (0.05 x, 0.8 y, 0.755 z) center z = -0.045-0.3775 = -0.4225 → from -0.045 to -0.8. Floor at -0.80. Legs bevel 0.008. Desk bevel 0.012.\n\nHmm wait: is base at x=0 with object at 0.478 — desk extends to 0.9, fine. Controller at x=-0.2? within desk. Fine.\n\nBackdrop: since orbit renders around, a clean floor + world suffices. Add a subtle large softbox card? The area lights themselves. Maybe add a big vertical gradient backdrop plane behind (y=+1.6) light gray — from other orbit angles it'd float. Skip; keep floor + world. World color: use nodes with Background color (0.055 gray) strength? For studio look, world slightly bright: color 0.8 gray at strength 0.35 gives soft ambient + gray horizon. In render, background will be mid-gray — premium with rim lights. Maybe use a gradient world? Keep simple gray.\n\nColor management: AgX (default in 5.x) with look 'AgX - Medium High Contrast'? Set `scene.view_settings.look = 'AgX - Medium High Contrast'`? In 5.1 look options: 'AgX - Medium High Contrast' exists (Blender 4.x). 5.1: might be renamed... Safer: set display_settings? I'll try setting look in try/except.\n\nCamera: compute target (0.22, 0.02, 0.20). Camera pos: from front-right? Arm extends +X; nice view from (0.95, -1.05, 0.55) — 3/4 front-left? Y negative is front. Distance ~1.5. Lens 58mm? With square frame 1536, sensor 36mm: FOV ~ 2*atan(18/58)=34.4°. Arm bounding ~0.75 wide, 0.5 tall. Distance 1.5 at 34° covers ~0.92 wide — ok with margin. Let's place camera (1.05, -1.25, 0.62), lens 60, target (0.20, 0, 0.19). Check vertical: target z 0.19 mid of arm height 0..0.48? Base bottom 0, top elbow 0.366 + caps ~0.39; desk front edge at z -0.045 visible bottom. Should fit.\n\nI'll add a slight depth of field: f-stop 5.6 focus on elbow/gripper mid (focus object empty at (0.35,0,0.15))? DOF adds premium look; but benchmark 360 orbit uses same camera only for presentation; orbit likely overrides camera anyway. DOF at f/5.6 mild. Use focus_empty at gripper (0.44,0,0.12), fstop 6. Background slightly soft. OK.\n\nLights:\n- key: area, size 0.9, energy 900W? Scale: scene ~1m; use energy 700, loc (0.6, -0.9, 1.6), pointing at (0.25,0,0.2). Area light size 0.8 for soft.\n- fill: area size 0.7 energy 350, loc (-1.0, -0.4, 0.9), cool tint (0.85,0.9,1.0), target (0.2,0,0.2).\n- rim/top: area size 0.6 energy 600, loc (0.2, 0.9, 1.5) target elbow — creates top/back edge light.\n- small spot/area on gripper region: area 0.3 energy 150 at (0.9, -0.3, 0.7) aimed at gripper for sparkle? Optional.\nSet light color key slightly warm (1.0, 0.96, 0.9).\n\nUse light_energy units W. At scene scale meters with cycles, 400-1000 typical.\n\nAlso enable contact shadows? Cycles handles.\n\nMesh helpers:\n\n```python\ndef box(name, loc, scale_dims, mat, bevel_w=0.0):\n    bpy.ops.mesh.primitive_cube_add(location=loc)\n    o = bpy.context.active_object; o.name=name\n    o.dimensions = dims\n    bpy.ops.object.transform_apply(location=False, rotation=False, scale=True)\n    if bevel_w>0: add bevel mod apply\n    assign mat\n```\n\nOrientation for boxes: pass rotation too (e.g., finger plates aligned to u3: rotation about Y by angle). Use quaternion from basis: build matrix from (u3, v, w3) columns. Helper `orient_obj(obj, x_axis, y_axis, z_axis)` set matrix_world rotation from Matrix((x,y,z)).transposed() → 4x4 with translation.\n\nCylinders aligned: `cyl(name, r, depth, loc, axis=None, verts=48, mat, bevel)`: create with rotation quaternion if axis given.\n\nBevel modifier application: \n```python\ndef bevel(obj, w, seg=3):\n    m = obj.modifiers.new('bev','BEVEL'); m.width=w; m.segments=seg\n    bpy.context.view_layer.objects.active = obj\n    bpy.ops.object.modifier_apply(modifier=m.name)\n```\nApplying many modifiers headless is fine but slower; scene moderate (~150 objs). OK.\n\nFor smooth shading cylinders: after bevel, set polygons smooth. But end cap n-gons smooth cause shading artifacts; with bevel + smooth by angle better: use `obj.data.set_sharp_from_angle`? In 5.x, use modifier \"NODES\"? Simpler: keep flat shading for small parts; for larger visible housings, smooth + bevel gives decent look; caps may show minor artifacts — mitigate by using bevel segments 3 and setting `m.limit_method='ANGLE'` and shading smooth with autosmooth via geometry nodes? There's `bpy.ops.object.shade_smooth_by_angle()` in 4.1+ (operator). In 5.1: `bpy.ops.object.shade_smooth(use_auto_smooth?)`? The operator `shade_smooth_by_angle` exists in 4.1+? I recall `bpy.ops.object.shade_smooth_by_angle()` added in 4.1. Hmm risky. Alternative: mesh.set_sharp_from_angle is a Mesh method (`mesh.set_sharp_from_angle(angle=...)`) added 4.1? There's `bpy.ops.mesh.customdata_custom_splitnormals_clear`... \n\nSimplest robust: for cylinders, after creation with `bpy.ops.mesh.primitive_cylinder_add`, do: for polys: use_smooth = (len(p.vertices)==4)? side quads are 4-verts; caps are n-gons (len>4) → smooth only side faces; caps stay flat → clean look without auto smooth. With bevel modifier applied, bevel faces are quads too (smooth ok). Do this: `for p in me.polygons: p.use_smooth = len(p.vertices) <= 4`. Bevel creates quads & maybe n-gon remnants? After bevel on cylinder, caps become n-gon rings still n-gons. Works.\n\nFor boxes bevelled: flat faces n-gons/6+? bevelled cube: original faces become smaller quads? Original cube faces become n-gon with holes? No — bevel turns each face into a smaller quad-ish n-gon (still 4 corners but with chamfer corners: face becomes octagon? Actually bevel on cube: each original face becomes a smaller square (4 verts), corners become triangles/quads, edges become quads. With `segments=3`, corner patches. All faces small; smooth shading all with angle limit? Use `m.limit_method='ANGLE'` and shade all smooth + `harden_normals=True`? Without weighted normals, smoothing on box looks puffy. Keep boxes flat-shaded with bevel — crisp machined look; bevel highlights still appear (flat faces + bevel facets = fine, slight faceting on 3-seg bevel acceptable; use segments=2 flat? facet lines visible at grazing. Acceptable).\n\nActually nicer: after bevel on boxes, set bevel `segments=3`, and shade smooth only faces with normal similar... overkill. Flat shading fine for product look with small bevels.\n\nStrut skin+subsurf: shade smooth all.\n\nMembrane: smooth.\n\nCurve cables: smooth by nature.\n\nGLB export: The harness exports GLB itself? \"an interactive 3D scene exported to GLB\" — the benchmark handles export from saved scene; my script should just build scene + save .blend? The harness runs the script then does capture/export. The instructions: \"save a complete scene\". I should call `bpy.ops.wm.save_as_mainfile(filepath=...)`? Harness probably saves after script, or expects script to save? \"Make the important requirements evident in the published result, save a complete scene\" — I'll save to a path like `/tmp/robot_arm.blend`? Risky unknown env; maybe harness saves automatically. Hmm. Typical Blender-Bench harness: script runs, then harness saves scene & renders. To be safe, save mainfile to a sensible path derived from `bpy.path.abspath(\"//\")`? If unsaved blend, `//` = cwd. I'll do `bpy.ops.wm.save_as_mainfile(filepath=bpy.path.abspath(\"//robot_arm_scene.blend\"))` wrapped in try/except so it can't crash the run. Also set render settings (engine CYCLES, resolution 1536, samples 64, denoise on) as good defaults; benchmark overrides anyway.\n\nAlso set camera as scene camera, set unit scale metric.\n\nRender settings: engine 'BLENDER_EEVEE_NEXT' vs CYCLES: set CYCLES; if no GPU headless, fine, they override. Set samples 64, use_denoising True, resolution 1536x1536, film transparent False.\n\nSet world background: nodes, color (0.06?) Let me choose world strength 0.4, color (0.75,0.75,0.78)*? That yields gray ~0.3 in AgX. Nice.\n\nGround plane material: Principled base (0.82,0.81,0.79), roughness 0.55. Desk: (0.72,0.70,0.67) rough 0.45? Or white laminate (0.85). Desk slightly darker than floor for separation. Add subtle desk edge chamfer.\n\nNow write the strut function carefully:\n\n```python\ndef optimized_strut(name, A, B, dA, dB, rA, rB, v_axis, n=10, bend=0.012, x_bays=(4,), membrane_bays=(2,3,6), hub_embed=0.0):\n    A=Vector(A); B=Vector(B)\n    u=(B-A); L=u.length; u.normalize()\n    v=Vector(v_axis).normalized()  # lateral\n    w=u.cross(v).normalized()\n    v=w.cross(u).normalized()  # orthogonalize\n    prof=lambda t: 0.6+0.55*abs(math.cos(math.pi*t))**0.75\n    def rad(t): base=rA+(rB-rA)*t; return base*(1.28-0.5*math.sin(math.pi*t))\n    verts=[]; \n    tops=[]; bots=[]\n    for i in range(n+1):\n        t=i/n\n        C = A + u*(L*t) + w*(bend*math.sin(math.pi*t))\n        h = (dA+(dB-dA)*t)/2*prof(t)\n        T = C + w*h; D = C - w*h\n        tops.append(len(verts)); verts.append(T)\n        bots.append(len(verts)); verts.append(D)\n    edges=[]\n    for i in range(n):\n        edges.append((tops[i],tops[i+1])); edges.append((bots[i],bots[i+1]))\n    edges.append((tops[0],bots[0])); edges.append((tops[n],bots[n]))\n    for i in range(n):\n        if i%2==0: edges.append((tops[i],bots[i+1]))\n        else: edges.append((bots[i],tops[i+1]))\n    # extra X at middle bay\n    mid=n//2\n    edges.append((tops[mid], bots[mid+1])); edges.append((bots[mid], tops[mid+1]))\n```\n\nWait — zigzag already covers each bay with one diagonal; adding the second diagonal on the middle bay makes an X there. Ensure not duplicate edge: zigzag for bay i adds one of the two diagonals depending parity; adding both for mid bay — one may duplicate existing edge → duplicate edges in mesh from_pydata cause error? Duplicates get merged? from_pydata may create invalid geometry with duplicate edges — safer: compute set of diagonal keys, then ensure both diagonals of mid bay included:\n\n```python\ndiag=set()\nfor i in range(n):\n    if i%2==0: diag.add((tops[i],bots[i+1]))\n    else: diag.add((bots[i],tops[i+1]))\ndef key(a,b): return (min(a,b),max(a,b))\ndiag.add((tops[mid],bots[mid+1])); diag.add((bots[mid],tops[mid+1]))\nedges += [tuple(e) for e in {key(*e) for e in diag}]\n```\n\nAlso maybe add small mid-node knuckles? skip.\n\nRadii per vertex: for i,t: rt = rad(t); assign both top/bottom nodes radius (rt*1.15 for swollen nodes?). Skin radius units are absolute scale factors relative to object scale (radius multiplies by... skin radius default (0.25,0.25) relative in object units: actual radius = skin radius value in object local units). So set radius = (rt, rt).\n\nBranch swelling: at nodes where diagonals meet, skin naturally bulges.\n\nMesh create:\n```python\nme=bpy.data.meshes.new(name)\nme.from_pydata([v[:] for v in verts], edges, [])\nob=bpy.data.objects.new(name, me); collection.link(ob)\nsk=ob.modifiers.new('skin','SKIN')\nsv=me.skin_vertices[0].data\nfor i,d in enumerate(sv): d.radius=(radii[i],radii[i])\nsv[0].use_root=True\nsub=ob.modifiers.new('sub','SUBSURF'); sub.levels=2; sub.render_levels=2\nsmooth polys\n```\n\nNote: skin_vertices layer appears only after modifier added — order: create mesh w/o skin data; add modifier; then access me.skin_vertices. I believe adding Skin modifier creates the data layer. Yes (this is the standard scripting pattern).\n\nSubsurf on skin result: skin output is quads — good.\n\nMembrane panel for bay i (between node i and i+1): corners T_i, T_{i+1}, D_{i+1}, D_i. Inset factor 0.1 toward centroid. Build grid 6x6: point(s,r) bilinear interpolation of inset corners + normal offset bow*4*s*(1-s)*r*(1-r)... normal = v (lateral) — but which side? Film spans the bay like a window: lies in the u-w plane; normal = ±v. Bow outward +v*0.0025? On a planar beam, film covers one face (+v) — but then the other face (-v) open. Could add both faces for select bays (sandwich) — \"panels spanning openings within the struts\". A panel across the opening (in plane of rails) reads as covering the hole like a drum on each side, or a single mid-plane membrane inside. I'll place panels at mid-plane (the v=0 plane, since bay lies in plane through v=0 anyway — rails are at ±w, so bay plane is the strut mid-plane). A film stretched across the opening in the mid-plane with slight bow — reveals both sides, structure (rails+diagonal) borders it. \n\nPanel grid:\n```python\ndef quad_panel(name, P00,P10,P11,P01, normal, mat, bow=0.003, nx=8, ny=8, thick=0.0012):\n    verts=[]; faces=[]\n    for j in range(ny+1):\n        s=j/ny\n        for i in range(nx+1):\n            r=i/nx\n            top=P00.lerp(P10,r); bot=P01.lerp(P11,r)?? careful mapping\n```\nLet P00=D_i? corners order: c00=bottom_i? Let's define A_=T_i,B_=T_{i+1},C_=D_{i+1},D_=D_i. Bilinear: p = (1-r)(1-s)A + r(1-s)B + r s C + (1-r)s D. Bow: + normal*bow*sin(pi r)*sin(pi s). Inset: first inset corners toward centroid by 12%.\n\nSolidify modifier thickness 0.0011, offset 0. Subsurf level 2 on grid? grid 8x8 dense enough; add Subsurf 1 for silk smooth? 9x9 verts with sin bow already smooth. Skip subsurf; shade smooth; solidify (with even thickness). Solidify on grid w/o rim issues fine.\n\nAlso membrane needs to visually \"attach\": inset leaves gap to rails — floating? Inset 0.06 small gap; at render distance fine, plus could add tiny edge frame: skip, small inset (0.05) reads as bonded film. Actually overlapping rails slightly better (no gap): inset 0.0 → film edges under rails; rails radius ~0.008-0.01 cover the seam. Use inset 0.02 and bow 0.003.\n\nMembrane material: Principled BSDF: base_color (0.75, 0.82, 0.88), roughness 0.32, metallic 0.0, transmission weight 0.9, IOR 1.38, alpha 1. Also `coat` 0.2? Fine. In Cycles, thin transmission shows structure behind. Slight blue-gray tint. Maybe add subtle procedural bump via Noise→bump for mesh texture (\"fine architectural mesh\")? Procedural noise bump scale 300 detail 2 strength 0.15 — fine mesh feel. GLB bakes maybe; ok.\n\nActually careful: transmission 0.9 with roughness 0.32 may look like glass; TPU film ≈ glass-like — good. Tint slightly warm-smoke (0.8,0.83,0.85).\n\nCables helper:\n\n```python\ndef cable(name, points, radius, mat):\n    cu=bpy.data.curves.new(name,'CURVE'); cu.dimensions='3D'\n    sp=cu.splines.new('BEZIER'); sp.bezier_points.add(len(points)-1)\n    for bp,co in zip(sp.bezier_points, points):\n        bp.co=co; bp.handle_left_type='AUTO'; bp.handle_right_type='AUTO'\n    cu.bevel_depth=radius; cu.bevel_resolution=3; resolution\n    ob=...\n```\n\nCable paths:\n1. Base→turret internal: tiny loop from turret back to base top — points around J1? Represent as short cable from motor cap (J2 motor rear) down to turret top port: pts from motor end (y=-0.108,z=0.165) curving to (−0.03, −0.05, 0.105). \n2. Link1 cable: from turret top port (x=-0.02,y=-0.03,z=0.105) to elbow motor (E + (0,0.045,0)): route along inner side of link1: offset = -w*0.045 - v*0.02 from centerline at t=0.15,0.5,0.85 plus endpoints. With AUTO handles gives smooth hug.\nHmm keep cables on the -Y side (back from camera?) Camera at -Y: front is -Y side. Cables visible = good detail; place along -Y side slightly, neat. Clips: small boxes at t=0.3,0.6 positions.\n3. Link2 cable: elbow motor top → wrist motor: similar along link2 inner side (-w2).\n4. Servo cable wrist→gripper: short along tool body.\n5. Controller box → base: desk-level curve from box front to base plate rear... base at origin; box at (-0.18, 0.16): path along desk: [(-0.13,0.14,0.012),(-0.06,0.10,0.006),(-0.02,0.05,0.004),(0,0.03,0.008)] into base side port at (0,0.045,0.02)? Base r=0.062; port at y=+0.05? Let controller be at (-0.18,-0.16) front-left? Camera front -Y: controller front-left visible. Path neat S-curve.\n\nKeep total cables modest.\n\nSmall clips: torus clips around strut rails? Simplify: clip = small box on inner rail node position holding cable: place at t positions, box dims (0.012,0.014,0.008) oriented to u/v/w. 2 clips per link.\n\nStatus LEDs: tiny emissive cylinders (r 0.0025 depth 0.002) on elbow cap, wrist, turret front, gripper body. Green (0.1,1,0.3) emission strength 4. On -Y faces (camera side).\n\nBolts: hex heads: cylinder verts=6 radius r, depth; plus shaft? just head + washer face. Bolt ring helper creates n bolts on face plane given center, axis, ring radius: each bolt axis = axis. Hex orientation random rotate for realism (align same).\n\nMaterials list:\n- mat_titanium (struts): (0.62,0.63,0.65) metallic 1.0 rough 0.34\n- mat_alu (housings): (0.75,0.76,0.78) metallic 1.0 rough 0.22\n- mat_alu_dark: (0.16,0.17,0.19) metallic 0.95 rough 0.3 (anodized dark)\n- mat_steel (pins/bolts): (0.45,0.46,0.48) metallic 1 rough 0.18\n- mat_accent (orange anodized): (0.85,0.30,0.05) metallic 0.9 rough 0.28\n- mat_pad (urethane amber): (0.9,0.45,0.08)? pads maybe dark rubber (0.06,0.06,0.06) rough 0.7; choose amber urethane translucent-ish: base (0.85,0.4,0.05) rough 0.5 — reads replaceable pad.\n- mat_cable: (0.012) rough 0.55\n- mat_membrane as above\n- mat_desk: (0.80,0.79,0.76) rough 0.4\n- mat_floor: (0.55,0.55,0.56)? Floor slightly darker gray than desk for contrast; rough 0.5.\n- mat_object: machined aluminum + accent ring\n- mat_box (controller): dark (0.05,0.05,0.06) rough 0.4 metallic 0.2\n- mat_led_green emission\n\nWorld: nodes Background strength 0.5 color (0.6,0.62,0.66)? Grayish cool. Hmm with AgX, 0.6*0.5=0.3 → mid gray. Good.\n\nAlso add a big soft gradient? skip.\n\nExtra realism: joint stop tab on shoulder: small box on cheek inner + on link1 hub? skip—minor.\n\nNaming all objects nicely.\n\nObject count moderate. Let's also add subtle screw heads on desk base plate corners: 4 hex bolts at (±0.07,±0.07) on plate.\n\nGripper rails plates etc. — ensure no intersection with object: fingertips around (0.473,±0.014,0.042) vs object at (0.478,0) head r 0.009 z up to 0.036: finger plates inner faces at y=±(0.014-0.00225)=±0.01175 → gap to head surface (r0.009→ y extent ±0.009) = 2.75mm. \n\nWait: also check finger plate height in w3: 0.014 centered at GP+u3*0.037 — plates extend along u3 from GP+u3*0.012+... let me define finger plate: start at s=0.014 (from GP along u3) end s=0.062; center s=0.038; length 0.048. Pad at s=0.056..0.066? pad length 0.012 centered s=0.060: pad world pos = GP + u3*0.060 ± ... pad height (w3) 0.012, thickness Y 0.004 inner at y=±0.010 → inner faces at ±0.008 — hmm pads closer to center than plates? For parallel gripper pads inner faces at y=±0.0105 (pad thickness 0.003): gap between pads 0.021 > object head diameter 0.018 → 1.5mm/side. ok.\n\nPad world z: GP = W + u3*0.048 = (0.435+0.0160, 0, 0.150-0.0452)=(0.451,0,0.1048). Pad center = GP + u3*0.060 = (0.451+0.0200,0,0.1048-0.0566)=(0.471,0,0.0482). Pad height 0.012 along w3 (mostly vertical) → z 0.0422..0.0542. Object head top 0.036. So pads hover ~6mm above head — reads as approaching/aligning before descent. Acceptable mid-reach. Could lower wrist: reduce W z to 0.135 & aim steeper: u3 angle -78°: fingertips z ≈ 0.135-0.117=0.018 too low maybe collide pads with desk? pad bottom 0.018-0.006=0.012 ok... Let me keep some clearance: W=(0.435,0,0.145), u3 = u2 rotated -30°. I'll compute in code and clamp object under fingertips: object at fingertips + u3*0.025 projected to desk (x,y), z on desk. Then visual gap = distance from pads to object top along -u3... object height 0.036. Choose numbers to make pads ~8-12mm above object top — \"poised\". Fine.\n\nSimpler: I'll compute F = W + u3*0.115 (fingertip s=0.115? earlier 0.11). Then object_center_xy = (F + u3*0.02) with z=0 projection: obj_x = F.x + u3.x*0.02, obj_y = 0. Place object there. Good.\n\nDouble-check elbow/wrist angles plausible (< 150°): fine.\n\nAlso J1 rotation: arm oriented toward +X; turret rotates about Z — show slight rotation? Keep 0 (facing +X), camera at -Y sees side profile... 3/4 view better: rotate whole arm assembly about Z by -12°? Instead put camera at (1.05,-1.15,0.6) → sees front-right? +X is right side of frame when viewed from -Y. Camera at y=-1.15, x=1.05 looks toward origin: sees arm from front-right 3/4. Object at x≈0.47 closer to camera (x 0.47 vs base 0) — good depth. Gripper pads gap visible from this angle? Pads separate along Y; camera mostly along -Y → sees one finger behind other... Camera direction from (1.05,-1.15,0.62) to (0.2,0,0.2): d=(-0.85,1.15,-0.42) — significant Y component → sees XZ plane mostly; finger separation along Y appears as depth offset — partially visible. To show two fingers clearly, camera should have more side angle (along ±X? fingers separate along Y, tool axis in XZ plane; viewing along tool axis shows gap). A 3/4 from front-right shows fingers slightly. Also GLB orbit shows all. Add slight Y offset to camera target and keep camera x moderate: cam (0.95,-1.35,0.62), target (0.22,0,0.18). Fine.\n\nActually, maybe rotate entire robot about Z by +18° so the reach direction points slightly toward camera-left? Hmm keep axis-aligned for cleanliness; camera 3/4 handles depth.\n\nNow, membrane normal: ±v (Y). Film in mid-plane: bow along v*0.003.\n\nLet me also double-check skin modifier radius interplay with subsurf: typical pattern works.\n\nOne more requirement: \"recessed cable guides\" — the clips serve. Also maybe a spiral conduit on J1? skip.\n\nEnd effector actuation: add tiny linkage rods: from servo bottom (GP + w3*0.008) to each finger plate mid-top: thin cylinders r=0.0018 — with fingers at ±y the rods would angle — draw from servo to y=±0.014 plate tops. Compute rod endpoints: P1 = GP + u3*0.010 + w3*0.014 (servo tip), P2a = GP + u3*0.030 + w3*0.009 + v*0.014, P2b mirrored. Cylinder between points helper `rod_between(p1,p2,r,mat)`.\n\nAlso add visible pivot pins on fingers: at s=0.020 through carriage axis w3 r=0.003 length across 0.02 with cap discs.\n\nAlso gripper body: end plates at y=±0.022 holding rails: boxes (0.024 x? ) oriented frame: dims along (u3,v,w3) = (0.026, 0.004, 0.020) at GP+u3*0.012 ±v*0.022.\n\nRails: rods axis v from y=-0.022..0.022 at s=0.012, w3 offsets ±0.0065.\n\nCarriages: boxes dims (0.012,0.010,0.016) at s=0.012, y=±0.014.\n\nFingers plates: dims (0.048,0.0045,0.013) center s=0.038, y=±0.014, plus a 45° taper? keep straight with bevel 0.002.\n\nPads: dims (0.012,0.003,0.011) center s=0.058, inner y=±(0.014-0.00225+0.0015)= attach to plate inner face: plate inner face y=±(0.014-0.00225)=±0.01175; pad center y=±(0.01175-0.0015)=±0.01025. Pad slightly proud inward. Also pad face grooved? skip.\n\nWait fingers should extend from carriages at s~0.012 forward; root overlaps carriage: plate starts s=0.014 ends 0.062 — pad at s 0.052..0.064 beyond plate end? pad center s=0.058 length 0.012 → 0.052..0.064; plate ends 0.062. Fine.\n\nAlso small stop block between carriages? skip.\n\nGripper total from W: flange at s=0.042..0.048 (r0.02 disc), body s=0.048..0.048+0.036? Body center GP at s=0.048+? Let body span s 0.046..0.082: center s=0.064, dims u3 0.036. Redefine GP_body = W + u3*0.064. End plates at s=0.078? Rails at s=0.076 (front portion) spanning y; carriages at s=0.076; fingers from s=0.078 to 0.126; pads center s=0.122. Fingertip s≈0.128. W to tips = 0.128.\n\nHmm earlier I planned tips at 0.115; recompute: W=(0.435,0,0.145), u3 = rotate u2 down by extra angle. Let me just compute in code: choose wrist W, compute u2=(W-E)/|.|; u3 = rotate u2 about Y by -δ (δ=28° more downward). F = W + u3*0.128. Ensure F.z ≈ 0.035-0.045. u2 angle θ2 = atan2(u2.z, u2.x). With E=(0.2229,0,0.3657) W=(0.435,0,0.145): Δ=(0.2121,-0.2207), θ2=-46.1°, L2=0.3061. u3 angle = -74.1°: u3=(0.2735,0,-0.9619). F = W + 0.128*u3 = (0.435+0.0350, 0, 0.145-0.1231) = (0.4700, 0, 0.0219). Pad center s=0.122: z = 0.145-0.1173=0.0277; pad bottom ≈ 0.0277-0.0055=0.022. Object height must be < 0.02 to fit under pads?? Then object too short. Reduce reach: tips should hover ~0.045: choose W=(0.425,0,0.165): Δ from E=(0.2021,-0.2007) θ2=-44.8° L2=0.2848. u3 angle -72.8° (δ=28°): u3=(0.2956,0,-0.9553). F=W+0.128u3=(0.4628,0,0.0427). Pads z center=0.165-0.1166=0.0484, bottom ~0.043. Object: place under F + u3*0.02 → x=0.4687, top of object ~0.036 (height 0.036) → gap pads-to-top ≈ 0.043-0.036=0.007. \n\nObject: base puck r0.02 h0.006 (z0..0.006), neck r0.012 h0.014 (0.006..0.020), head: rounded knob r0.013 h0.016 (0.020..0.036) with torus ring accent at z0.028, hex top? Make it a \"machined demo part\": like a chess-pawn-ish precision weight: stepped. Top: small hex socket recess? skip recess. Head widest r 0.013 → y extent ±0.013 > pads gap (inner faces at ±0.01025)! Pads would clip head if closing, but they're 7mm above it — no intersection since pads z 0.043..0.054 vs head top 0.036. OK visually \"about to grasp the head\". But plates at y ±0.014 with plate z range: plate center s=0.102 → z=0.165-0.0975=0.0675, plates from s=0.078..0.126 → z from 0.0905 to 0.0446. Plates beside object head: head top 0.036 < plate bottom 0.0446 — no overlap. Good, zero intersections.\n\nThen fingers hover 8mm above object — mid-reach ✓.\n\nObject also add knurl? Add thin torus grooves ×2 on head. Fine.\n\nLet me now also design turret/cheek geometry to avoid intersection with link1 at 48°: cheeks at y=±0.043, plate dims x0.06 z from 0.10..0.19: link1 hub r0.026 at A1=(0,0,0.165) between cheeks (gap y ±0.036..? cheeks inner faces at y=±(0.043-0.007)=±0.036; hub depth along v? hub is cylinder along u1 with r 0.026 — its circular section passes between cheeks ✓ (0.026<0.036).\n\nBase cabling: cable1 from J2 motor rear cap (y=-0.106? motor on -Y side) down into turret top at (-0.03,-0.03,0.105): points: [(0,-0.112,0.165),(0.0,-0.10,0.13),(-0.01,-0.06,0.108),(-0.02,-0.03,0.104)]. Hmm motor cap at y=-0.106 centered x0 z0.165. Port on turret top: small cylinder at (-0.025,-0.03,0.10) r0.006. OK.\n\nLink1 cable: start at turret top port2 (0.02,-0.035,0.105)? route along -v side (front? v=Y; camera -Y so -Y side faces camera: cables visible → good \"controlled routing\" showcase). Actually camera sees -Y faces; put cables at y ≈ -0.03..-0.045 hugging inner underside of link1: offset -w1*0.05? w1 = u1 × v → u1=(0.743,0,0.669); v=(0,1,0); w1=u1×v = (0*0-0.669*1, 0.669*0-0.743*0, 0.743*1-0*0) = (-0.669,0,0.743). w1 points up-back. Inner side (toward desk front, below beam) = -w1 = (0.669,0,-0.743) (down-forward). Cable under beam: positions p(t)=S+u1*(L1*t) - w1*0.055 + v*(-0.028). At t=0.18,0.5,0.82 plus start near turret (S - w1*0.0 + v*(-0.03) z0.11...) and end near elbow motor (E + v*(-0.05) + w? elbow motor on -Y side too: motor center y=-0.06: cable end at E + (0,-0.055,0)+ u? Put end (E + v*(-0.062) - u2*0.0 ) i.e., at motor cap. Motor cap at y=-0.0825 end. Set end point = E + v*(-0.085) - w1*0.0 → but motor at elbow axis: fine (E.x, -0.085, E.z).\n\nClips at t=0.3, 0.62: small dark box straddling cable to beam: center at p(t)+ w1*0.02 dims small oriented frame(u1,v,w1). \n\nLink2 cable: from elbow motor top (E + v*(-0.085) + w? ) hmm same motor continues: start (E + v*(-0.085) + w2*0.01)?? Simply start at elbow encoder cap front (E + v*(-0.045) + w2*0.0) then along link2 underside: q(t)=E+u2*(L2*t) - w2*0.042 + v*(-0.024), t=0.2,0.55,0.85, end at wrist motor (W + v*(-0.038)). w2 = u2×v: u2=(0.709,0,-0.705)?? compute: u2 = Δ/L = (0.7094,0,-0.7048). w2 = u2×v = (u2.y*0 - u2.z*1, ..., u2.x*1) = (0.7048, 0, 0.7094). -w2 = down-back. Cable offset -w2*0.04 (below beam) + v*(-0.024). OK.\n\nWrist→servo cable: from wrist motor cap (W + v*(-0.05)) to servo (GP_body + w3*0.02 + v*(-0.008)): points: [(W+v*(-0.048)+w2*0.0), (W+u3*0.03+v*(-0.03)+w3*0.01), (GP_body + w3*0.016 + v*(-0.01))]. Short.\n\nController cable: controller box at (-0.20,-0.14) top z0.03; cable from box front port (−0.155,−0.11,0.015) to base rear port: base at origin r0.062 — rear from camera = +Y? camera at -Y: rear = +Y (hidden). Visible routing along desk front: path pts: [(-0.16,-0.115,0.014),(-0.10,-0.09,0.006),(-0.05,-0.075,0.005),(-0.02,-0.06,0.006),(0.0,-0.055,0.012)] end into base side at (0,-0.062,0.02)? base cylinder r 0.062 at y=-0.062 → point (0,-0.060,0.02). Slight S-curve, tidy. Port grommet small cylinder at (0,-0.058,0.02) axis Y.\n\nAlso small grommets where cables enter ports: tiny dark cylinders.\n\nController box: rounded box 0.10×0.07×0.032 at (-0.20,-0.14,0.016)+? sitting on desk: center z=0.016. Top: small recess + LED dot green + tiny label plate (0.05×0.02×0.002 alu). Bevel 0.006.\n\nNow base plate bolts at corners (±0.068,±0.068, plate top z0.014): hex bolts r0.0045 h0.005 + washers r0.0065 h0.001.\n\nBearing rings detail: between turret and lower base: orange accent ring torus? Use thin cylinder r0.057 h0.0025 accent at z 0.0585. And dark ring r0.056 h0.01 z0.052.\n\nShoulder bearing caps: cylinder axis Y r0.030 depth0.012 at y=±0.0560? cheek outer face at y=±0.050 (cheek y dim 0.014 centered ±0.043 → outer ±0.050). Cap center y=±0.056 → spans 0.050..0.062. Cap bolts: 4 small hex on cap face ring r0.022. Pin end nuts at y=±0.065: hex r0.009 depth 0.008.\n\nElbow caps r0.022 at y=±(0.032+?) cheeks2 y dim 0.010 centered ±0.030 → outer 0.035; cap center ±0.041 depth0.010. Pin r0.007 nuts ±0.048. Motor2 on -Y: housing r0.020 depth 0.05 center y=-0.060 (spans -0.035..-0.085) + cap r0.021 depth 0.006 at -0.088, LED on cap? LED on cap facing -Y at (E + (0,-0.092,0)). \n\nWrist: housing block axis Y r0.017 depth0.046 center W; caps r0.013 y=±0.026 depth0.008; pin r0.005; motor3 r0.013 depth0.035 center y=-0.0415 (spans -0.024..-0.059) cap at -0.061.\n\nRoll actuator: cylinder axis u3 r0.015 depth 0.034 center s=0.017 (from W) → spans 0..0.034. Collar accent ring at s=0.036 r0.0155 depth0.003. Flange disc r0.019 depth0.006 center s=0.041. Flange bolts 4× r0.0022 on face ring r0.014 at s=0.0445 facing +u3. Gripper body starts s=0.047.\n\nGripper body: center s=0.065 dims (u3:0.036, v:0.040, w3:0.024) bevel0.004 dark alu. Servo: on +w3 face at s=0.058: cylinder axis w3 r0.0085 depth0.018 center offset w3*(0.012+0.009)=0.021 → from body top face 0.012 to 0.030. Servo cap + tiny cable.\n\nRails at s=0.080: rods axis v r0.0028 length 0.048 centers GP80 = W+u3*0.080 ± w3*0.0065. End plates at s=0.080, y=±0.024 dims (0.020,0.004,0.018). Wait rods length 0.048 → y ±0.024 exactly reaching plates ✓. But rods pass through body front? body spans s 0.047..0.083 v ±0.020: rods at s=0.080 inside body region (s<0.083) and |y|>0.020 outside body v-range → rods ends visible, middle hidden inside body. Rods r0.0028 at y±0.024 → just outside body ±0.020 ✓.\n\nCarriages at s=0.080 y=±0.0135 dims (0.014,0.009,0.015) bevel0.002 — carriage slides on rods; rods at y±0.024... carriage at 0.0135 not on rods. Move rods y span smaller: plates at y=±0.018, rods length 0.036 (y±0.018) at w3 offsets ±0.0065, carriages at y=±0.0135 width 0.009 → spans 0.009..0.018 riding rod ends? Rods pass through carriage: carriage v-extent 0.009..0.018, rods at w3 ±0.0065 within carriage w3 extent (±0.0075) ✓. So rods thread carriage. Fingers at y=±0.0135. Pads inner faces: plate thickness v 0.0045 → inner face y=±0.01125; pad center ±0.00975 thickness0.003 → inner faces ±0.00825, gap 0.0165 vs object head r0.013?? gap diameter 0.0165 < head dia 0.026 — pads above head anyway (no collision); but visually \"open gripper wider than object\" reads better: increase finger y to ±0.017: carriages ±0.017 (span 0.0125..0.0215) — body v half 0.020 → carriage edge 0.0215 slightly outside body — fine (slides proud). End plates at y=±0.022, rods length 0.044 (±0.022) thread carriages ✓. Pads inner faces at ±(0.017-0.00225-0.0015)=±0.01325 → gap 0.0265 ≈ head dia 0.026 — perfect poised-to-close look.\n\nFingers plates: center y=±0.017 dims (0.046,0.0045,0.012) s from 0.084..0.130 (center s=0.107). Pads center s=0.124 dims (0.012,0.003,0.010) y=±0.01525. Fingertips s=0.130. Pad bottom z: W.z + u3.z*0.124 - 0.005 ≈ 0.165-0.1185-0.005=0.0415 ✓ above object top 0.036, gap 5.5mm ✓.\n\nPivot pins: at s=0.090 axis w3 r0.0032 depth across y? Pivot visible on outer face of carriage: cylinder axis v r0.0032 depth 0.011 at y=±0.017 (through carriage) with cap disc r0.0045 at outer y=±0.0217. ✓ \"visible pivots\".\n\nLinkage rods: from servo nose (s=0.058, w3*0.030 → point P1 = W+u3*0.058+w3*0.030, v0) to finger top (s=0.100, y=±0.017, w3*0.008): P2 = W+u3*0.100 + v*(±0.017) + w3*0.008. rod r0.0016 steel. Two rods angled — believable sync linkage.\n\nAlso small gusset plates on gripper body front connecting rails? fine as is.\n\nAlso add wrist tool-side encoder disc: at s=0.0 (W) ring r0.018 dark on block ✓ already housing.\n\nAdd joint rotation axis indicator: thin orange line torus around caps? Accent ring torus around each bearing cap: torus major r=cap_r, minor 0.0012 accent at cap outer face — subtle design language consistency. Add for shoulder, elbow, wrist caps on camera side (-Y) only? Add both sides, cheap.\n\nNow LINK HUBS & flanges:\n- Link1 root hub at A1: cylinder axis u1 r0.026 depth0.055 center A1+u1*0.010 → spans -0.0175..0.0375 along u1 from A1. The J2 pin passes through A1 (z0.165) — hub around A1 ✓. Flange ring r0.030 depth0.006 at A1+u1*0.030? Hub bolts: 4 bolts on a face ring... Strut starts at s0=0.030 from A1 to E-hub. Strut A = A1 + u1*0.032, B = E - u1*0.030. Hub2 at E: cylinder axis u1 r0.022 depth0.05 center E - u1*0.008 (spans E-0.033..E+0.017) r0.022. Elbow cheeks attach to link2 root — wait I set cheeks2 on link2 root around E. Hub for link2 root: cylinder axis u2 r0.020 depth0.055 center E+u2*0.008. Hmm hub1 (link1 end, axis u1) and hub2 (link2 root, axis u2) both near E with pin through E — hub1 spans to E+0.017 overlapping hub2 region... pin axis Y through E; hub1 r0.022 at E along u1, hub2 r0.020 along u2 — they'd intersect each other! Real design: link1 end = fork (clevis), link2 root = single eye between. So: link1 end hub: two cheek plates (fork) on link1: plates axis u1 at y=±0.030, dims (0.05 along u1, 0.010 y, 0.044 w) centered E - u1*0.010 → they wrap around E with pin at E. Link2 root eye: cylinder axis u2 r0.020 depth 0.048? eye center at E: cylinder along u2 centered E + u2*0.012, r 0.019, y-width? The eye needs v-thickness ≤ gap between fork inner faces (±0.025): make eye a flattened cylinder: use box? Use cylinder r0.019 along u2 then scale v 0.9? Simpler: eye = box oriented (u2,v,w2) dims (0.055, 0.036, 0.040) centered E+u2*0.012, bevel 0.010, with bore implied by pin passing through at E. The pin r0.007 through E spans y ±0.048: passes through fork plates (y ±0.030, outer 0.035) and caps at ±0.041. Eye box y ±0.018 between fork inner faces ±0.025 ✓ gap 7mm each side — add thrust washers: cylinders axis Y r0.012 depth0.003 at y=±0.020 centered E ✓ nice detail.\n\nSimilarly shoulder: link1 root hub r0.026 cylinder — but cheeks (fork) are on turret, hub is the eye: hub cylinder along u1 axis, needs v-width ≤ 0.072 (inner faces ±0.036): cylinder depth along u1 not v; its v-extent = r = 0.026 ✓ fine (circular cross-section passes between cheeks with clearance 10mm/side — add thrust washers r0.014 depth0.003 at y=±0.030, z=0.165).\n\nWrist: link2 end hub: cylinder axis u2 r0.016 depth0.045 center W - u2*0.006 → spans W-0.0285..W+0.0165; wrist block r0.017 axis Y at W with pin r0.005 through... link2 end = eye, wrist block = rotating yoke? Make wrist block the eye of link2's fork? Simplify: link2 end has fork plates (y=±0.022, dims (0.04,0.008,0.032) axis u2 centered W - u2*0.008); wrist block (axis Y cylinder r0.016 depth 0.036) sits between, pin r0.005 through W, caps r0.013 at y=±0.028. Thrust washers r0.009 at y=±0.0165. Roll actuator attaches to wrist block front face along u3: cylinder r0.015 from s=0.004.. — block r0.016 → actuator base inside block ✓.\n\nFork plates on link2 end vs hub: replace hub with the two fork plates + cross tube: add cross tube cylinder axis Y r0.013 depth 0.052 at W - u2*0.008 connecting plates (static part of link2) — pin for rotation separate r0.005. OK.\n\nAlso link1 root: add cross tube axis Y r0.020 depth 0.08 at A1 (through hub & cheeks) — the actual hinge pin is r0.011; cross tube = hub sleeve. Skip extra: hub cylinder already there; pin through.\n\nNow strut endpoints:\nLink1 strut: A = A1 + u1*0.034, B = E - u1*0.040 (hub1 region ends E-0.033). dA=0.080, dB=0.056, rA=0.0115, rB=0.0085, n=12, bend along -w1 (outward bulge down-forward): bend sign: use +w1? w1=(-0.669,0,0.743) up-back; bulge toward -w1 (down-forward) looks like a bone sagging → organic: bend=-0.014 (applied as w*bend*sin → -w1 dir). Choose bend=+0.010 along +w1 (arching up-back)? Topology-optimized beams often bow against load — either fine; pick -0.012.\nLink1 length ~0.30-0.074=0.226 actual strut span ~ (E - u1*0.040) - (A1+u1*0.034): L_total 0.3061? A1=(0,0,0.165), E=(0.2229,0,0.3657) → |SE| = 0.30 (by construction L1=0.30). Strut span = 0.30-0.074=0.226.\n\nLink2 strut: A = E + u2*0.034, B = W - u2*0.036. span = L2 - 0.07 = 0.2848-0.07=0.215. dA=0.052, dB=0.034, rA=0.0080, rB=0.0058, n=11, bend -0.010.\n\nMembrane bays link1: bays [2,3, 7,8]? Choose 2 panels: bays 3 and 8 (0-indexed between nodes). Link2: bay 4. Also maybe one more on link1 bay 5? Leave X-braced middle bay open (shows lattice). Good: membranes at link1 bays 3,8; link2 bay 4.\n\nPanel corners from strut node positions — need the node coordinates; have strut function return node positions (tops,bots, and frame) for membrane & cable clip placement. \n\nAlso small collars where strut meets hubs: torus accent at strut ends? The swollen skin end nodes embed into hub cylinders — fine.\n\nNow small object \"machined\": \n- puck: r0.020 depth0.006 z0.003 alu\n- ring groove: torus accent r? skip\n- neck: r0.0115 depth0.014 center z0.013\n- head: r0.013 depth0.016 center z0.028, bevel 0.003 → total top 0.036\n- accent ring: torus major0.0125 minor0.0015 at z0.024 orange\n- top hex recess: hex cylinder r0.004 depth0.002 dark at z0.0365 embedded slightly? place top z0.0362 → looks like socket. Actually recess can't be boolean easily; fake with dark hex disc (reads as socket) ✓.\nPosition: obj_x = F.x + u3.x*0.02 = 0.4628+0.0059=0.4687 → (0.469, 0, ...). \n\nSecond small part: bearing: outer ring torus major0.009 minor0.0035 steel at (0.40, 0.11, 0.0035); inner torus smaller dark? plus few ball spheres r0.0018 ×6 around? cute detail: 6 chrome balls. Cheap, add.\n\nAlso a third tiny: washer torus r0.0045 minor0.0015 at (0.43,0.06). ok.\n\nDesk edge detail: add thin groove line on desk? skip.\n\nDesk lamp? Not needed; lighting is studio softboxes (invisible). But for orbit view, maybe add a physical softbox? No.\n\nFloor reflection: roughness 0.5 slight sheen.\n\nText/logo? skip.\n\nScene composition: also add a subtle backdrop wall panel behind desk at y=+1.4 for 2D render depth: plane 6×3 light gray at y=1.6? Camera FOV: from cam pos, background = world gray. Adding wall gives horizon line — cyclorama better. Let me build cyclorama: profile from floor (y=-2.5..1.2 flat) curving up at y=1.2..2.2 (radius 0.8) then vertical to z=3. Extruded along x -3..3. Build via mesh grid manually: sample profile points, create faces. Material same as floor or slightly lighter. This gives seamless studio sweep in main render; from orbit back views, you see the cove from behind (a curved shell) — acceptable, like a studio backdrop prop. Solidify not needed; give it thickness via Solidify modifier for orbit cleanliness.\n\nHmm, floor plane + cove overlapping: make cove floor section BE the floor (no separate plane) — cove extends y from -3 to vertical wall. Under desk region covered. Extend x ±4. Floor mat light gray. Desk stands on it.\n\nCamera & cove: cam at (0.95,-1.35,0.62)? Distance to target (0.22,0,0.18) = sqrt(0.73² + 1.35² + 0.44²)= sqrt(0.533+1.823+0.194)= sqrt(2.55)=1.597. Lens 58mm → vertical FOV 2*atan(18/58)=34.5° → frame height at target ≈ 2*1.597*tan(17.25°)=0.99 m. Scene height needed: from desk top (0) to elbow top 0.39 + margin, plus desk front edge below (z -0.05 at y=-0.5 → closer to camera, appears lower). ~0.6 m content vertical → fits with margin. Horizontal: arm x -0.1..0.55 (0.65) + base → fits 0.99 width easily. Maybe tighten: lens 65. Keep 60.\n\nDOF: focus distance ~1.55, f/6.3.\n\nAlso to ensure membrane transmission visible: lighting behind? rim light from +Y helps transmit. OK.\n\nNow write all code carefully with helpers. Watch out Blender 5.1 API details:\n\n- `bpy.ops.mesh.primitive_cylinder_add(radius=, depth=, vertices=, location=, rotation=)` — rotation as Euler; for axis alignment use quaternion.to_euler().\n- Materials: `mat.use_nodes=True`, nodes[\"Principled BSDF\"] inputs by name: 'Base Color','Metallic','Roughness','IOR','Alpha','Transmission Weight','Coat Weight','Emission Color','Emission Strength'. In 5.x emission input name 'Emission Color' ✓, transmission 'Transmission Weight' ✓.\n- World: `bpy.data.worlds.new`, use_nodes, Background node inputs 'Color','Strength'.\n- Color management: `scene.view_settings.look` — try 'AgX - Medium High Contrast'; wrap try.\n- Camera: `bpy.data.cameras.new`, lens, sensor_width; DOF: `cam.dof.use_dof=True; cam.dof.focus_object=empty; cam.dof.aperture_fstop=6.3`.\n- Lights: `bpy.data.lights.new(type='AREA')`, energy, shape='DISK'/'RECTANGLE', size.\n- Curve bevel.\n- Skin modifier: as discussed. One caution: `me.skin_vertices` requires modifier in stack; after `mod = ob.modifiers.new('Skin','SKIN')`, access `me.skin_vertices[0].data` — in some versions need `bpy.context.view_layer.update()` first. I'll add update call. Pattern widely used: works.\n- Subsurf modifier: `sub.subdivision_type='CATMULL_CLARK'`, levels.\n- Solidify for membrane.\n- Torus: `primitive_torus_add(major_radius=, minor_radius=, major_segments=48, minor_segments=12, location=, rotation=)` — torus axis default Z; align with axis via rotation.\n- Applying modifiers: use `bpy.context.view_layer.objects.active=ob; ob.select_set(True); bpy.ops.object.modifier_apply(modifier=...)`. To speed, could leave bevels unapplied (render fine, GLB exporter applies modifiers too). Leave modifiers unapplied! Less risk, faster. Render & export both evaluate. Keep bevel mods live. Only ensure normals fine.\n\n- For smooth shading selective: set polygons before adding bevel modifier: bevel output shading follows? Bevel faces inherit smooth? Bevel modifier has `segments` and produces faces with smooth shading derived from `harden_normals`/face smooth flags. With side faces smooth and caps flat on cylinders pre-bevel, result: bevel strips smooth — decent.\n\nActually simpler for cylinders: don't bevel small ones; bevel main housings. Set smooth sides via polygon loop.\n\nFor boxes: bevel modifier live, flat shading. Bevel on flat-shaded cube → bevel faces flat facets; with segments=3 visible faceting at close-up. Use segments=4 small width — ok.\n\nAlternatively shade box smooth + WeightedNormal modifier (exists in 5.1? \"WeightedNormal\" modifier still available in 4.x/5.x — yes, `NODES`? no, Weighted Normal modifier persists). I'll add WeightedNormal after Bevel for boxes with keep_sharp. If it errors, try/except pass. Hmm keep it: try/except.\n\nTime to also handle scene organization: put everything in one collection (default). Name objects semantically.\n\nRender engine: set 'CYCLES'. Also `scene.cycles.samples=64`, `scene.cycles.use_denoising=True`, resolution 1536. Device default; benchmark overrides. Set `scene.render.film_transparent=False`.\n\nAlso set `scene.render.image_settings.file_format='PNG'` and filepath? Not needed; benchmark renders. Skip filepath; save blend.\n\nUnit: `scene.unit_settings.system='METRIC'; scale_length=1.0`.\n\nLet me now write the geometry code in detail, computing frames.\n\nConstants recap (compute in code):\n```\nS = Vector((0,0,0.165))\na1 = radians(48)\nu1 = Vector((sin(a1),0,cos(a1)))\nL1 = 0.30\nE = S + u1*L1\nW = Vector((0.425,0,0.165))\nd = W-E; L2=d.length; u2=d/L2\ndelta = radians(28)\n# rotate u2 about Y by -delta (more downward): \nu3 = Vector(( u2.x*cos(delta)+(-u2.z)*sin(delta)?? ))\n```\nRotation about Y axis by angle φ: x' = x cosφ + z sinφ; z' = -x sinφ + z cosφ. Rotating u2 (which has negative z) further downward = rotate toward -z from u2... u2 angle θ2 = atan2(z,x) = -44.8°. Want θ3 = θ2 - 28°. So u3 = (cos(θ3), 0, sin(θ3)). Compute θ2 via atan2, then θ3 = θ2 - radians(28). Simple.\n\nv = Vector((0,1,0))\nw1 = u1.cross(v) → (u1.z*? ) compute: u1×v = (u1.y*v.z - u1.z*v.y, u1.z*v.x - u1.x*v.z, u1.x*v.y - u1.y*v.x) = (0*0 - u1.z*1, u1.z*0 - u1.x*0, u1.x*1 - 0) = (-u1.z, 0, u1.x) = (-0.669,0,0.743) ✓ up-back.\nw2 = (-u2.z, 0, u2.x) = (0.705,0,0.709) up-forward ✓.\nw3 = (-u3.z, 0, u3.x) = (0.955,0,0.296) ✓.\n\nFrames for oriented boxes: rotation matrix columns (u, v, w) → Matrix((u,v,w)).transposed() as 3x3 → to_4x4.\n\nHelper `place(name, obj_or_data...)`—I'll write:\n\n```python\ndef set_frame(obj, x, y, z, loc):\n    R = Matrix((x,y,z)).transposed().to_4x4()\n    R.translation = loc\n    obj.matrix_world = R\n```\nBut if object has un-applied scale (boxes set dimensions then apply scale before frame). For boxes: create cube, set dimensions, apply scale (bpy.ops.object.transform_apply) — need active object context; do before framing. Then set matrix_world.\n\nCylinder default along Z; frame with z-axis=u: set_frame(obj, x=v2?, y=?, z=axis). Provide orthonormal completion: given axis z, choose tmp = v(global Y) unless parallel; x = normalize(cross(tmp? )). For Y-axis cylinders: axis=(0,1,0): x = axis.cross((0,0,1))? Let me: given z_axis a: pick t = (0,0,1) if abs(a.z)<0.9 else (1,0,0); x = normalize(a.cross(t))? need orthonormal: x = normalize(t.cross(a))? Any consistent: \n```\nt = Vector((0,0,1)) if abs(a.z)<0.95 else Vector((1,0,0))\nx = a.cross(t).normalized()  # perpendicular\ny = a.cross(x).normalized()?? \n```\nCheck orthonormal right-handed: y = z.cross(x)? For matrix columns x,y,z with det +1: y = z × x. Set y = a.cross(x)? z×x = y by right-hand rule ✓ so y = a.cross(x).\n\nHmm a.cross(x) with x = a×t: a×(a×t) = a(a·t) - t(a·a) = a(a·t)-t → magnitude fine, direction = z×x ✓ correct.\n\nFor axis=Y: a=(0,1,0), t=(0,0,1): x = a×t = (1*1-0*0, 0*0-0*1, 0) = (1,0,0)? compute: a×t = (a.y*t.z - a.z*t.y, a.z*t.x - a.x*t.z, a.x*t.y - a.y*t.x) = (1*1-0, 0-0, 0-0) = (1,0,0). y = a×x = (0,1,0)×(1,0,0) = (1*0-0*0, 0*1-0*0, 0*0-1*1) = (0,0,-1). So cylinder Z→Y with x=(1,0,0), y=(0,0,-1) fine.\n\nMembrane panel builder returns object.\n\nRod between points:\n```python\ndef rod(p1,p2,r,mat,name,verts=16):\n    d=p2-p1; L=d.length\n    cyl at (p1+p2)/2 axis d/L\n```\n\nBolt ring:\n```python\ndef bolt_ring(center, axis, ring_r, n, br, bh, mat):\n    a=axis normalized; x,y basis\n    for k in range(n):\n        ang=2πk/n\n        p = center + x*(ring_r cos) + y*(ring_r sin)\n        hex bolt: cyl verts=6 radius br depth bh at p + a*(bh/2)?? \n```\nDecide bolt sits proud of face: center at face point + a*(bh*0.25) so embedded slightly. Add small washer disc under: cyl r=br*1.4 depth bh*0.3 at face+0.15bh. Keep both.\n\nBolts on faces with axis ±Y etc.\n\nLED: cyl r0.0025 depth0.0015 emissive mat + tiny dark bezel r0.0035.\n\nEmissive mat: Principled Emission Color (0.2,1.0,0.35), strength 6, base black.\n\nNow counts: bolts: base plate 4(+washers), turret plate 6, shoulder caps 8 (4/side small), hub collars? Let me include washers in bolt_ring by default.\n\nTotal objects maybe ~220 — fine.\n\nAlso to show \"replaceable interface plates\": at strut-hub junctions add collar plates: thin disc r=hub_r*1.08 depth 0.004 at hub-strut boundary + 4 micro bolts. Add for 4 hubs.\n\nAlso shoulder motor: cylinder r0.024 depth0.05 axis Y center (0,-0.081,0.165) + rear cap r0.025 depth0.006 center (0,-0.109,0.165) dark + LED? encoder disc on +Y cap instead. Add motor mounting flange r0.028 depth0.004 at y=-0.058.\n\nCheek top cover: rounded box over cheeks tops? cheeks at z up to 0.19; link passes... skip cover.\n\nMechanical stop: small block on cheek at angle limiting link1 backward motion: box (0.012,0.012,0.02) at (-0.035,-0.043,0.145)? hmm inside cheeks region between them is where hub moves; stop tabs on inner cheek faces behind hub: place small blocks at y=±0.033 (inner face ±0.036 minus half 0.0035), x=-0.030, z=0.150. Fine subtle.\n\nBase anti-slip ring under plate: thin dark disc r0.075 depth0.002 at z0.001? plate is 0.17 square; rubber ring torus major0.07 minor0.002 under? skip—plate on desk.\n\nAdd desk grommet? no.\n\nNow camera target empty + DOF empty.\n\nLights detail: \nkey = area, energy 800, size 0.9, loc (0.4,-1.1,1.7), rot toward target (0.25,0,0.2) — write point_light_at helper using rotation_difference on -Z (lights point -Z local).\nfill: energy 300, size 0.8, loc (-1.2,-0.5,0.8), color (0.85,0.90,1.0)\nrim: energy 700, size 0.5, loc (0.9,1.0,1.3) target (0.3,0,0.25) color (1.0,0.95,0.9)\ntop soft: energy 500 size 1.2 loc (0.1,0.2,2.2) target (0.2,0,0)\nAlso small area near gripper? skip.\n\nWorld strength 0.35 color (0.65,0.66,0.70).\n\nWith AgX medium-high contrast this should look premium.\n\nCheck membranes under Cycles: transmission needs `surface_render_method`? In 5.x, for transmission no alpha needed — works. Film thin w/ solidify ✓. IOR 1.38.\n\nGLB: transmission exported ✓.\n\nMembrane procedural bump noise — GLB bake might handle; keep subtle; actually risk of weird bake — keep bump very low (0.12) or skip? \"fine architectural mesh\" texture: use Noise scale 400 → bump strength 0.15 distance 0.0002. Fine, keep. Actually to reduce bake weirdness, keep it — benchmark says may bake supported procedural inputs; Noise→Bump→Normal is supported bake. OK.\n\nDesk material: slight noise bump? skip, clean laminate rough 0.4.\n\nFloor/cove: roughness 0.55.\n\nAlso add subtle imperfections to metals: Noise → roughness via ColorRamp tiny range (0.2-0.3)? Procedural noise scale 120 detail 2 → ramp → roughness. Keep simple: skip for robustness; set scalar roughness.\n\nActually crisp material separation is requested; plain scalar fine.\n\nOne more requirement: \"compact gearboxes\" — shoulder: add gearbox cylinder r0.034 depth0.03 axis Y at (0, 0.065, 0.165) on +Y side (opposite motor)? That's big vs cheeks outer 0.050 — mount on +Y outer face: center y=0.066 spans 0.051..0.081 r0.034 → around cap r0.030... overlapping cap; instead make +Y side the gearbox: replace cap on +Y with gearbox housing r0.032 depth 0.026 center y=0.063 + output flange. And -Y side: motor. Encoder small cap on motor rear. Do same pattern elbow (smaller): +Y gearbox r0.024 depth0.02 center y=0.047; -Y motor (already). Wrist: +Y side encoder cap r0.014; -Y motor.\n\nWait caps: I had caps both sides + nuts. Adjust: +Y: gearbox (shoulder), cap then at gearbox end: small cap r0.020 depth0.008 at y=0.080 + LED. Pin nuts both ends still fine at y=±0.085? Shoulder pin spans through everything y -0.115..0.085? Pin r0.011 from motor through to gearbox — pin visible between components? Pin hidden inside housings; show pin ends: extend pin to y=±0.088 with hex nuts at ends. Motor spans -0.056..-0.106 → pin inside motor invisible; nut at y=-0.112 on motor cap? Weird. Simpler: pin ends visible at gearbox front face (+Y) as bolted shaft collar: collar r0.014 depth0.006 at y=0.084 + center hex bolt r0.005. On -Y motor rear cap center hex r0.005. Reads as shaft clamps ✓.\n\nElbow: +Y gearbox r0.022 depth0.018 center y=0.046, collar r0.011 at y=0.057 hex r0.004; -Y motor r0.019 depth0.045 center y=-0.0585 cap r0.020 at -0.083, center hex. Encoder disc: thin dark cylinder r0.016 depth0.004 between motor and cheek? at y=-0.037. OK.\n\nWrist: +Y: encoder cap r0.013 depth0.010 center y=0.029, collar hex; -Y: motor r0.0125 depth0.030 center y=-0.038, cap.\n\nJoint axis visibility ✓ via pins/collars.\n\nLink1 root hub at A1 with cheeks — hub center A1+u1*0.008, r0.026 depth 0.06: spans A1-0.022..A1+0.038. Pin at A1 axis Y passes through hub ✓ (hub is cylinder around u1 through which Y-pin crosses — intersection geometry fine, cylinders overlapping okay visually as assembled).\n\nThrust washers shoulder: r0.013 depth0.003 axis Y at y=±0.0305 z0.165 — hub v-extent r0.026 at A1 → hub surface at y ±0.026 near A1... washers at ±0.0305 between hub and cheeks inner (±0.036) ✓.\n\nEverything plausible.\n\nBase rotation indicator: small index mark? skip.\n\nAlso add a subtle chamfer ring at hub-cylinder ends: torus? skip—bevel modifier on cylinders with width 0.002 covers edges. Bevel cylinders: add bevel modifier width ~0.0015-0.003 segments 3, angle limit. For small parts width 0.001.\n\nI'll add bevel param to cyl helper (default small) but skip applying; live modifiers.\n\nPerformance: ~250 objects each with bevel modifiers — Cycles fine.\n\nNow membrane bow direction ±v: choose +v? Film inside mid-plane with slight bow +v (toward camera back?) camera at -Y: +v bow faces away; slight, irrelevant. Use alternating bow per panel? Keep +0.0028 bow.\n\nAlso add tiny membrane edge frames? no.\n\nLet me also slightly tilt panels? no.\n\nDouble-check skin modifier usage in 5.1 — unchanged API I believe.\n\nSubsurf after skin: `sub.levels=2; sub.render_levels=3`? render 2 enough given small radii; 3 heavy. Use 2/2.\n\nSmooth shading for strut mesh: after from_pydata set all polys... skin mesh initially has no faces! from_pydata with edges only → no polys. Smooth shading applies to generated skin output: set via modifier? The Skin output polygons inherit... they may be flat → faceted tubes! Need smooth: after skin+subsurf, subsurf smooths normals? Subsurf produces smooth-ish shading only if faces smooth? Subsurf divides but shading flat per face unless smooth. To ensure smooth: add a \"Smooth by Angle\" via geometry nodes? Simplest: apply skin modifier, then set polys smooth, keep subsurf live. Applying skin: `bpy.ops.object.modifier_apply(modifier='Skin')` with context. Then set all polys smooth, then subsurf live. Skin result ~ (n=12 → verts maybe 300) fine.\n\nOrder: create mesh, add skin mod, set radii, apply skin, shade smooth, add subsurf. \n\nMembrane Solidify: live ok.\n\nCable curve bevel_resolution 3, resolution_u 12.\n\nEdge case: `me.skin_vertices` — after adding modifier, must ensure depsgraph update: call `bpy.context.view_layer.update()`. Then set radii; then apply modifier with ops (needs object active & selected in view layer — headless fine).\n\nAlternative safer: apply skin via evaluated mesh copy? Use ops straightforward; it's standard.\n\nAlso `use_root`: set on data vertex 0: `sv[0].use_root=True`? attribute exists: `SkinVertex.use_root` ✓. Also maybe needed `use_loose` no.\n\nOne concern: Skin modifier at branch nodes with 4 edges (middle X nodes have degree 4) — handles fine.\n\nRadii: skin radius tuple (rx, ry) equal.\n\nHub embed: strut end node radius rA*1.28=0.0147 vs hub r0.026 → embeds ✓. Elbow end 0.0085*1.28=0.0109 vs fork plates? link1 end has fork plates at y±0.030 + cross tube? I removed cross tube at elbow for link1; strut B = E - u1*0.040 with fork plates spanning E-0.035..E+0.015 along u1 → strut end embedded between plates region; add link1-end collar: cylinder axis u1 r0.020 depth0.045 center E-u1*0.030 — strut end node (r 0.0109) embeds into collar ✓ collar between fork plates (r0.020 < gap half 0.025) ✓.\n\nSimilarly link2 root eye box covers strut A end: eye dims (0.055 u2, 0.036 v, 0.040 w2) centered E+u2*0.012 → spans u2: E-0.0155..E+0.0395; strut A=E+u2*0.034 inside ✓. Plus collar plate at strut A: cyl axis u2 r0.019 depth0.008 at E+u2*0.038 + bolts micro.\n\nLink2 end: fork plates (u2) at W: plates dims (0.045,0.008,0.034) center W-u2*0.006 y±0.022 → span u2 W-0.0285..W+0.0165; strut B = W-u2*0.036 → gap! strut ends before plates start (W-0.036 < W-0.0285). Extend collar: cyl axis u2 r0.015 depth0.05 center W-u2*0.030 spans W-0.055..W-0.005 → covers strut end (W-0.036) ✓ and overlaps plates ✓. r0.015 fits between fork inner faces ±0.018 ✓.\n\nStrut A/B embed distances fine.\n\nBolts on fork plates: 2 small hex per plate + the pin cap.\n\nNow check link1 fork plates vs hub1 collar and pin: pin r0.007 at E spans y±0.05 → ends inside gearbox/motor housings at y ±0.046.. ✓ (gearbox center y0.046 spans 0.037..0.055; pin to ±0.05 ends inside; visible shaft collars on outer faces as designed).\n\nOK. Also elbow thrust washers r0.010 depth0.0025 at y=±0.020? eye v ±0.018, fork inner ±0.025: washers at ±0.021 ✓.\n\nWrist thrust washers r0.008 at y=±0.0175 (block r0.016 v-extent 0.016; fork inner ±0.018) ✓.\n\nNow cove mesh: profile pts (y,z): (-3.0,-0.80), (1.0,-0.80), then curve: center of arc at (1.0, -0.80+0.9)=(1.0,0.10)?? Arc radius 0.9: points for a in 0..90°: y = 1.0 + 0.9*sin(a), z = -0.80 + 0.9*(1-cos(a)): at a=90: y=1.9, z=0.10 → then vertical wall to z=3.2: (1.9, 3.2). Extrude x -3.5..3.5. Build grid: for each x in [-3.5,3.5] two columns; faces quads. Normals face -Y/-Z? Set material both sides (Cycles double-sided default ✓). Add Solidify thickness 0.05 for orbit view? With solidify live modifier fine.\n\nWait floor at z=-0.80 matches desk legs bottom -0.80 ✓.\n\nCove color: (0.62,0.62,0.64) rough 0.6? Slightly darker than desk for separation; lights will brighten.\n\nCamera at (0.98,-1.32,0.60), target (0.20,0.02,0.17). Lens 62. Compute later; fine.\n\nAlso add a soft rectangular \"reflector card\"? skip.\n\nExtra: tiny screws on interface plates — included via micro bolt rings.\n\nMicro bolts on collars: ring 4 r_ring=collar_r*0.72, br=0.0018, bh=0.0025 — tiny; at 1536px with object ~0.5m tall → 0.0018m ≈ 3px — visible barely; make br 0.0025. OK.\n\nAlso \"replaceable interface plates\" at gripper: the tool flange + body front plate (box 0.004 thick at s=0.083 with 4 micro bolts).\n\nName plate on base front: thin box (0.05,0.002,0.014) at (0.0,-0.062,0.030)? On base cylinder surface curved... place on plate front edge instead: (0,-0.086,0.008) small alu plate with fake engraved lines? skip engraving; plain plate ✓.\n\nLEDs: turret front (0,-0.0505,0.075)? turret r0.05 → surface y=-0.05 at x0: LED at (0.0,-0.051,0.075) axis Y green. Elbow motor cap LED amber at (E+(0,-0.086,0)) axis Y. Wrist motor cap LED green (W+(0,-0.056,0)). Controller LED green top. Gripper body LED? maybe on body -v face at s=0.060: point W+u3*0.060+v*(-0.0205) axis -v... body v half 0.020 → face at -0.020 → LED at -0.0215. Amber. ✓ (5 LEDs).\n\nEmission strength 8 small.\n\nCheck no part intersects desk (z<0): base plate z 0..0.014 ✓ all above.\n\nAlso verify link1 strut doesn't hit turret: strut A at A1+u1*0.034 = (0.0253,0,0.1877) region above turret top 0.101 ✓.\n\nCheek plates: from z 0.101 to 0.19: dims z 0.089 center z 0.1455 x dims 0.06 centered x -0.005? Pin at (0,·,0.165) should be within plate: plate x span -0.035..0.025, z 0.101..0.190 ✓. Cheeks bolted to turret top: 4 small bolts each? two per cheek into turret top at (±0.02, ±0.043, 0.101) axis Z? bolts vertical r0.003. Add.\n\nAlso turret top plate bolts 6 ring r0.042 on plate z0.101 top... plate spans z 0.093..0.101, bolts on top face ring 0.042 r0.003 h0.004 ✓.\n\nBase lower cylinder r0.062 z 0.014..0.046; turret r0.05 z 0.058..0.093; ring z 0.046..0.058 dark r0.056; accent ring r0.057 z 0.0565..0.0595? overlap dark ring edge — accent at z 0.057 depth0.002 r0.0565.\n\nUnder-plate rubber pad: dark cylinder r0.075 depth0.002 z0.001? plate square 0.17 — pad circle smaller hidden. skip.\n\nController cable port on base: grommet at (0,-0.058,0.024) r0.006 depth0.006 axis Y dark on lower base cylinder r0.062: surface at y=-0.062 (x=0,z=0.024 vs cyl center z=0.030: offset dz=-0.006 → y_surface = -sqrt(0.062²-0.006²)=-0.0617) place grommet y=-0.060 half-embedded ✓.\n\nAlso add small vertical cable from turret into base? J1 slip ring implied; skip.\n\nEverything set. Also \"recessed cable guides\": add slim channel on link1: thin dark box under strut? The clips suffice. Add 3 clips per link: tiny torus around cable? clips as small boxes bridging cable to beam: at t values, box center p_clip = centerline(t) - w*(depth/2+?) ... cable at offset -w*0.05; clip box from beam surface to cable: center at -w*0.030 dims (0.010 u, 0.016 v, 0.045 w) dark — a slim bracket ✓ oriented frame(u1,v,w1). But strut bottom rail is at -w*h(t); h(t) ~0.02-0.045; clip from rail to cable: position relative bottom rail: rail_z = -h(t); cable at -0.05. Clip center at -(h(t)+0.05)/2 height (h(t)-0.05)... compute per clip: h = h(t)+node radius ~ h(t)+0.009. clip center offset o = (h + 0.05)/2, dims w = 0.05 - h + 0.008. If h>0.05 cable inside section?? h(t) max ~ dA/2*1.15 = 0.046 + radius → ~0.055 > 0.05 at ends! Cable at -0.05 could clip rails near ends. Set cable offset -0.065 to clear (max rail ~0.055+0.011=0.066 hmm at t small h=0.046 radius 0.0147 → surface 0.0607). Cable at -0.068 clears (cable r 0.0022 → 0.0658 vs 0.0607 ✓ barely). Use -0.072 safe. Clips bridge 0.0607..0.072 — clip dims w ~0.02 center -(0.0607+0.072)/2≈-0.066. Compute per-clip in code using h(t)+rad(t) as surface.\n\nLink2: max h = 0.052/2*1.15=0.0299+rad 0.0102 → 0.040. cable offset -0.050, clips accordingly.\n\nCable visible neat under beams ✓ camera sees front (-Y) and below slightly — cables at y=-0.028/-0.024 (front-ish) ✓.\n\nCable endpoints link1: start near turret port at (S + v*(-0.028) - w1*0.02 + u1*0.01, z?) turret top z0.101: start pt (0.008,-0.028,0.108); then clips t=0.25,0.5,0.75 positions along strut underside; end at elbow motor cap (E + v*(-0.084) + w2*0.0?) motor center y -0.0585 cap at -0.083; end point (E.x, -0.083, E.z+0.01). Path AUTO smooth.\n\nPoints count: start, pre-clip (t=0.15), clip1 t=0.30, clip2 t=0.55, clip3 t=0.75, end. Each pt = centerline(t) - w1*0.072 + v*(-0.028).\n\nWait between t=0.85..end cable should curve to motor at y=-0.083: last two pts transition v offset: t=0.9 with v -0.06, then end. ok.\n\nLink2 cable similar from elbow motor top region to wrist motor: start (E+v*(-0.084)+w? start at motor cap top: (E.x, -0.083, E.z+0.012)) hmm same cap both cables attach — fine (two ports). pts along -w2*0.050 + v*(-0.024); end at wrist motor cap (W + v*(-0.056) + w2*0.0) → (W.x, -0.056, W.z).\n\nServo cable as before.\n\nTotal cables: 5. \n\nNow write final code. Also remember: create collections? single fine.\n\nAlso set object names meaningful.\n\nPotential heavy: skin apply ×2 + subsurf — fine.\n\nMembrane grid 8×8 with solidify live + smooth: ok.\n\nEdge case: `primitive_torus_add` signature in 5.x: `major_radius`, `minor_radius`, `abso_major_rad`? In 4.x/5.x it's major_radius/minor_radius with mode 'MAJOR_MINOR' default? The operator uses `major_radius` (outside?) Actually bpy.ops.mesh.primitive_torus_add(align='WORLD', location, rotation, major_segments, minor_segments, mode='MAJOR_MINOR', major_radius=1.0, minor_radius=0.25, abso_major_rad, abso_minor_rad, generate_uvs). With mode MAJOR_MINOR, major_radius = distance center-to-center ✓.\n\nFor axis alignment of torus (default axis Z) use same frame helper.\n\nWrite hex bolt helper:\n```python\ndef bolt(p, axis, r=0.003, h=0.004, mat=steel, washer=True):\n    if washer: cyl(r*1.5, h*0.35, p + axis*h*0.175, axis, verts=24, mat, bevel=0)\n    cyl6 = cyl(r, h, p+axis*(h*0.35+ h/2 ... \n```\nLet me define: washer disc center p + axis*(0.0006), depth 0.0012; head center p + axis*(0.0012 + h/2), depth h. Return.\n\nSimplify: `bolt(p, axis, r, h)`: washer depth 0.3h? Proportions fine.\n\nNow object/orbit robustness: everything 3D from all angles ✓.\n\nSave blend: try/except path: `bpy.ops.wm.save_as_mainfile(filepath='/tmp/robot_arm.blend')`? Unknown writable; use `bpy.path.abspath('//robotic_arm.blend')`. If cwd writable ok. Wrap try/except. Actually harness likely saves itself; but instruction says save complete scene — I'll attempt save to '//blender_bench_scene.blend' in try.\n\nAlso ensure camera set: `scene.camera = cam_obj`.\n\nSet render res 1536, engine cycles, samples 64, denoise.\n\nSet film_transparent False.\n\nTransparent shadows? n/a.\n\nExposure: `scene.view_settings.exposure=0`.\n\nAgX look: try 'AgX - Medium High Contrast' except try 'AgX - Medium High Contrast' variants: in 5.x look enum values might be 'AgX - Medium High Contrast' (same as 4.2). Wrap in try/except, fallback none.\n\nNow compose the code.\n\n```python\nimport bpy, math\nfrom math import sin, cos, pi, radians, atan2, sqrt\nfrom mathutils import Vector, Matrix\n\n# ---------- scene reset ----------\nbpy.ops.object.select_all(action='SELECT')\nbpy.ops.object.delete(use_global=False)\nfor d in (bpy.data.meshes, bpy.data.curves, bpy.data.materials, bpy.data.cameras, bpy.data.lights):\n    pass  # keep default cleanup minimal\n\nscene = bpy.context.scene\nscene.render.engine = 'CYCLES'\nscene.cycles.samples = 64\nscene.cycles.use_denoising = True\nscene.render.resolution_x = 1536\nscene.render.resolution_y = 1536\nscene.render.resolution_percentage = 100\nscene.render.image_settings.file_format = 'PNG'\nscene.unit_settings.system = 'METRIC'\ntry: scene.view_settings.look = 'AgX - Medium High Contrast'\nexcept: pass\n```\n\nMaterials helper:\n\n```python\ndef mat_principled(name, color, metallic=0.0, rough=0.4, transmission=0.0, ior=1.45, emission=None, estr=0.0, coat=0.0):\n    m=bpy.data.materials.new(name); m.use_nodes=True\n    bs=m.node_tree.nodes['Principled BSDF']\n    bs.inputs['Base Color'].default_value=(*color,1)\n    bs.inputs['Metallic'].default_value=metallic\n    bs.inputs['Roughness'].default_value=rough\n    if transmission>0:\n        bs.inputs['Transmission Weight'].default_value=transmission\n        bs.inputs['IOR'].default_value=ior\n    if coat>0: bs.inputs['Coat Weight'].default_value=coat\n    if emission is not None:\n        bs.inputs['Emission Color'].default_value=(*emission,1)\n        bs.inputs['Emission Strength'].default_value=estr\n    return m\n```\n\nMembrane material with noise bump:\n\n```python\nm = mat_principled(...)\nnt=m.node_tree; bs=nt.nodes['Principled BSDF']\nnoise=nt.nodes.new('ShaderNodeTexNoise'); noise.inputs['Scale'].default_value=350; noise.inputs['Detail'].default_value=2.0\nbump=nt.nodes.new('ShaderNodeBump'); bump.inputs['Strength'].default_value=0.12; bump.inputs['Distance'].default_value=0.0003\nnt.links.new(noise.outputs['Fac'], bump.inputs['Height']); nt.links.new(bump.outputs['Normal'], bs.inputs['Normal'])\n```\n\nHelpers: assign_mat(obj,mat); frame basis; cyl; box; torus; bolt; rod; cable; look_at.\n\n```python\ndef frame_from_axis(axis, hint=Vector((0,0,1))):\n    z=Vector(axis).normalized()\n    t = Vector((0,0,1)) if abs(z.z)<0.95 else Vector((1,0,0))\n    x = z.cross(t).normalized()\n    y = z.cross(x).normalized()\n    return x,y,z\n\ndef set_frame(obj, x,y,z, loc):\n    M=Matrix((x,y,z)).transposed().to_4x4(); M.translation=Vector(loc)\n    obj.matrix_world=M\n```\n\ncyl:\n\n```python\ndef cyl(name, r, depth, loc, axis=(0,0,1), mat=None, verts=48, bevel=0.0, smooth=True):\n    bpy.ops.mesh.primitive_cylinder_add(vertices=verts, radius=r, depth=depth, location=loc)\n    o=bpy.context.active_object; o.name=name\n    x,y,z=frame_from_axis(axis)\n    set_frame(o,x,y,z,loc)\n    if mat: o.data.materials.append(mat)\n    if smooth:\n        for p in o.data.polygons: p.use_smooth = len(p.vertices)==4\n    if bevel>0:\n        mod=o.modifiers.new('bev','BEVEL'); mod.width=bevel; mod.segments=3; mod.limit_method='ANGLE'\n    return o\n```\n\nWait: setting matrix_world after creation at location: created with location=loc, rotation identity; then set_frame overrides including translation — fine.\n\nbox:\n\n```python\ndef box(name, dims, loc, frame=None, mat=None, bevel=0.0):\n    bpy.ops.mesh.primitive_cube_add(size=1, location=loc)\n    o=bpy.context.active_object; o.name=name\n    o.dimensions=dims\n    bpy.ops.object.transform_apply(location=False, rotation=False, scale=True)\n    if frame: set_frame(o, *frame, loc)\n    ...\n```\ntransform_apply requires active/selected: after primitive add, it's active ✓.\n\ntorus:\n\n```python\ndef torus(name, R, r, loc, axis=(0,0,1), mat=None):\n    bpy.ops.mesh.primitive_torus_add(major_radius=R, minor_radius=r, major_segments=48, minor_segments=12, location=loc)\n    o=...; set_frame with axis; smooth all polys\n```\n\nbolt:\n\n```python\ndef bolt(name, p, axis, r, h, mat):\n    a=Vector(axis).normalized()\n    cyl(name+'_w', r*1.6, h*0.3, Vector(p)+a*(h*0.15), axis, mat, verts=24, bevel=0)\n    cyl(name+'_h', r, h, Vector(p)+a*(h*0.3+h*0.5), axis, mat, verts=6, bevel=0, smooth=False)\n```\n\nbolt_ring(center, axis, ring_r, n, r, h, mat, phase=0): basis x,y from frame_from_axis(axis): p = center + x*cos*ring_r + y*sin*ring_r.\n\nrod(p1,p2,r,mat,name).\n\ncable(points,r,mat,name).\n\nlook_at(obj, target, track='-Z', up='Y'): use quaternion: \n```python\nd = Vector(target)-obj.location\nobj.rotation_euler = d.to_track_quat('-Z','Y').to_euler()\n```\nFor lights same.\n\nStrut function (returns nodes + frame info):\n\n```python\ndef optimized_strut(name, A, B, dA, dB, rA, rB, bend, n, mat, x_bay=True):\n    A=Vector(A); B=Vector(B); u=(B-A); L=u.length; u.normalize()\n    v=Vector((0,1,0))\n    w=u.cross(v).normalized()\n    v=w.cross(u).normalized()  # ensure orthogonal (v stays ~Y)\n```\nCheck: u×v with v=(0,1,0): for u in XZ plane, u×v = (-u.z,0,u.x) ✓ =w; then v' = w×u: (w.y*u.z-w.z*u.y, w.z*u.x-w.x*u.z, w.x*u.y-w.y*u.x) = (0, w.z*u.x - w.x*u.z? compute: w=(-uz,0,ux): w×u = (0*u.z - u.x*u.y? let me just trust: w×u with both in XZ, v'=(0,?,0): y-comp = w.z*u.x - w.x*u.z = ux*ux - (-uz)(uz)= ux²+uz²=1 → v'=(0,1,0) ✓.\n\n    nodes & edges & radii as planned; returns dict with tops,bots coords, u,v,w, h(t), etc.\n\nSkin build:\n\n```python\n    me=bpy.data.meshes.new(name)\n    me.from_pydata([tuple(p) for p in verts], edges, [])\n    ob=bpy.data.objects.new(name,me)\n    bpy.context.collection.objects.link(ob)\n    sk=ob.modifiers.new('Skin','SKIN')\n    bpy.context.view_layer.update()\n    sv=me.skin_vertices[0].data\n    for i in range(len(sv)): sv[i].radius=(radii[i],radii[i])\n    sv[0].use_root=True\n    bpy.context.view_layer.objects.active=ob\n    ob.select_set(True)\n    bpy.ops.object.modifier_apply(modifier='Skin')\n    for p in me.polygons: p.use_smooth=True\n    sub=ob.modifiers.new('Sub','SUBSURF'); sub.levels=2; sub.render_levels=2\n    ob.data.materials.append(mat)\n```\n\nmodifier_apply on non-selected? ensure selected: after link, select only it: `bpy.ops.object.select_all(action='DESELECT')` then select. ok.\n\nMembrane panel:\n\n```python\ndef membrane(name, c00,c10,c11,c01, normal, mat, bow=0.0028, nx=8, ny=8, inset=0.10):\n    C=(c00+c10+c11+c01)/4\n    def ins(p): return p+(C-p)*inset\n    P=[ins(c00),ins(c10),ins(c11),ins(c01)]\n    verts=[]; faces=[]\n    for j in range(ny+1):\n        s=j/ny\n        for i in range(nx+1):\n            r=i/nx\n            p=(1-r)*(1-s)*P[0]+ r*(1-s)*P[1]+ r*s*P[2]+ (1-r)*s*P[3]\n            p=p+Vector(normal)*(bow*sin(pi*r)*sin(pi*s))\n            verts.append(tuple(p))\n    for j in range(ny):\n        for i in range(nx):\n            a=j*(nx+1)+i; faces.append((a,a+1,a+nx+2,a+nx+1))\n    me=...from_pydata(verts,[],faces)\n    ob=...; \n    for p in me.polygons: p.use_smooth=True\n    sol=ob.modifiers.new('Solid','SOLIDIFY'); sol.thickness=0.0011; sol.offset=0\n    ob.data.materials.append(mat)\n```\n\nInset 0.10 relative each corner → gap ~10% of bay size (~0.02*0.1=2mm?) bay ~20mm long, 30mm tall → inset ~2-3mm from rails: with rail radius ~9mm, film edge well under rails?? inset moves corner toward centroid by 10% of diagonal — gap between film edge and rails ~ small; rails cover seam from camera? Not exactly but fine visually (film slightly inside frame). Use inset 0.06.\n\nThen main assembly code — long but straightforward. Let me write positions concretely.\n\nBase:\n```\nplate: box dims (0.17,0.17,0.014) loc (0,0,0.007) bevel 0.008, dark\n4 bolts at (±0.072,±0.072,0.014) axis +Z r0.0045 h0.005\nbase_lower: cyl r0.062 d0.032 loc(0,0,0.030) alu bevel0.004\nring_dark: cyl r0.056 d0.012 loc(0,0,0.052) darksteel? use mat_dark\nring_accent: cyl r0.0568 d0.0022 loc(0,0,0.057) accent\nturret: cyl r0.050 d0.036 loc(0,0,0.076) alu bevel0.004\ntopplate: cyl r0.055 d0.008 loc(0,0,0.098) dark bevel0.002\ntopplate bolts ring r0.043 n6 r0.0028 h0.0035 at z0.102 axis Z\nturret LED at (0,-0.0508,0.076) axis -Y? LED cyl axis Y at (0,-0.0505,0.076): bezel dark r0.0035 d0.002, led r0.0022 d0.001 emissive — position slightly proud: bezel center (0,-0.0498,0.076) depth 0.002 axis Y → spans -0.0508..-0.0488 half in turret. ok.\ncheeks: boxes dims (0.060,0.014,0.089) loc (-0.005,±0.043,0.1455) bevel0.006 alu\ncheek bolts: 2 per cheek into top plate: at (-0.02/0.012, ±0.043, 0.103) axis Z r0.0025 h0.003\ngearbox(+Y): cyl r0.032 d0.026 loc(0,0.063,0.165) axis Y dark? make alu with dark cap:\n  gb housing alu bevel0.004; gb cap r0.020 d0.008 loc(0,0.080,0.165) dark; collar r0.013 d0.006 loc(0,0.086,0.165) steel; center hex bolt r0.0045 h0.004 at (0,0.089,0.165) axis Y.\n  gb bolts ring r0.024 n4 r0.0022 on face y=0.0775 axis +Y? place ring on cap front y0.0845.\nmotor(-Y): flange cyl r0.028 d0.005 loc(0,-0.053,0.165) dark; housing r0.024 d0.048 loc(0,-0.079,0.165) alu bevel0.004; cap r0.0245 d0.006 loc(0,-0.106,0.165) dark; collar r0.011 d0.005 loc(0,-0.110,0.165) steel + hex r0.004.\npin visual: shaft collars done; actual pin cyl r0.0105 d0.17 loc(0,0,0.165) axis Y steel (hidden mostly, ends into collars).\nthrust washers: cyl r0.0135 d0.003 loc(0,±0.0305,0.165) axis Y steel.\nstop tabs: boxes dims(0.014,0.010,0.018) loc(-0.032,±0.030,0.148) dark bevel0.002\nnameplate: box dims(0.055,0.002,0.016) loc(0,-0.0862,0.007)?? plate front edge at y=-0.085; plate z center 0.007 → nameplate on front face: loc(0,-0.0855,0.007) dims(0.05,0.002,0.010) alu. ok.\n```\n\nLink1 root hub: cyl r0.026 d0.062 axis u1 loc A1+u1*0.008 bevel0.004 alu; collar plate at strut side: cyl r0.029 d0.005 axis u1 loc A1+u1*0.040 dark; micro bolts ring on collar face at A1+u1*0.0435 axis u1 ring r0.022 n4 r0.002 h0.003.\n\nStrut1: A=A1+u1*0.036 → hub spans to A1+0.039: strut A inside collar ✓ (A at 0.036 within collar 0.0375..0.0425? collar center 0.040 depth0.005 spans 0.0375..0.0425; strut start node at 0.036 slightly before collar → inside hub (ends 0.039) ✓.\nB=E-u1*0.040. Link1 end collar: cyl r0.020 d0.05 axis u1 loc E-u1*0.028 spans E-0.053..E-0.003 → covers B(0.040→ E-0.040 inside ✓). r0.020 between fork inner faces ±0.025 ✓. micro bolts ring at E-u1*0.048 face? collar face at E-0.053: ring there axis -u1 r0.014 n4.\nFork plates link1-end: boxes dims(0.052,0.010,0.046) frame(u1,v,w1) loc E-u1*0.008 + v*±0.030, bevel0.005. Plate spans u: E-0.034..E+0.018.\nFork plate bolts: 2 per plate at E-u1*0.020/E+u? on outer faces axis v... skip (pin caps exist).\nPin: cyl r0.007 d0.10 axis Y loc E steel; thrust washers r0.0105 d0.0025 at y=±0.0215 axis Y loc (E.x,±0.0215,E.z).\nGearbox(+Y): r0.022 d0.018 loc(E.x,0.046,E.z); cap r0.014 d0.006 y0.058; collar r0.009 y0.0625 steel; hex r0.0035.\nMotor(-Y): flange r0.021 d0.004 y-0.037; housing r0.019 d0.044 y-0.060; cap r0.0195 d0.005 y-0.0845; collar r0.009 y-0.088; LED amber at (E.x,-0.0875,E.z+0.008)? place on cap face: bezel r0.003 at y-0.0878 z E.z; led.\nHmm motor housing from -0.038..-0.082 ✓ overlaps fork outer (0.035) ✓ flange between.\n\nLink2 root eye: box dims(0.056,0.036,0.040) frame(u2,v,w2) loc E+u2*0.012 bevel0.012 alu. Spans u2: E-0.016..E+0.040.\nRoot collar at strut side: cyl r0.0195 d0.006 axis u2 loc E+u2*0.041 dark + micro bolts ring r0.014 n4 at face E+u2*0.0445 axis u2.\nStrut2: A2=E+u2*0.038 (inside collar/eye ✓ eye ends 0.040, collar 0.038..0.044) → strut start node at 0.038 embedded ✓. B2=W-u2*0.034.\nLink2 end collar: cyl r0.015 d0.05 axis u2 loc W-u2*0.028 spans W-0.053..W-0.003 ✓ covers B2.\nFork plates link2-end: dims(0.046,0.008,0.034) frame(u2,v,w2) loc W-u2*0.006+v*±0.022 bevel0.004. spans u: W-0.029..W+0.017. inner faces y±0.018 ✓ collar r0.015 fits.\nPin: r0.005 d0.072 axis Y loc W. thrust washers r0.0085 d0.002 y±0.017.\nEncoder(+Y): housing r0.0135 d0.012 loc(W.x,0.024,W.z) alu; cap r0.010 d0.005 y0.0325 dark; collar r0.006 y0.036 steel hex.\nMotor(-Y): flange r0.014 d0.004 y-0.020; housing r0.0125 d0.030 y-0.037; cap r0.013 d0.005 y-0.0545; LED green y-0.0575.\nWrist block: cyl r0.016 d0.034 axis Y loc W alu bevel0.003 (rotating part between forks: v ±0.017 vs inner ±0.018 ✓).\n\nRoll actuator: base collar r0.0165 d0.004 axis u3 at W+u3*0.002 dark? Actually block r0.016 axis Y; actuator must attach to block face oriented u3 — the block is cylinder along Y; its surface around... The actuator cylinder r0.0145 d0.034 axis u3 loc W+u3*0.019 partially embedded in block (r0.016) ✓ intersection fine (assembled).\nAccent ring: torus R0.0148 r0.0016 axis u3 at W+u3*0.037.\nFlange: cyl r0.019 d0.006 axis u3 loc W+u3*0.041 dark? steel? make alu dark: dark. bolts ring r0.014 n4 r0.002 h0.0028 at face W+u3*0.0445 axis u3 steel.\nBody: box dims(0.036,0.040,0.024) frame(u3,v,w3) loc W+u3*0.065 bevel0.005 dark. spans s0.047..0.083.\nFront plate: box dims(0.004,0.036,0.020) loc W+u3*0.0845 bevel0.001 alu + 4 micro bolts r0.0016 at corners? place ring n4 r0.011 axis u3 face s0.0868.\nServo: cyl r0.0085 d0.020 axis w3 loc W+u3*0.058+w3*0.020 alu; cap r0.0088 d0.004 dark at w3*0.031; servo flange r0.010 d0.003 at w3*0.011 dark.\nBody top recess? skip.\nRails: at s=0.092: rods axis v r0.0028 d0.044 loc W+u3*0.092 ± w3*0.0065 steel.\nHmm front plate spans v ±0.018; rods to ±0.022 held by end plates at y±0.0225: end plates box dims(0.020,0.004,0.018) frame loc W+u3*0.092+v*±0.0225 bevel0.002 alu.\nWait rods at s=0.092 beyond front plate (0.083..0.0865)... rods floating held only by end plates which attach to?? End plates need connection to body: extend end plates backward: dims u 0.026 → from s0.079..0.105 overlapping body front (to 0.083) ✓ attach visually + micro bolt each. Carriages at s=0.095 y±0.017 dims(0.014,0.009,0.016) bevel0.002 steel-dark? machined alu.\nCarriage spans u 0.088..0.102 ✓ around rods (0.092) ✓. Rods thread carriage v-range 0.0125..0.0215? carriage y center 0.017 half 0.0045 → 0.0125..0.0215; rods at w3 ±0.0065 within carriage w3 half 0.008 ✓.\nPivot pins: cyl r0.0032 d0.012 axis v loc W+u3*0.092+v*±0.017 steel + cap discs r0.0048 d0.0015 at v±0.0232.\nFinger plates: dims(0.046,0.0045,0.012) loc W+u3*0.107+v*±0.017 bevel0.0015 alu. spans s0.084..0.130.\nPads: dims(0.012,0.0030,0.010) loc W+u3*0.124+v*±0.01525 pad mat bevel0.001. inner faces ±0.01375 → gap 0.0275. object head r0.013 dia 0.026 ✓.\nPad bolts: 2 micro per pad outer face? skip.\nLinkage rods: P1=W+u3*0.058+w3*0.028 (servo nose area → servo spans w3 0.010..0.030: nose at 0.030; P1 at 0.028 inside? set P1 = W+u3*0.058+w3*0.0305) to P2=W+u3*0.100+v*±0.017+w3*0.0075. r0.0016 steel. plus tiny clevis cylinders at ends r0.0025 d0.003? skip.\nBody LED amber: at W+u3*0.060+v*(-0.0206) axis -v: bezel+led.\nGripper cable: points: W+v*(-0.014)+w3*0.010? start at wrist motor? start at wrist block: (W+v*(-0.017)+w2*0.005) → mid W+u3*0.030+v*(-0.020)+w3*0.006 → end servo W+u3*0.058+w3*0.020+v*(-0.006)? servo at w3 0.020 center; cable enters servo side: end W+u3*0.058+w3*0.020+v*(-0.009). r0.0016.\n\nObject placement: F=W+u3*0.130 → obj_x=F.x+u3.x*0.018.\n\nCompute numeric sanity: u2: Δ=(0.425-0.2229, 0.165-0.3657)=(0.2021,-0.2007) L2=0.2848 u2=(0.7097,-0.7045)?? u2=(0.7097,0,-0.7045). θ2=atan2(-0.7045,0.7097)=-44.77°. θ3=-72.77°: u3=(cos,0,sin)=(0.2957,0,-0.9553).\nW=(0.425,0,0.165). F=(0.425+0.0384,0,0.165-0.1242)=(0.4634,0,0.0408). obj_x=0.4634+0.0053=0.4687 ✓. Pads z: 0.165-0.1185=0.0465 ±0.005 → bottom 0.0415 vs obj top 0.036 gap 5.5mm ✓.\n\nElbow E=(0.2229,0,0.3657) ✓.\n\nStrut1: A=A1+u1*0.036=(0.0268,0,0.1891); B=E-u1*0.040=(0.1932,0,0.3389). \nStrut2: A2=E+u2*0.038=(0.2499,0,0.3389)?? E+u2*0.038=(0.2229+0.0270,0,0.3657-0.0268)=(0.2499,0,0.3389). B2=W-u2*0.034=(0.425-0.0241,0,0.165+0.0239)=(0.4009,0,0.1889).\n\nMembrane bays: strut1 n=12 bays idx 3 and 8; strut2 n=11 bay 5 (also X at mid bay 5? x_bay mid = n//2: strut2 mid=5 → X there; choose membrane bay 4 and 7? pick bay 4). Strut1 X at bay 6.\n\nCables: \nc1 base internal: [(0.0,-0.112,0.150)?? motor rear cap at y-0.106..-0.109 z0.165: start (0,-0.109,0.158), ( -0.005,-0.095,0.125), (-0.015,-0.06,0.106), (-0.022,-0.035,0.103)] port grommet at (-0.022,-0.033,0.102) r0.005 dark axis Z? turret top at z0.094..? turret spans 0.058..0.094; topplate 0.094..0.102. Port on topplate edge... place grommet cyl r0.005 d0.006 at (-0.022,-0.033,0.100) axis Z dark ✓ cable end there.\n\nc2 link1: pts: start (0.010,-0.026,0.106)?? another grommet at (0.012,-0.026,0.100). Then t=0.12: centerline S+u1*(0.30*0.12)=S+u1*0.036=(0.0267,0,0.1891) offset -w1*0.072 → w1=(-0.669,0,0.743): -w1*0.072=(0.0482,0,-0.0535) → pt (0.0749,-0.026,0.1356). Hmm at t=0.12 the strut is near hub r0.026... cable at 0.072 below centerline — clear of hub (0.026) ✓.\n t=0.30: cl=(0.0669,0,0.2254) → +(0.0482,0,-0.0535)=(0.1151,-0.026,0.1719)\n t=0.55: cl=(0.1226,0,0.2755) → (0.1708,-0.026,0.2220)\n t=0.78: cl=(0.1738,0,0.3216) → (0.2220,-0.026,0.2681)\n end: elbow motor cap top: (E.x,-0.086, E.z+0.005) = (0.2229,-0.086,0.3707)\nTransition from v-0.026 to -0.086 at end — AUTO handles smooth S. Maybe add pt t=0.90 v-0.05: cl=(0.2008,0,0.3458)-w1*0.072=(0.249,-0.05,0.292)+ ... fine.\n\ncable radius 0.0022 mat_cable.\n\nclips at t=0.30,0.55,0.78: surface offset h(t)+rad(t): compute in code; clip box dims (0.012,0.018, surface+0.072+0.004)?? clip from strut surface to cable: center offset -( (h+r) + 0.072 )/2 along w1; dims w = 0.072-(h+r)+0.006. Compute h(t), rad(t) via same formulas — replicate in clip loop using strut dict (store function closures). I'll have strut return dict with 'h' and 'rad' lambdas and frame.\n\nc3 link2: start elbow motor cap (0.2229,-0.086,0.3707)? same cap two cables ok → start (0.2259,-0.086,0.3727) slight offset. pts along strut2 -w2*0.050 v-0.024: w2=(0.7045,0,0.7097): -w2*0.05=(-0.0352,0,-0.0355).\n t=0.15: cl=E+u2*(L2*0.15)=E+u2*0.0427=(0.2532,0,0.3356) → (0.2180,-0.024,0.3001)\n t=0.40: cl=(0.3036,0,0.2855)→(0.2684,-0.024,0.2500)\n t=0.65: cl=(0.3541,0,0.2354)→(0.3189,-0.024,0.1999)\n t=0.88: cl=(0.3989? compute E+u2*0.2506=(0.4008,0,0.1892))→(0.3656,-0.024,0.1537)\n end wrist motor cap: (W.x,-0.056,W.z+0.004)=(0.425,-0.056,0.169)\nclips similar with strut2.\n\nc4 servo cable (above).\nc5 controller cable.\nc1? included.\n\nController box: loc(-0.20,-0.13,0.016) dims(0.10,0.070,0.032) bevel0.006 dark; lid plate dims(0.09,0.06,0.003) loc z0.0335 alu dark? top plate steel-ish dark; LED green at (-0.175,-0.145,0.035) axis Z; port grommet front (facing base): at (-0.155,-0.105,0.014) r0.0045 axis? direction toward base: yaw... place on box face +x side: face at x=-0.15: grommet cyl r0.0045 d0.005 axis X at (-0.149,-0.115,0.014)? box x span -0.25..-0.15 ✓ y -0.165..-0.095: y=-0.115 ✓.\nCable pts: [(-0.146,-0.115,0.014),(-0.10,-0.105,0.005),(-0.05,-0.085,0.004),(-0.015,-0.070,0.005),(0.0,-0.062,0.016)] end at base grommet (0,-0.060,0.020) r0.005 axis Y at (0,-0.0595,0.022)?? base_lower r0.062 center z0.030: at z0.022 dy = sqrt(0.062²-0.008²)=0.0615 → grommet at (0,-0.0605,0.022) axis Y ✓.\n\nSmall parts: bearing at (0.395,0.115): outer torus R0.0085 r0.0032 steel at z0.0032 axis Z; inner torus R0.0085? classic bearing: outer ring torus, inner ring torus R same? Use: outer cyl ring: torus R=0.0072 minor 0.0028; balls: 6 spheres r0.0022 at R0.0072 z0.0028; inner torus R0.0072? For simplicity: two tori (R0.0095 minor0.0025 outer; R0.0055 minor0.0022 inner) + 6 balls R0.0075 r0.0021. All at z≈0.0025-0.003. \nWasher: torus R0.0045 minor0.0016 at (0.435,0.075,0.0016).\n\nAlso maybe a small hex driver tool? skip.\n\nObject (target): name \"TargetPart\":\npuck cyl r0.020 d0.006 z0.003 alu bevel0.0015\nring groove accent: torus R0.0175 r0.0012 at z0.006 orange\nneck cyl r0.0115 d0.014 z0.013 alu\nhead cyl r0.013 d0.016 z0.028 alu bevel0.004\nhead torus accent R0.0128 r0.0014 z0.024\nhex socket dark cyl r0.004 d0.002 z0.0365 verts6 (half-embedded in head top z0.036: spans 0.0355..0.0375 proud 0.0005 — reads as insert? make depth 0.0015 at z0.0362 → top 0.0369 slight proud acceptable as socket cap. Or darker disc flush. fine.\n\nDesk: box dims(1.6,0.95,0.045) loc(0.18,0.02,-0.0225) bevel0.012 mat_desk. spans x -0.62..0.98, y -0.455..0.495. base at origin ✓ controller (-0.2,-0.13) ✓ object 0.469 ✓ bearing (0.395,0.115) ✓.\nLegs: panels dims(0.05,0.85,0.755) loc(-0.48,0.02,-0.4225) and (0.84,0.02,-0.4225) bevel0.008 mat dark? legs matte light gray alu? Use dark alu for contrast. Floor z=-0.80: legs from -0.045..-0.80 ✓.\nFloor/cove mesh as planned, mat_floor.\nAlso desk rear edge cable? no.\n\nCheck camera sees desk front edge: desk y front -0.455; camera y -1.32 → sees edge + floor below ✓ nice depth.\n\nCove: mat_floor same.\n\nNow lights + camera + world.\n\nCamera loc (0.98,-1.32,0.60) — check frame width at target dist 1.6: 0.99m. Scene x range -0.25(controller)..0.55(gripper+object 0.49) → 0.8 ✓. Vertical: elbow top 0.39 + gearbox? E.z+ r ~0.39; desk front bottom edge... fits.\n\nActually consider lens 65 → frame 0.885 wide; content 0.8 → tight-ish margins; use 60mm → 0.96. Keep 60.\n\nDOF focus at (0.36,0,0.14) fstop 7.\n\nLight energies with AgX: key 800W area size 0.9 at (0.5,-1.0,1.6); rim 650 at (0.7,1.1,1.4) size 0.6; fill 280 at (-1.1,-0.6,0.7) size 0.8 color cool; top 450 at (0.1,0.3,2.3) size 1.0. World strength 0.35.\n\nShould be well-lit.\n\nNow, potential issue: `bpy.ops.object.transform_apply` in box() changes context; ensure object active: after primitive_cube_add it is. ✓\n\nFor `cyl` smooth: caps are single n-gons (end_fill_type='NGON' default) ✓ len>4.\n\nBevel modifier on cylinders with smooth sides: bevel faces inherit smooth? Result typically fine.\n\nModifiers count high but ok.\n\nGLB export will apply modifiers — skin already applied; subsurf applied by exporter (it applies). Solidify applied ✓. Bevels applied ✓. Curves → exporter converts? glTF exporter exports curves as meshes (it converts bevelled curves? I believe exporter handles curves by converting to mesh). The benchmark handles it; fine.\n\nAlso set viewport display colors? not needed.\n\nAdd empty for camera target & DOF.\n\nNames via helper counters to keep unique (bpy auto-uniquifies anyway).\n\nAlso, \"visible rotating platform\" — turret + top plate with bolts reads as such; accent seam ring emphasizes rotation joint ✓. Maybe add rotation index marks: tiny notch box on turret side + tick on ring: add small dark box (0.004,0.002,0.010) at turret front (0,-0.0495,0.076)? that's where LED... put index mark at (0.03,-0.04,0.076)? skip, LED enough.\n\nNow write the membrane normal: ±v — choose +v (back) or -v? irrelevant; use v*1.\n\nFor strut1: membrane bays [3,8]; strut2 bay [4].\n\nPanel corners: tops[i], tops[i+1], bots[i+1], bots[i].\n\nAlso X-bay: middle bay gets both diagonals.\n\nEdge list build carefully with vertex indices: verts order: for i: top then bottom appended → top_i=2i, bot_i=2i+1.\n\nEdges: rails (2i,2i+2),(2i+1,2i+3); ends (0,1),(2n,2n+1); diagonals per parity; X extra.\n\nRadii list per vertex.\n\nbend: strut1 bend=-0.012 (toward -w1 → down-forward bow ✓); strut2 bend=-0.010.\n\nAlso depth profile prof uses |cos(pi t)|**0.75: at t=0: 1.15; t=0.5: 0.6. Wait 0.6+0.55*0=0.6 min ✓.\n\nh(t) = (dA+(dB-dA)t)/2 * prof(t).\n\nrad(t) = (rA+(rB-rA)t)*(1.30-0.5*sin(pi t)).\n\nStrut1: rA 0.0115→ ends 0.01495, mid 0.008*0.8? mid t0.5: base ~0.01*(0.8)=0.008. Depth ends: 0.080/2*1.15=0.046; mid 0.068/2*0.6=0.0204. Beam span 0.226: slender organic ✓.\n\nCheck strut1 doesn't intersect cheeks: near t=0 strut at A1+0.036 +... cheeks at y±0.036 inner; strut in v=0 plane ✓ no.\n\nStrut1 bottom rail near t=0 at -w1*0.046 → point A + (-w1)*0.046: A=(0.0268,0,0.1891) + (0.0308,0,-0.0342)=(0.0576,0,0.1549). Clear of turret (r0.05, top 0.102) ✓ clear of cheeks (y±0.036..0.050) ✓ v=0 plane ✓.\n\nOK.\n\nSkin root vertex: mark vertex 0.\n\nSubsurf render_levels 2.\n\nOne more: materials for strut: titanium with subtle anisotropic? Principled 'Anisotropic IOR Level'? input name 'Anisotropic IOR Level' in 4.x+. Set 0.3? risky name; use bs.inputs.get('Anisotropic IOR Level'). skip.\n\nFinal scene stats fine.\n\nAlso add bevel to membrane? no.\n\nAdd bevel to finger plates etc via box bevel param ✓.\n\nLet me also consider making link1 slightly darker tint vs link2? Both titanium same ✓.\n\nAccent rings also at wrist roll and base — consistent design language ✓.\n\nWrite the code now. Also include a ground-contact shadow? Cycles handles.\n\nAlso maybe set `scene.render.film_transparent=False` default ✓.\n\nSave file at end try/except.\n\nAlso, ensure `bpy.context.collection` valid — use scene.collection children: use `bpy.context.scene.collection.objects.link(ob)`? Use a dedicated collection: `col=bpy.data.collections.new('RobotArm'); scene.collection.children.link(col)` and link objects to col. For ops-created primitives they go to context collection (default Collection). Mixed fine. For non-ops (strut, membrane, cable), link to scene collection: `bpy.context.scene.collection.objects.link(ob)`? scene.collection is master; objects.link works on Collection. Yes.\n\nLet me finalize cable helper:\n\n```python\ndef cable(name, pts, r, mat):\n    cu=bpy.data.curves.new(name,'CURVE'); cu.dimensions='3D'\n    cu.resolution_u=12; cu.bevel_depth=r; cu.bevel_resolution=3; cu.resolution_u=16\n    sp=cu.splines.new('BEZIER'); sp.bezier_points.add(len(pts)-1)\n    for bp,co in zip(sp.bezier_points,pts):\n        bp.co=co; bp.handle_left_type='AUTO'; bp.handle_right_type='AUTO'\n    ob=bpy.data.objects.new(name,cu); bpy.context.scene.collection.objects.link(ob)\n    ob.data.materials.append(mat)\n    return ob\n```\n\nLook-at helper.\n\nLight helper:\n\n```python\ndef area_light(name, loc, energy, size, target, color=(1,1,1), shape='DISK'):\n    ld=bpy.data.lights.new(name,'AREA'); ld.energy=energy; ld.color=color; ld.shape=shape; ld.size=size\n    ob=bpy.data.objects.new(name,ld); scene.collection.objects.link(ob); ob.location=loc\n    look_at(ob,target)\n    return ob\n```\n\nWorld:\n\n```python\nw=bpy.data.worlds.new('Studio'); scene.world=w; w.use_nodes=True\nbg=w.node_tree.nodes['Background']; bg.inputs['Color'].default_value=(0.62,0.63,0.67,1); bg.inputs['Strength'].default_value=0.35\n```\n\nCamera:\n\n```python\ncd=bpy.data.cameras.new('Cam'); cd.lens=60; cd.sensor_width=36\ncam=bpy.data.objects.new('Camera',cd); scene.collection.objects.link(cam)\ncam.location=(0.98,-1.32,0.60); look_at(cam,(0.20,0.02,0.17))\ncd.dof.use_dof=True; cd.dof.aperture_fstop=7.0\nfocus=empty at (0.37,0,0.15); cd.dof.focus_object=focus\nscene.camera=cam\n```\n\nEmpty: `bpy.data.objects.new('Focus',None)`.\n\nAlso slight camera roll? no.\n\nNow, is 0.6m frame height enough at target for full arm? Arm top 0.39 vs target z0.17: +0.22; frame half-height 0.48 ✓. Desk front bottom edge: point (0.18,-0.455,-0.045): relative to cam... it'll be in lower frame ✓.\n\nOne more check — the benchmark renders orbit around scene; floor cove covers y to -3? cove floor part from y=-3.0 to 1.0 then curves up. Camera orbit radius maybe ~1.5-2 → stays on floor ✓. Cove width x ±3.5 ✓.\n\nCove mesh:\n\n```python\nprof=[(-3.0,-0.80),(1.0,-0.80)]\nimport math\nfor k in range(1,10):\n    a=pi/2*k/9\n    prof.append((1.0+0.9*sin(a), -0.80+0.9*(1-cos(a))))\nprof.append((1.9,3.0))\nxs=[-3.5,3.5]\nverts=[(x,y,z) for y,z in prof for x in xs]  # careful ordering\nfaces: for i in range(len(prof)-1): quad (i*2, i*2+1, i*2+3, i*2+2)\n```\nNormal orientation: facing -y/-z toward camera region. Double-sided render default in Cycles ✓.\n\nSolidify modifier thickness 0.05 offset 0.\n\nDesk legs also visible in orbit ✓.\n\nAlright, also add slight bevel to desk via bevel modifier ✓.\n\nPotential z-fighting: grommets half-embedded fine.\n\nTime to also double check `primitive_cylinder_add` param name `vertices` ✓, `radius`,`depth` ✓.\n\n`primitive_torus_add`: parameters major_radius/minor_radius exist with mode default 'MAJOR_MINOR'? In Blender 4.x+, operator params: mode ('MAJOR_MINOR'), abso_major_rad, abso_minor_rad, major_radius, minor_radius... I recall major_radius & minor_radius work with mode MAJOR_MINOR (relative) — yes standard usage `bpy.ops.mesh.primitive_torus_add(major_radius=R, minor_radius=r)` common. ✓\n\nSkin: after `me.from_pydata`, adding SKIN modifier — need `bpy.context.view_layer.update()` before accessing skin_vertices? Common script pattern:\n\n```python\nmod = obj.modifiers.new('','SKIN')\nme.skin_vertices[0].data[0].radius = ...\n```\nworks without update generally. I'll include update anyway.\n\nmodifier_apply: ensure object selected & active:\n```python\nbpy.ops.object.select_all(action='DESELECT')\nob.select_set(True); bpy.context.view_layer.objects.active=ob\nbpy.ops.object.modifier_apply(modifier=mod.name)\n```\n\nThen shade smooth & subsurf.\n\nI think we're ready. Also add \"Subsurf\" only render? viewport levels 2 ok.\n\nMembrane material side: transmission with thickness — set `m.surface_render_method`? In 4.2+, for alpha blend there's surface_render_method ('DITHERED'/'BLENDED')? Not needed for transmission.\n\nIOR 1.38, transmission 0.9, roughness 0.35, base color (0.72,0.78,0.82), metallic 0, coat 0.25.\n\nPads mat: (0.85,0.38,0.06) rough 0.55 metallic 0.0.\n\nAccent mat: (0.80,0.25,0.04) metallic 0.85 rough 0.3.\n\nCheck LED emissive visible at 64 samples small size — yes bright points.\n\nAlso I want a subtle bevel on every cyl: default bevel=0.0015 for >0.01 r. I'll pass per-call.\n\nNow assemble full code. Also include comments. Ensure no syntax errors, no undefined vars. Let me write it mentally clean.\n\nAlso caution: `Matrix((x,y,z)).transposed()` — Matrix rows from vectors; transposed gives columns = x,y,z ✓.\n\nlook_at:\n\n```python\ndef look_at(ob, target):\n    d=Vector(target)-ob.location\n    ob.rotation_euler=d.to_track_quat('-Z','Y').to_euler()\n```\n\nFor cylinders I use set_frame which sets matrix_world — overrides rotation entirely ✓.\n\nFor boxes with frame param: pass (x,y,z) tuple.\n\nWrite micro helpers for repeated joint builds to reduce code? I'll write inline but concise.\n\nAlso add `import bpy` etc.\n\nEdge: `bpy.ops.object.transform_apply` poll needs object mode ✓ headless default.\n\nNumber formatting fine.\n\nLet me also double check fork plates frame: box with frame (u1,v,w1) where v=Y — dims map (x→u1 dim0.052, y→v 0.010, z→w1 0.046) ✓.\n\nCheek plates: plain axis-aligned boxes (frame None).\n\nOne risk: too many modifiers (bevels) slow GLB export — acceptable.\n\nAlso set each object's `data.materials` before modifiers fine.\n\nFinally set scene frame? not needed.\n\nAlso name the file save: \n\n```python\ntry:\n    bpy.ops.wm.save_as_mainfile(filepath=bpy.path.abspath('//robot_arm_studio.blend'))\nexcept Exception as e:\n    print('save failed', e)\n```\n\nPrint done.\n\nLet me also add a few tick marks / rotation indicator: small orange box on turret: (0.0,-0.0492,0.082) dims (0.006,0.0015,0.008)? LED at z0.076 y-0.0505... LED bezel dark r0.0035 at (0,-0.0495,0.072), led core r0.0022 at y-0.0508. Add orange tick at (0,-0.0498,0.085) dims(0.005,0.0012,0.006) accent ✓ rotation index.\n\nAlso add a couple of small screw heads on cheek outer faces near bottom: 2 bolts per cheek axis ±Y at (±? cheeks y outer ±0.050: bolt at (-0.02, ±0.0505, 0.12) axis Y r0.0028. Add.\n\nOK writing final code. I'll be careful with the strut dict return:\n\n```python\ndef optimized_strut(name,A,B,dA,dB,rA,rB,bend,n,mat,xbrace=True):\n    ...\n    return {'obj':ob,'tops':topsP,'bots':botsP,'u':u,'v':v,'w':w,'A':A,'B':B,'L':L,'h':hfun,'rad':rfun}\n```\ntopsP/botsP lists of Vector positions.\n\nClips:\n\n```python\ndef cable_clip(name, strut, t, cable_off, mat):\n    u=strut['u']; v=strut['v']; w=strut['w']; A=strut['A']; L=strut['L']\n    cl=A+u*(L*t)+ w*(0)  # centerline without bend? include bend: strut center C included bend; recompute:\n```\nStore bend in dict; center(t)=A+u*(L t)+w*(bend sin(pi t)). surface = h(t)+rad(t). clip spans from surface-0.004 to cable_off+0.004: depth=(cable_off - surface)+0.010; center offset = surface + depth/2 - 0.004?? Let me: inner end at surface-0.003 (embedded slightly into beam region... beam surface at `surface` from centerline; clip from surface-0.002 to cable_off+0.002: depth = cable_off+0.002-(surface-0.002) = cable_off-surface+0.004; center off = (surface-0.002 + cable_off+0.002)/2 = (surface+cable_off)/2.\ndims: (0.012 along u, 0.020 along v, depth along w). loc = center(t) - w*center_off (cable on -w side). frame (u,v,w). mat dark.\n\nCable offsets: link1 cable_off=0.072; link2 0.050.\n\nCable point function: pt(t, voff) = center(t) - w*cable_off + v*voff.\n\nGood. Now strut2 L = (B2-A2).length etc — all within function.\n\nAlso membrane from strut dict: bays indexes within n.\n\nWrite everything. Also second small membrane on strut1 bay 8 normal -v? same.\n\nAlso I realize pin at shoulder `cyl r0.0105 d0.17` spans y ±0.085 — ends near collars ✓.\n\nAlso shoulder motor flange at y=-0.053 overlaps cheek outer (0.050) ✓.\n\nGearbox y0.063 spans 0.050..0.076 ✓ from cheek outer face.\n\nElbow gearbox at y 0.046 spans 0.037..0.055; fork outer 0.035 — small gap 0.002: fine add flange r0.024 d0.004 at y0.036.\n\nEncoder cap wrist y0.024 spans 0.018..0.030: fork outer 0.026 → overlaps fork plate (0.018..0.026)?? fork plate y center ±0.022 dim 0.008 → spans 0.018..0.026. Encoder 0.018..0.030 intersects fork plate region at W — but encoder is AT W (axis center) where pin/block are; fork plate is around W too (plate spans u W-0.029..W+0.017 at y 0.018..0.026). Encoder cylinder r0.0135 at y0.018..0.030 → overlaps fork plate y0.018..0.026 region. Physically encoder mounts ON fork outer face (0.026): shift encoder to y center 0.032 spans 0.026..0.038 ✓, cap y0.0405, collar y0.044. Motor wrist: flange at y-0.027, housing y-0.043 spans -0.028..-0.058, cap -0.060, LED -0.063. fork outer -0.026 ✓ flange -0.025..-0.029 ok.\n\nSimilarly elbow gearbox: fork outer 0.035 → flange y0.0365 spans 0.0345..0.0385, housing y0.049 spans 0.039..0.059, cap y0.062, collar y0.066, hex y0.069. Motor elbow: flange -0.0365, housing y-0.052 spans -0.0375..-0.0665? depth0.028: y-0.052±0.014 → -0.038..-0.066; cap -0.0685; collar -0.072; LED -0.075. Adjust cable endpoints: c2 end (E.x,-0.070,E.z+0.006)? motor cap at -0.0685: end (E.x,-0.069,E.z+0.004). c3 start (E.x+0.003,-0.069,E.z+0.008)?? start near cap top. ok.\n\nShoulder: cheeks outer ±0.050. Gearbox(+Y): flange y0.0515 d0.003, housing y0.0645 d0.024 spans 0.0525..0.0765 r0.032, cap y0.080 d0.007 r0.020, collar y0.0855 r0.013, hex y0.088. Motor(-Y): flange y-0.0515, housing y-0.077 d0.048 spans -0.053..-0.101 r0.024, cap y-0.104, collar y-0.1085, hex -0.111. Pin d0.19 spans ±0.095 ends inside cap/collar zones ✓. c1 start (0,-0.107,0.156).\n\nWrist block between forks: v ±0.017 vs fork inner ±0.018 ✓.\n\nRoll actuator r0.0145 vs wrist fork plates at y±0.018..0.026: actuator at v=0 plane ✓ no clash; but actuator cylinder extends back to W+u3*0.002 → near block ✓.\n\nCheck roll actuator vs link2 fork plates: plates extend u2 to W+0.017 at y±0.018..0.026, w extent ±0.017 around... plates are boxes dims (0.046,0.008,0.034) in frame(u2,v,w2) centered W-u2*0.006 → w2 extent ±0.017. Actuator along u3 = u2 rotated -28° about v: from W going +u3. Does actuator (r0.0145) hit plates? Plates occupy y 0.018..0.026 & -0.026..-0.018; actuator radius in v = 0.0145 < 0.018 ✓ clears.\n\nWrist rotation: block r0.016 rotates between forks ✓ clearance 0.001 ✓.\n\nGripper body at s0.047.. vs fork plates end u2 W+0.017: body center along u3 from W: W+u3*0.065; nearest body point to W: s0.047 at v0: fine.\n\nNow confirm gripper body doesn't hit desk: lowest body point: s0.047 z = 0.165-0.9553*0.047=0.1201 minus w3/z extents ~0.02 → ~0.10 ✓.\n\nFingertips z 0.041 ✓.\n\nAll good. Also object at (0.4687, 0): on desk ✓ within desk x range ✓.\n\nCamera target maybe (0.22,0,0.18). Fine-tune: set target (0.21,0.0,0.18).\n\nAlso add subtle floor shadow catcher? cycles shadows natural.\n\nLet me write the code now in full. I'll be meticulous with syntax.\n\nAlso remember: after all building, `bpy.context.view_layer.update()`.\n\nOne more consideration: benchmark GLB includes \"contestant camera\" ✓ scene.camera set.\n\nAlso for orbit render, lighting works all around? Rim from +Y back; orbit from behind gets some light from rim/top ✓ plus world ambient 0.35 ✓.\n\nWrite code:\n\n```python\nimport bpy, math\nfrom math import sin, cos, pi, radians, atan2\nfrom mathutils import Vector, Matrix\n\nscene = bpy.context.scene\n# wipe\nbpy.ops.object.select_all(action='SELECT')\nbpy.ops.object.delete(use_global=False)\n\n# render setup...\n```\n\nThen materials, helpers, build.\n\nI'll now write out fully, keeping track of every variable.\n\nFor mats:\n```\ntitanium = mat_principled('Strut_Titanium',(0.60,0.61,0.64),1.0,0.34)\nalu = mat_principled('Alu',(0.78,0.79,0.81),1.0,0.22)\nalu_dark = mat_principled('AluDark',(0.15,0.16,0.18),0.9,0.32)\nsteel = mat_principled('Steel',(0.42,0.43,0.46),1.0,0.18)\naccent = mat_principled('Accent',(0.82,0.26,0.045),0.85,0.30)\ncablem = mat_principled('Cable',(0.012,0.013,0.015),0.0,0.55)\npadm = mat_principled('Pad',(0.85,0.38,0.06),0.0,0.5)\ndeskm = mat_principled('Desk',(0.80,0.79,0.76),0.0,0.38)\nfloorm = mat_principled('Floor',(0.66,0.66,0.68),0.0,0.55)\nboxm = mat_principled('Controller',(0.05,0.05,0.06),0.3,0.42)\nledg = mat_principled('LEDG',(0.02,0.08,0.03),0,0.4, emission=(0.15,1.0,0.35), estr=8)\nleda = mat_principled('LEDA',(0.08,0.04,0.01),0,0.4, emission=(1.0,0.5,0.1), estr=8)\nmemb = membrane material with noise\n```\n\nmembrane mat function with noise — inline.\n\nLet me write the entire script.\n\nAlso add tiny bolts on gripper finger roots? pivot pins exist ✓.\n\nAlso small gusset: link between carriage and finger root — finger plate overlaps carriage ✓.\n\nAlso add two screws on each finger plate outer face holding pad? pads have no visible fasteners — add micro bolt on pad outer? Pads outer face covered by plate (pad between plate inner? pad mounted on inner face). Add 2 micro bolts through plate into pad on outer face at pad location: bolts axis v at plate outer faces y=±(0.017+0.00225)=±0.01925 at s0.120/0.128 w3±0.003. Simple: two bolts per plate: positions W+u3*s ± w3*0.003 + v*(±0.0193), axis v (outward). r0.0016 h0.002 steel. Adds \"replaceable pads\" believability ✓.\n\nbolt() places washer+head from surface point along axis: pass p at surface, axis outward (0,±1,0).\n\nNow finalize quantities & write.\n\nFor the cove normals & smooth: set polys smooth? flat is fine; with smooth shading profile curve smooths: set smooth True for all → the flat floor part would try smooth with wall across edge? Subsurf not used; smooth shading on quads interpolates normals — floor to curve transition would shade oddly at the seam vertex but since curve dense it's fine; flat also fine. Use smooth.\n\nAlso floor mat: give slight roughness 0.6.\n\nAlso may add contact shadow strengthening via light? skip.\n\nWrite code — also include a second tiny detail: desk has a faint groove? skip.\n\nAlso the \"small machined object\" described ✓.\n\nCheck total strut node count: strut1 n=12 → 26 verts; skin apply → mesh ~ (26*8?) fine.\n\nNow produce final answer code. Careful with:\n\n- `me.skin_vertices[0].data` after adding modifier & update.\n- When applying modifier, object must be in view layer & active ✓.\n- After apply, polys exist.\n\nFor membranes, `from_pydata(verts, [], faces)` ✓.\n\nAlso create cable curves — GLB may or may not include; benchmark handles conversion best-effort.\n\nLet me also ensure I don't shadow builtin names.\n\nTime to write. I'll aim for clarity & correctness over brevity.\n\nOne more check: `bpy.ops.mesh.primitive_torus_add` minor_segments param name `minor_segments` ✓ major_segments ✓.\n\nLED helper:\n\n```python\ndef led(name, p, axis, mat, r=0.0022):\n    a=Vector(axis).normalized()\n    cyl(name+'_bz', r*1.7, 0.0018, Vector(p)-a*0.0005, axis, alu_dark, verts=24, bevel=0)\n    cyl(name+'_c', r, 0.0012, Vector(p)+a*0.0008, axis, mat, verts=16, bevel=0)\n```\n\nFine.\n\nCyl default verts 48 for big parts; small use 24.\n\nNow writing the code end-to-end.\n\ndef rod(p1,p2,r,mat,name,verts=12): d=Vector(p2)-Vector(p1); cyl(name, r, d.length, (Vector(p1)+Vector(p2))/2, axis=d.normalized(), mat=mat, verts=verts, bevel=0, smooth=True)\n\nBut cyl signature order — define cyl(name, r, depth, loc, axis, mat, verts, bevel, smooth).\n\nAlso box(frame=None).\n\nAlso note: when passing axis to cyl with default (0,0,1) frame_from_axis gives identity-ish: z=(0,0,1), t=(0,0,1)? abs(z.z)=1 → t=(1,0,0): x=z×t=(0,1,0)? z×t = (0,0,1)×(1,0,0) = (0*0-1*0, 1*1-0*0, 0-0)=(0,1,0); y=z×x=(0,0,1)×(0,1,0)=(-1,0,0). Matrix columns x=(0,1,0),y=(-1,0,0),z=(0,0,1) det=+1 ✓ fine (rotated 90° about Z, irrelevant for cylinders).\n\nBolt heads verts=6 rotation arbitrary ✓.\n\nNow, strut function code:\n\n```python\ndef optimized_strut(name, A, B, dA, dB, rA, rB, bend, n, mat):\n    A=Vector(A); B=Vector(B)\n    u=(B-A); L=u.length; u.normalize()\n    v=Vector((0.0,1.0,0.0))\n    w=u.cross(v).normalized()\n    v=w.cross(u).normalized()\n    def prof(t): return 0.60+0.55*(abs(cos(pi*t))**0.75)\n    def hfun(t): return (dA+(dB-dA)*t)*0.5*prof(t)\n    def rfun(t): return (rA+(rB-rA)*t)*(1.30-0.50*sin(pi*t))\n    def center(t): return A+u*(L*t)+w*(bend*sin(pi*t))\n    verts=[]; edges=[]\n    for i in range(n+1):\n        t=i/n; C=center(t); h=hfun(t)\n        verts.append(C+w*h); verts.append(C-w*h)\n    for i in range(n):\n        a=2*i\n        edges.append((a,a+2)); edges.append((a+1,a+3))\n    edges.append((0,1)); edges.append((2*n,2*n+1))\n    diag=set()\n    for i in range(n):\n        a=2*i\n        if i%2==0: diag.add((a,a+3))\n        else: diag.add((a+1,a+2))\n    mid=n//2; a=2*mid\n    diag.add((a,a+3)); diag.add((a+1,a+2))\n    for e in diag:\n        edges.append((min(e),max(e)))\n    radii=[]\n    for i in range(n+1):\n        r=rfun(i/n); radii += [r,r]\n    me=bpy.data.meshes.new(name)\n    me.from_pydata([tuple(p) for p in verts], edges, [])\n    ob=bpy.data.objects.new(name,me)\n    bpy.context.scene.collection.objects.link(ob)\n    sk=ob.modifiers.new('Skin','SKIN')\n    bpy.context.view_layer.update()\n    sv=me.skin_vertices[0].data\n    for i,d in enumerate(sv): d.radius=(radii[i],radii[i])\n    sv[0].use_root=True\n    bpy.ops.object.select_all(action='DESELECT')\n    ob.select_set(True); bpy.context.view_layer.objects.active=ob\n    bpy.ops.object.modifier_apply(modifier=sk.name)\n    for p in me.polygons: p.use_smooth=True\n    sub=ob.modifiers.new('Sub','SUBSURF'); sub.levels=2; sub.render_levels=2\n    me.materials.append(mat)\n    tops=[verts[2*i] for i in range(n+1)]; bots=[verts[2*i+1] for i in range(n+1)]\n    return dict(obj=ob,u=u,v=v,w=w,A=A,L=L,n=n,tops=tops,bots=bots,center=center,hfun=hfun,rfun=rfun)\n```\n\nWait diag edges (a, a+3): top_i to bot_{i+1}: indices top_i=2i, bot_{i+1}=2(i+1)+1=2i+3 ✓. (a+1,a+2): bot_i to top_{i+1} ✓.\n\nX at mid adds both diagonals — one may duplicate existing: set handles.\n\nDuplicate rail/edge none.\n\nMembrane:\n\n```python\ndef membrane(name, strut, bay, mat, bow=0.0028):\n    tops=strut['tops']; bots=strut['bots']; nrm=strut['v']\n    c00=bots[bay]; c10=bots[bay+1]; c11=tops[bay+1]; c01=tops[bay]\n```\nOrder for consistent bilinear: P00=c00(bot i), P10=c10(bot i+1), P11=c11(top i+1), P01=c01(top i) ✓ quad loop faces as built.\n\n inset 0.07.\n\nClips:\n\n```python\ndef cable_clip(name, st, t, off, mat):\n    u=st['u']; v=st['v']; w=st['w']\n    C=st['center'](t); surf=st['hfun'](t)+st['rfun'](t)\n    depth=off-surf+0.006\n    loc=C-w*((surf+off)/2)\n    return box(name,(0.012,0.020,depth),loc,frame=(u,v,w),mat=mat,bevel=0.002)\n```\n\nCable point helper:\n\n```python\ndef strut_cable_pts(st, off, ts, voff):\n    return [st['center'](t)-st['w']*off+st['v']*voff for t in ts]\n```\n\nFull cable2 pts: [grommet pt] + pts at ts [0.12,0.3,0.55,0.78,0.9 with voff lerp] + end. For last segment voff transitions to motor y; simpler: build pts list manually:\n\n```python\npts=[(0.012,-0.026,0.104)]\npts+=strut_cable_pts(s1,0.072,[0.10,0.28,0.52,0.74],-0.026)\npts+=[Vector((E.x,-0.05,E.z))+... ]\n```\nend: (E.x, -0.069, E.z+0.004). Add mid transition pt: s1 center(0.92) - w1*0.06 + v*(-0.05).\n\nOk good enough; AUTO handles smooth.\n\nLet me write the final code block now. Also add `random`? not needed.\n\nDouble-check `mat_principled` emission inputs exist in 5.1: 'Emission Color','Emission Strength' ✓.\n\nCoat: 'Coat Weight' ✓.\n\nAlso desk: maybe two-tone: add thin darker edge band? skip.\n\nFinal: camera slight adjust: loc (1.00,-1.30,0.58), target (0.21,0.0,0.175), lens 60.\n\nAlso set `scene.render.resolution_percentage=100`.\n\nAlso transparent film? no.\n\nNow — write it all out carefully. I'll count on ~450 lines. Ensure no f-string issues, all Vector math with Vector().\n\nPotential pitfall: box() with frame passed — set_frame expects vectors; pass tuple of Vectors.\n\nIn bolt_ring, basis from frame_from_axis(axis) → x,y in plane ✓.\n\nFor micro bolts on collar faces: ring_r small.\n\nAlright, also verify thrust washers don't clash with hub cylinder at shoulder: washers r0.0135 at y±0.0305 z0.165 axis Y depth0.003: hub r0.026 → hub surface reaches y±0.026 at A1; washers between 0.026..0.036 ✓.\n\nElbow: eye box y ±0.018; washers ±0.0215 ✓ inner fork ±0.025 ✓.\n\nWrist: block v ±0.017; washers ±0.0175? fork inner ±0.018 → washer depth0.002 at y±0.0175 spans 0.0165..0.0185 overlaps both slightly — set y±0.0175 depth0.0015 → 0.01675..0.01825 slight overlap with block (0.017) — negligible/intentional press fit. Fine.\n\nNow code. Also after building everything, select none.\n\nOne more: \"no exposed corrugated pipes\" ✓ none.\n\nI'll write the script now.\n\nAlso: `scene.cycles.use_denoising=True` default fine.\n\nAlso possible: `scene.render.engine='CYCLES'` then benchmark overrides anyway.\n\nCheck `primitive_cube_add(size=1)` then dimensions then apply scale ✓.\n\nBevel width relative small dims: clamp width < min(dims)/2.5 — choose widths carefully per call.\n\nFor nameplate dims (0.05,0.002,0.010) bevel 0.0006.\n\nWriting final.\n\nAlso — include a faint large softbox reflection helper? Not needed with area lights (they reflect in metals ✓ premium).\n\nI think code is ready to write. Let me draft it completely in my head onto the answer, being careful.\n\nAlso: after creating many objects via ops, active object changes — box()'s transform_apply uses active ✓ since just created.\n\nEdge: `bpy.ops.object.transform_apply(location=False, rotation=False, scale=True)` with rotation set later via matrix — but I set location at creation then apply scale only; then set_frame sets full matrix ✓.\n\nFor boxes with frame, dimensions applied in local axes then framed ✓.\n\nTorus smooth: set all polys smooth.\n\nMaterials appended: `o.data.materials.append(mat)`.\n\nNow final answer.\n\nOne more check on membrane normals for Cycles transmission: double-sided ok.\n\nAnd GLB: solidify on membrane gives real thickness ✓.\n\nSave blend path: use `os.path.join(os.path.expanduser('~'), ...)`? Keep `bpy.path.abspath('//')` fallback tmp? Just try '//robotic_arm.blend' except pass. Actually if blend never saved, '//' resolves to cwd of process — fine.\n\nWrite it.","reasoning_details":[{"type":"reasoning.text","text":"Let me carefully plan this Blender scene.\n\nThe task: A desk-mounted robotic arm with at least 4 articulated joints, mid-reach toward a small machined object on a desk. Key design features:\n\n1. **Topology-optimized struts** on the elongated structural links between joints — organic metal members with branching transitions, lattice openings, voids. NOT on joints/base/wrist/gripper.\n2. **Precision mechanical joints**: cylindrical housings, bearings, bolted flanges, hinge pins, gearboxes, brackets, covers, interface plates. Clean base with rotating platform.\n3. **Clean cabling**: slim black lines, controlled routing.\n4. **Translucent technical membrane** spanning some openings in optimized struts (translucent TPU-like).\n5. **Two-finger parallel gripper** — machined solid, replaceable pads, pivots.\n6. **Believable mechanics**: visible rotational axes, tapering from heavy base to smaller wrist.\n7. **Setting**: clean studio/robotics lab, desk, small machined object, premium lighting.\n\nLet me think about how to build topology-optimized looking struts procedurally in Blender Python without booleans becoming a mess. \n\nApproach for organic optimized struts: Build them as a \"bone-like\" structure — a central spar with branching web members connecting two or three rails, with smooth joints. A good way: create a tapered, slightly curved main beam using metaball-like skinning? Actually a robust method: create multiple tapered tubes (curves with bevel) that split and merge — like a \"Y\" branching pattern along the length. To make it look topology optimized, the strut can be made of 2-3 longitudinal rails connected by diagonal webbing with varying thickness, plus smooth fillets.\n\nAlternative: Use the Skin modifier on a mesh skeleton with varying radii, then Subdivision Surface. That gives organic branching forms nicely. The Skin modifier approach: build an edge graph (vertices connected by edges), assign per-vertex radii, add Skin modifier → generates manifold mesh, then Subsurf level 2, smooth shading. That creates genuinely organic-looking branching topology-optimized structures. This is robust headless.\n\nPlan for a strut between joint A and joint B (in local coordinates, say along X axis from (0,0,0) to (L,0,0)):\n- Skeleton: two main rails top and bottom (offset ±r(z) in Z), maybe with X-bracing or a zigzag web between them, plus a center spine? For \"topology optimized\" look, typical designs have a tapering I-beam-like shape with organic holes. A two-rail ladder with diagonal struts and smooth branching gives that look.\n- Nodes along length: at parameter t = 0, 0.2, 0.4, ... rails at z = ±h(t) where h varies (wider near ends where loads transfer, thinner mid, or vice versa). Actually topology-optimized beams often have material concentrated near joints with voids in the middle. Let's do rails that are thicker near the ends, with the gap between rails larger near ends (deeper section) and smaller mid-span, with a few diagonal cross-links forming a triangulated web.\n- Add occasional small openings within rails? The Skin approach creates openings between rails already (the voids). \"Controlled lattice openings, carefully shaped voids\" — the ladder/triangulation gives elongated voids between members. Good.\n\nTo add a bit more \"grown\" feel, make rails slightly bowed (catenary-like curve) and add a short diagonal member that branches off and merges (like an X in the middle). Radii per node vary smoothly.\n\nThen membrane panels: for selected struts, span some of the openings with thin translucent panels — e.g., create a flat-ish mesh matching the opening outline between two adjacent segments (quad openings), solidify thin, translucent TPU material (transmission 0.7, roughness 0.3, slight tint). Attach slightly inset. Only on some openings.\n\nJoints: build from cylinders — housing (large cylinder along axis of rotation), bearing ring (torus or short cylinder), flange with bolts (cylinder + small bolt cylinders arranged in circle), gearbox (box or short wide cylinder), caps. Rotary actuator: cylinder + smaller cylinder shaft + end cap with cable port.\n\nStructure of the arm (4+ joints):\n- J1: base rotation (vertical axis) — base bolted to desk: base plate (rounded box), bolted flange with 6 bolts, rotating turret platform, rotary actuator housing (vertical cylinder).\n- J2: shoulder pitch (horizontal axis) — on top of turret, two side brackets/cheeks with bearing housings, hinge pin visible; first link (lower arm strut) goes up.\n- J3: elbow pitch — similar bearing housing; second link (upper arm, topology-optimized).\n- J4: wrist pitch — smaller; short forearm link.\n- J5: wrist roll — small rotary actuator; then gripper mount.\n- Gripper: two-finger parallel — a small gearbox body, two sliding finger rails, L-shaped machined fingers with pads; maybe small linkage.\n\nPose mid-reach: base at origin on desk (desk at z=0? let's set desk top at z=0, base sits on it). Arm reaches forward toward a small object (e.g., a small machined metal cube/cylinder part, like a knurled knob or a bearing block) on the desk ~0.55 m away.\n\nDimensions: desk at z=0. Base ~0.14 m tall, arm reach total ~0.6-0.7 m. Scale everything in meters.\n\nLet me define joint positions via a simple FK chain:\n- Base center at (0, 0, 0). Base plate on desk.\n- J1 axis vertical at z ~ 0.10. Turret rotates so arm faces +X direction (toward object at +X).\n- J2 (shoulder) at (0, 0, 0.20) approx, axis along Y.\n- Link 1 (upper arm) length L1 = 0.34, angle from vertical: leaning forward ~35°.\n- J3 (elbow) at end of link1.\n- Link 2 (forearm) length L2 = 0.30, angled down-forward so wrist approaches object height ~0.06 above desk.\n- J4 wrist pitch at end of link2; wrist roll then gripper pointing down-forward toward object.\n\nCompute: shoulder at (0,0,0.22). Link1 at angle θ1 from vertical toward +X: 40°. Elbow at (sin40*0.34, 0, 0.22+cos40*0.34) = (0.2186, 0, 0.4804). Hmm that's fairly high. Link2 angle from vertical: 75° forward (i.e., mostly horizontal pointing down?). Let's param angle from vertical downward... Let me param: link2 direction making angle φ from horizontal. Want wrist at roughly (0.52, 0, 0.10). From elbow (0.219, 0, 0.480): delta = (0.301, -0.380), length = sqrt(0.0906+0.1444)=sqrt(0.235)=0.485 — too long for 0.30. Adjust: bring object closer: object at (0.45, 0, 0.02). Wrist target (0.42, 0, 0.09). Delta from elbow: (0.201, -0.390), len = sqrt(0.0404+0.1521)=0.439. Still >0.30. So either longer L2 or lower shoulder/elbow.\n\nLet me choose: shoulder height 0.19, L1 = 0.30 at 50° from vertical: elbow at (0.30*sin50, 0, 0.19+0.30*cos50) = (0.2298, 0, 0.3828). L2 = 0.32. Wrist target (0.44, 0, 0.10): delta (0.2102, -0.2828), len = 0.3523. Slightly over. Wrist (0.42,0,0.12): delta (0.1902,-0.2628) len 0.3244 ≈ L2 0.32. OK close enough — tune precisely in code by computing the direction and placing wrist at elbow + dir * L2, then place the object near gripper tip accordingly. Better: compute gripper tip from FK, then place the small object just in front of/below the gripper tip on the desk. That guarantees \"reaching toward a small object\" alignment. I'll compute positions in Python with math.\n\nGripper: from wrist, a short tool flange + gripper body length ~0.07, fingers extend ~0.05. The fingers point along link2 direction continued (with wrist pitch adjusting to aim slightly downward at object). Simplify: wrist pitch axis Y, then tool direction = link2 direction rotated by a small angle so the gripper points down toward the object at ~ 30° below horizontal.\n\nSimplification for robustness: I'll compute angles numerically:\n- dir1 = angle a1 from vertical (forward +X). \n- Elbow E = S + L1*(sin a1, 0, cos a1).\n- Choose wrist W explicitly = (0.42, 0, 0.115). Then a2 direction = normalize(W-E). Gripper axis direction d3 = rotate toward object: aim at object O on desk: d3 = normalize(O - (W + small offset)). Gripper length ~0.11 from W to fingertips. Set object O such that fingers hover just above/around it: fingertips at W + d3*0.12, object at fingertips + d3*0.02 minus desk offset... Actually to avoid intersection with desk, place object on desk (z = object height/2 ~ 0.02), and fingertips slightly above desk: fingertip z ~0.035, object height 0.03. Let me just place fingertips at z≈0.045 and object directly below fingertips plus a bit forward. Fine.\n\nNow details for each component.\n\nMaterials:\n- Optimized struts: bead-blasted titanium / aluminum — metallic 0.95, roughness 0.32, light gray with slight warm tint. Maybe subtle anisotropy.\n- Joint housings: machined aluminum — metallic 1.0, roughness 0.22, light silver; some darker anodized parts (dark gray, metallic 0.9 roughness 0.3); accent anodized orange or blue small rings for design flair (research prototype look — e.g., orange accent rings).\n- Bearings: dark steel.\n- Bolts: steel with slight roughness 0.25.\n- Membrane: translucent TPU — Principled: Transmission weight 0.85, roughness 0.35, IOR 1.4, base color slightly smoky (0.9,0.93,0.95), alpha? In Cycles use transmission; thickness via Solidify. For GLB export, transmission maps to alpha blend-ish; okay best effort. Maybe give slight tint amber? Keep neutral smoky.\n- Cables: black rubber — roughness 0.6, near black.\n- Gripper pads: dark rubbery or brass contact pads — use amber/orange urethane pads.\n- Desk: matte light warm gray or pale wood? \"clean contemporary design studio\" — desk in matte light gray/white laminate with subtle bevel. Maybe a soft oak? Keep light neutral gray.\n- Background: large soft cyclorama — a curved backdrop plane (sweep from floor to wall) in light warm gray, or just world + big area lights. A studio backdrop: floor plane + wall with curved transition. Build with a mesh and bevel, or simply large floor plane and rely on world light gray. I'll build a curved backdrop (cove) mesh — looks premium.\n- Small object on desk: a precision machined part — e.g., a small stepped cylinder \"knob\" with knurled band (knurl via torus with small teeth? or just grooves via torus stack), aluminum with orange anodized ring. Make it look like a machined demo part: stepped puck with a hex top? A small hex-socket cap shape. Keep simple: stepped cylinders + torus groove + a small hex head on top (cylinder 6 verts). \n\nLighting: \n- Key: large area light upper-left front, warm-neutral 5500K, soft.\n- Fill: area light right, cooler, dimmer.\n- Rim: area behind/top for edge highlight.\n- Plus a soft overhead area. World: light gray 0.05-0.08 strength or use gradient via world color. Keep world slightly gray (0.3 strength gray) for ambient.\n- Maybe a subtle spotlight on object? Not necessary.\n\nCamera: square 1536. Position to show arm side-front 3/4 view: object to the right of frame, base left. Arm extends along +X; camera at about (1.15, -1.05, 0.62) looking at (0.28, 0, 0.26)? Let me think: keep both base and object in frame with some margin. Arm spans x from -0.1 to 0.55. Frame center ~ (0.22, 0, 0.22). Camera at (0.95, -1.15, 0.55) with 70mm lens? For product look, use 70-85mm equivalent, camera farther: (1.6, -1.9, 0.95) aiming at (0.2, 0.05, 0.24). I'll compute track-to with constraint or manual rotation via look-at function. Write a helper `look_at(obj, target)`.\n\nAlso add desk as a rounded slab: big rounded cube (bevelled) top at z=0, e.g., 2.2 x 1.4 x 0.06, top z=0 so body extends down. Position desk so arm near one end, maybe include subtle desk edge in frame. Also a second small prop? Maybe a small parts tray or a second object — keep minimal: the target object plus maybe a tiny washer nearby. Also a control box? Keep it clean: just the arm + object + desk. Maybe add a slim cable from base to a small control module box at the desk rear — shows \"controlled cable routing\". A compact black controller box with a slim cable to base. Good detail, keep it tidy with a curve cable that hugs the desk.\n\nAlso recessed cable guides along arm: run one slim black cable along the struts using small clip rings — curve with bevel, clipped at 2-3 points per link with small torus/clip mounts. Keep it close to the structure, inner side.\n\nJoint construction details:\n\nBase assembly:\n1. Desk-mounted base plate: rounded square plate 0.16 x 0.16 x 0.012 at z=0.006, dark anodized, with 4 counterbored bolts at corners (small cylinders + hex heads).\n2. Lower base housing: cylinder r=0.055, h=0.03 on plate; chamfer (bevel modifier applied or use bevelled cylinder by adding bevel modifier and applying? For headless robustness, apply bevel modifier via modifier stack then apply). Actually simpler: use bevelled cylinders via bevel modifier with segments 2-3, apply. I'll write helper `bevel(obj, width, segments)` applying modifier.\n3. Bearing ring: torus or short cylinder r=0.05 at z=0.045, darker steel.\n4. Rotating turret: cylinder r=0.048 h=0.035 + top interface plate; accent ring (orange anodized) thin torus between base and turret — subtle.\n5. On turret: shoulder joint housing — two cheek plates (rounded boxes) flanking the arm root, with cylindrical bearing caps on outer faces (axis along Y). Hinge pin visible: cylinder along Y through both cheeks, with end caps + bolts.\n6. Cable port at back of turret with a slim cable loop down to base port (internal channel look) — small curve.\n\nShoulder joint (J2): housing cylinders along Y: main housing r=0.032 length 0.075 (through both cheeks), bearing caps r=0.026, end caps with 4 small bolts each, center gearbox cylinder r=0.036? Hmm widths: cheeks at y=±0.045. Housing spans y=-0.06..0.06.\n\nLower arm strut (Link 1): topology-optimized member from shoulder (J2) to elbow (J3). Attach via interface plates at each end: small machined hub cylinders at both ends that the organic strut visually grows out of. Strut skeleton in local frame, then orient. Build the strut geometry in world space directly by computing positions along the segment from J2 to J3 (minus hub lengths). Helper function `make_optimized_strut(p_start, p_end, width_start, width_end, thickness...)`.\n\nStrut skeleton design (per strut): local axis u (from A to B), with side vectors v (lateral) and w (vertical-ish). Rails: two rails offset in ±w (in the plane of bending — the arm's bending plane is XZ, so w = in-plane perpendicular; rails top and bottom of the beam section). Optionally a third element: diagonal webbing zigzag between rails. Node count n=9 along length. Rail offset h(t) = base + bulge: h(t) = mix(hA, hB, t) * (1 + 0.35*sin(pi*t))? Actually topology-optimized look: deeper near middle or ends? Real TO brackets often deeper where moment is high (near fixed end) — make depth larger near ends, pinched mid? Let's do: depth d(t) = lerp(dA, dB, t) * (0.75 + 0.5 * (cos(2π t)*0.5+0.5))? That gives max at ends, min mid — creates an hourglass beam with big openings mid — looks organic. With diagonal webbing crossing the void.\n\nRadii: rail radius r(t) = lerp(rA, rB, t) * (1 - 0.25*sin(pi t))? Thinner at mid? Or keep thicker at nodes (joints) and thinner between — organic bone look: nodes slightly swollen (like bone knuckles). Per-vertex radius: base(t) * (1 + 0.3 * bump at attachment zones).\n\nEdges: rails as chains; diagonals connecting top node i to bottom node i+1 alternating (zigzag), plus maybe an X at the middle bay. Add short horizontal cross-members between rails at t=0 and t=1 (the attach hubs merge into rails).\n\nSkin modifier: add, then set each vertex's skin radius (via `obj.data.skin_vertices[0].data[i].radius = (rx, ry)`). Then add Subsurf (level 2) and smooth shading. Also mark root? Skin modifier needs a root vertex usually for correct generation in some contexts but for pure mesh generation it works without armature; set `mark_root` maybe not needed. Known: Skin modifier works on edges; need at least one vertex marked root when used with armature but for geometry it's fine. I'll mark vertex 0 as root to be safe.\n\nThen add membrane panels on selected bays: quads connecting top node i..i+1 and bottom node i..i+1 where there's no diagonal crossing (or over the diagonal? a panel over an opening with diagonal inside shows \"lightly revealing structure beneath\" — nice: translucent panel over a bay that has a diagonal strut). Panel: create quad slightly inset (scale 0.9 toward bay center), solidify 0.0015m, subsurf 2 with supporting loops? Simpler: quad with slight outward bow — make it a grid 4x4 with slight offset along normal, subsurf 2. Or just flat quad with Solidify + Bevel — flat taut film is fine (\"tensioned mesh/film\"). I'll make slightly bowed panel (bulge 3mm) via subdivided grid + subsurf, gives taut tensioned look. Solidify after subsurf. Keep membrane only on 2-3 bays of link1 and maybe 1-2 of link2; leave others open.\n\nElbow joint (J3): similar to shoulder but smaller: hinge axis Y, housing r=0.026, cheeks on link1 end or on link2? Make elbow: link1 end has fork cheeks; link2 root has central hub that rotates between them; hinge pin through; bearing caps outside; small gearbox/motor cylinder attached on side (r=0.02, axis Y, extends y+) with cable.\n\nForearm strut (Link 2): smaller TO strut from elbow to wrist pitch, with its own hubs.\n\nWrist (J4): pitch joint small housing r=0.018 axis Y; then wrist roll (J5): small rotary actuator cylinder along tool direction r=0.016 length 0.03 with accent ring; then tool flange (disc with 4 bolts) then gripper.\n\nGripper: \n- Gripper body: small rounded box (0.05 x 0.035 x 0.03) with a front slot.\n- Two finger carriages: small boxes on rails, spaced ±0.012 in Y (parallel gripper opens laterally). Rails: two slim cylinders along Y spanning body front? Parallel gripper: fingers move toward/away along Y. Fingers: L-shaped machined plates: from carriage extend forward (along tool dir) 0.045 as flat plates 0.006 thick in Y, then pads on inner faces at tips: small blocks 0.008 with orange urethane pads.\n- Visible pivots/actuation: small servo cylinder on top of body + tiny linkage rods? Keep believable: a compact linear actuator (small cylinder) on the back driving a wedge — visually: small motor cylinder on body top + a pair of tiny pin joints on fingers. Also add small bolts.\n- Fingers solid machined — boxes with bevel, no lattice.\n\nCable routing: \n- One main cable: from base rear port up the inside of link1 (clips at 2 points) to elbow motor, another from elbow along link2 to wrist. Use curves bevel_depth 0.0022, black. Keep tight to structure: compute path points offset from strut centerline toward -w (inside). Clips: small torus around? Simpler: small dark clamps (tiny boxes) at clip points. Good enough.\n\nRotational axes visibility: hinge pins with contrasting end caps (orange ring + steel cap) on both sides; bolts circles on caps.\n\nNow the desk & studio:\n- Desk slab: 2.4 x 1.3 x 0.05 rounded (bevel 0.02), top z=0, centered maybe at (0.3, 0.1, -0.025) so base near back-left region and camera sees front edge. Actually base at origin; desk center at (0.25, -0.05, -0.026), size 1.9 x 1.1. Keep desk edges within/around frame.\n- Backdrop: a large curved cove behind: floor plane big + wall; or seamless cyclorama mesh: I'll build a profile curve extruded: floor from y=-? Hmm orientation: camera looks from -Y toward +Y? Camera at y=-1.9 looking at origin → background at +Y. Cove: floor extends from y=-3 to y=+2.5 at z=-0.05 (under desk? desk sits on floor? Desk is the table; floor below at z=-0.85 with desk legs? Simpler: present the desk as a floating studio surface? Task says \"desk-mounted ... on a desk\". Give desk visible legs? A clean studio table: slab + 2 panel legs or a single panel leg. To keep composition at 1536² with arm ~0.5m tall, showing legs means wide framing. Alternatively frame crop: desk fills lower frame, backdrop cove directly behind/under desk (like desk in front of studio sweep, floor not visible). I'll put the cove right behind the desk and let the desk slab extend to the frame bottom — camera slightly above looking down a bit, desk surface visible, wall cove behind. Desk thickness visible at front edge. No legs needed if cropped — but 360° orbit view! The benchmark also renders a 360 orbit. So the scene should look complete from all sides: give the desk legs (panel legs or cylindrical) and a floor. Let's do: floor at z=-0.78 (desk height ~75cm), desk slab with 4 slim round legs or 2 panel legs. Panel legs (rounded boxes) look studio-modern. Floor: big plane with subtle roughness, light gray. Backdrop wall at y=+2.2 tall. Or cove curve. I'll build floor plane 20x20 and a curved cove wall behind (y>1.2) — but orbit from other sides would see wall edge. Use a full room? For a 360 orbit, typical studio: infinite white-ish floor with soft radial gradient and world gray — acceptable. I'll do: big floor plane (light warm gray, roughness 0.5), plus a large background cylinder? A giant cylinder around (r=6) interior lit gives seamless look from all directions. Could look odd. Simplest robust: floor plane + world light gray; horizon naturally fades. With filmic/agX, looks clean studio. Also add subtle dark vignette via compositor? Not needed.\n\nAdd desk legs: two panel legs near ends.\n\nSmall object: at computed target: a machined part — base puck r=0.018 h=0.008, shaft r=0.010 h=0.012, top hex r=0.012 h=0.008 (6-gon), anodized blue? Keep aluminum + one orange ring. Also a tiny washer beside? Place a second small part: a small bearing (torus + ring) lying near — nice for \"picking up small desk objects\" context. Keep 1 main target + 1 small extra.\n\nAlso add a compact controller box on desk behind base with cable: box 0.09x0.06x0.03 dark, small LED (emissive dot), slim cable to base. Cable: curve lying on desk, neat straight-ish with gentle bend. Adds lab believability. Status LEDs on joints: tiny emissive dots (green/amber) — nice research-prototype touch, small.\n\nNow materials via helper `mat_principled(name, color, metallic, roughness, ...)`.\n\nBevel helper: apply bevel modifier. In Blender 5.1, `bpy.ops.object.modifier_apply` requires context override or use `bpy.context.view_layer.objects.active`. Headless fine with `bpy.context`.\n\nShading smooth: for cylinders set `data.polygons foreach set use_smooth`? Use `for p in obj.data.polygons: p.use_smooth = True` then add weighted normals via bevel modifier's `harden_normals`? WeightedNormal modifier exists. Simpler: bevel mod + set smooth + `obj.data.set_sharp_from_angle`? Auto smooth changed in 4.1+. Use smooth shading + bevel; add \"Weighted Normal\" modifier maybe removed? WeightedNormal still exists in 5.x I believe. To be safe: smooth shading + bevel segments=3 looks fine.\n\nCreate cylinder helper: `add_cyl(radius, depth, loc, rot, verts=48)`.\n\nBolts helper: hex head bolt = cylinder(verts=6) small + washer? Just hex head + short shaft. Arrange in circle helper `bolt_circle(center, axis, radius, n, bolt_r, ...)`.\n\nOrientation helpers: rotate cylinder (default axis Z) to axis: use quaternion `Vector((0,0,1)).rotation_difference(dir)`.\n\nSkin strut builder — most complex part. Steps:\n1. Compute frame: u = normalize(B-A); pick w = component of global Z perpendicular to u? The bending plane for links is XZ plane, so side vector v = global Y (0,1,0) mostly; w = u × v normalized. Compute v = normalize(cross(w0? )). Let's set: v = (0,1,0) (lateral, hinge axis direction), w = normalize(cross(u, v)) — in-plane perpendicular. Rails offset ±w * d(t)/2; slight v variation? Keep planar — fine, plus maybe slight lateral flare at ends? Keep planar for cleanliness; add slight bow: rails get extra offset along w by bow(t)=0.02*sin(pi t)*sign to look organically curved (top rail bows up, bottom bows down — already the ±w with varying d gives shape). Additionally make the centerline itself slightly curved: offset c(t) = bend * sin(pi t) along w for whole strut — a gentle arc looks grown. Small amount 0.015.\n\n2. Nodes: n = 10 segments. For i in 0..n: t=i/n; center C = A + u*(L*t) + w*bend*sin(pi*t); half-depth h(t) = (dA + (dB-dA)*t)/2 * prof(t), prof(t) = 0.62 + 0.55*(0.5+0.5*cos(2π t))? That ranges 0.62..1.17 at ends... hmm want depth bigger at ends: prof = 0.6 + 0.55*abs(cos(π t))^0.8? At t=0.5, cos(π/2)=0 → prof=0.6 min mid; ends 1.15. Good: prof(t) = 0.6 + 0.55*abs(cos(pi*t))**0.75.\nTop node T_i = C + w*h(t); bottom D_i = C - w*h(t). Maybe also mid node for triangulation? Diagonals: edges T_i→D_{i+1} for even i, D_i→T_{i+1} for odd i (zigzag). Additionally, add short cross edge T_0—D_0 and T_n—D_n.\n3. Radii: rail node radius rr(t) = (rA + (rB-rA)*t) * (1.25 - 0.5*sin(pi*t))? At mid 0.75x, ends 1.25x. Diagonal nodes share same per-node radius (nodes are shared). Node radii: top nodes get rail radius; diagonal edges use node radii. With shared nodes it's consistent.\nNode radius values: link1: rA≈0.011 at shoulder end, rB≈0.008 at elbow. Depth dA=0.075, dB=0.05.\n4. Extra \"grown\" detail: add a mid-spine? Maybe skip; zigzag gives triangulated organic look. Add one extra diagonal in middle bay making an X.\n5. Mesh: verts list, edges list. Create mesh, skin modifier, set radii per vertex: need `me.skin_vertices` after adding modifier? Skin data: when creating mesh from_pydata, then add Skin modifier — the skin vertex data layer created automatically? In Blender, `mesh.skin_vertices` exists once a Skin modifier is added? Actually the skin vertices data layer is created when modifier added via `obj.modifiers.new(type='SKIN')`. Yes, then `me.skin_vertices[0].data` has one entry per vertex. Set radius. Then Subsurf modifier levels 2. Optionally apply skin then subsurf for membrane fitting? Keep modifiers unapplied (GLB exporter applies modifiers at export — glTF exporter does apply modifiers. Yes, exporter applies modifiers by default. Cycles render also evaluates. Fine.)\n\nPotential pitfall: Skin modifier may produce twisted frames at branch nodes; with smooth radius it's usually fine.\n\nAlso mark loose root: set `sv.use_root = True`? attribute `use_root`? For skin_vertices data each has `use_root`? It's `SkinVertex.use_root`? In bpy, `mesh.skin_vertices[0].data[i].use_root`. Hmm, attribute might be `use_root`. I think it's fine without.\n\nLet me double check: `bpy.types.SkinVertex` has properties: `radius` (float[2]), `use_loose`, `use_root`. Yes.\n\n6. Interface hubs: at each strut end, a machined hub: short cylinder along u (r slightly larger than local depth/2 +0.005? no—hub r ≈ rail attach zone) with flange + bolts connecting to joint clevis. Hub: cylinder r_hub along u length 0.03, plus collar torus, plus 4 bolts on flange face. The strut tips (first/last nodes at t=0,1 with radius rA*1.25) visually merge into hub — position hubs so strut end nodes embed inside hub cylinder.\n\nMembrane panels: choose bays (between node i and i+1) list per strut. Panel quad corners: interpolate rail nodes inset: P = lerp corners toward bay centroid by 0.12 to create margin (film inset within frame, slightly revealing edges). Add slight bulge along ±v? Membrane spans in the plane of the bay (the bay lies in u-w plane; film covers it like a drum). Tensioned film would be flat; slight outward bow ±0.002 along v. Build grid 5x5 with bow = 0.0025*sin(pi*s)*sin(pi*r) along normal v. Subsurf 1? grid dense enough; add Solidify thickness 0.0012. Material TPU translucent. Also maybe perforation? skip.\n\nFor GLB: transmission becomes... glTF exporter exports Transmission as KHR_materials_transmission — good, supported by viewers roughly. OK.\n\nCables as Bezier/NURBS poly curves with bevel. Use bevel_depth and polyline through points with Catmull? Use NURBS or simple bevelled poly spline with many sampled points (smooth via interpolation). I'll create Curve with spline type 'BEZIER' and set handles AUTO for smoothness.\n\nJoint limits detail: add small mechanical stop blocks on joints (tiny tabs) — nice touch, 1-2 small boxes.\n\nEncoder covers: small round caps on one side of each joint (cylinder r smaller, dark) — believable.\n\nNow assembly pieces per joint (concrete):\n\nBASE (J0/J1):\n- base_plate: rounded box 0.17×0.17×0.014 at z 0.007; dark gray anodized; 4 corner bolts (hex r 0.004).\n- base_lower: cylinder r=0.062 depth 0.03 z=0.014+0.015 → center 0.029? plate top at 0.014; cyl from 0.014 to 0.046.\n- bearing ring: r=0.056 depth 0.012 z 0.046..0.058 dark steel + orange thin ring accent at seam (r 0.0565 depth 0.002).\n- turret: r=0.05 depth 0.035 z 0.058..0.093.\n- turret top plate: r=0.055 depth 0.008 z 0.093..0.101 with 6 bolts on its top face circle r=0.044.\n- shoulder cheeks: two rounded boxes 0.05(x)×0.012(y)×0.075(z) centered x=0? The shoulder axis at z_sh = 0.165. Cheeks from z 0.10 to 0.18 at y=±0.043. Actually cheek plates bolt onto turret top. Cheek box dims: x 0.055, y 0.014, z 0.08, center (0, ±0.043, 0.14). Bearing caps: cylinders axis Y at y=±(0.043+0.007..+0.02): outer cap r=0.03 depth 0.012 centered y=±0.056, z=0.165. Hinge pin: cylinder r=0.011 axis Y spanning y -0.062..0.062 at z=0.165. End nuts: hex at y=±0.065.\n- motor for J2: cylinder r=0.024 depth 0.05 axis Y mounted behind? Place on -Y side: housing r=0.026 from y=-0.056 to -0.106 (depth 0.05) centered y=-0.081 z=0.165, with end cap + cable stub from cap going down into turret (curve). \n\nLink1 root hub attached between cheeks: hub cylinder axis along link1 dir at start point A1 = (0,0,0.165) extending toward elbow: hub from t=-0.02 to 0.035 along u1. Hub r=0.026. Cross pin through hub & cheeks is the J2 pin (same axis z=0.165). Good: hub center at A1.\n\nCompute A1 = S = (0, 0, 0.165). a1 = 48° from vertical (toward +X). u1 = (sin48, 0, cos48) = (0.7431, 0, 0.6691). L1 = 0.30. Elbow E = S + 0.30*u1 = (0.2229, 0, 0.3657).\n\nChoose wrist W: want reach: a2 such that forearm goes down-forward. W = (0.435, 0, 0.150). vec EW = (0.2121, -0.2157), len = 0.3024 → set L2 = 0.3024 exact (compute in code). u2 = normalize.\n\nWrist joint at W: wrist pitch axis Y. Tool direction: aim at object. Gripper assembly: from W, tool mount extends along u3. Let object top point target G = W + u3 * 0.11 where u3 = rotate u2 further downward by angle β = 25° (more vertical). u2 angle from horizontal: atan2(-0.2157, 0.2121) → -45.5°. u3 = -70.5° from horizontal (pointing down steeply). Fingertips at W + u3*0.115: = (0.435+0.0384, 0, 0.150-0.1084) = (0.4734, 0, 0.0416). Object on desk top z: object height ~0.028 → top z=0.028, center (0.4734+ small x?, 0). Fingertips at z 0.042 hovering just above object top (0.028): gap 0.014 — fingers on either side (Y ±0.014) poised to grab. Looks mid-reach, about to grasp. Object center x = fingertips x + 0.005 = 0.478. Good.\n\nELBOW (J3): axis Y at E. Link1 end hub at E (cylinder along u1 r=0.022 depth 0.05 centered at E - u1*0.01). Cheeks of link2 root: two plates y=±0.032 around E, extending along u2 0.05. Bearing caps axis Y r=0.022 at y=±0.038, pin r=0.008. Motor on +Y side: r=0.02 depth 0.045 centered y=0.06. Encoder cap on -Y: r=0.016 depth 0.008 dark.\n\nHub2 (link2 root between cheeks): cylinder axis u2 r=0.02 from E-0.01 to E+0.03.\n\nLink2 strut from E + u2*0.025 to W - u2*0.03 (hub lengths), depth 0.05→0.032, radii 0.0075→0.0055.\n\nWRIST (J4) at W: small housing axis Y: cheeks from link2 end? Make wrist: link2 end hub r=0.016 axis u2; wrist block: cylinder axis Y r=0.018 depth 0.05 (y -0.025..0.025) at W — the rotating part attaches tool. Bearing caps r=0.014 y=±0.027. Small motor r=0.014 depth 0.03 on +Y at y=0.038. Pin r=0.006.\n\nWRIST ROLL (J5): from W along u3: actuator cylinder r=0.016 depth 0.038 centered W+u3*0.019 (axis u3) — housing attached to wrist block rotates around u3. Accent ring. Tool flange disc r=0.02 depth 0.006 at W+u3*0.042 with 4 bolts.\n\nGRIPPER at GP = W + u3*0.048: body box 0.036 (along u3) × 0.042 (y) × 0.026 (w3) — need orientation frame: u3 tool axis, v=Y lateral, w3 = cross(u3, v). Body rounded box bevel 0.004. \n- Top servo: small cylinder r=0.009 depth 0.02 along w3 on top? place on -w3 side (top relative world up?) w3 = cross(u3, v): u3 ≈ (0.334, 0, -0.943); cross(u3,(0,1,0)) = (u3.y*0 - u3.z*1, u3.z*0 - u3.x*0, u3.x*1 - u3.y*0) = (0.943, 0, 0.334). That points up-forward (+x,+z). So w3 is the \"top\" side of tool. Servo on top at GP + w3*0.018: cylinder axis w3 r=0.0085 depth 0.016. Cable from servo to wrist motor along body (short curve).\n- Finger rails: two parallel rods axis v (Y) spanning body front? For parallel gripper, fingers slide along Y. Rods: cylinders r=0.003 axis Y length 0.05 at GP + u3*0.012 ± w3*0.008, ends held by body end plates: two small plates at y=±0.021 (boxes 0.03×0.004×0.02).\n- Fingers: carriages: boxes 0.014×0.008×0.018 at y=±0.014, positioned GP + u3*0.012. Finger plates extend +u3: from carriage, plate dims: length 0.05 along u3, thickness 0.0045 in Y, height 0.014 in w3 → box centered at GP + u3*0.037 + y=±0.014. Tips: pads on inner faces (y facing center): pad box 0.012×0.004×0.012 at GP + u3*0.058, y=±0.0115, orange urethane. Also small pivot pins on carriage (visible pivots): cylinders r=0.003 axis w3? Add pin through finger root: cylinder axis w3 r=0.0028 at carriage with end caps — suggests linkage. Plus tiny linkage rod from servo wedge to finger: thin cylinder connecting servo bottom to finger mid — adds believability; two rods.\n- Gripper open gap: pads inner faces at y=±0.0095; object max radius 0.012?? Object puck r=0.018 → fingers wouldn't close around but mid-reach open pose is fine: gap 0.019 vs object head r=0.012 (hex top across ~0.024?) Keep object top shaft r=0.009 → fits gap. Pads hover beside object head? Pads at z around fingertip z 0.042; object head at z 0.02..0.028 — pads slightly above. Adjust: fingers a bit lower or object taller: make object total height 0.036 (like a small knob), head z 0.028..0.036, pads at z ~0.038..0.05 hovering just above head, fingers beside head region at y ±0.011 vs head r 0.009: gap 2mm each side. Believable \"about to grab\". Good enough; slight mismatch ok since mid-reach.\n\nNumbers computed at runtime — I'll compute G target then place object. To be safe about desk intersection: lowest fingertip z = 0.0416 - pad half height (0.006) ≈ 0.035 > 0. OK.\n\nBolts everywhere: flange bolt circles: base top plate 6 bolts; hub flanges 4 bolts each; gripper flange 4 bolts; cheek caps 4 small bolts each. Helper `bolt_ring(center, axis, ring_r, n, r_bolt, depth)`.\n\nAlso add subtle panel lines? skip.\n\nDesk props: controller box at (-0.16, 0.14, z on desk) with LED; cable from box to base rear (curve on desk surface). Also maybe a slim monitor arm? Too much. Add small nameplate on base? skip.\n\nExtra small part: a tiny bearing near object: torus r=0.008 + inner ring, lying flat at (0.40, 0.10). And maybe two M3 washers. Keep 1-2.\n\nGround/floor: big plane 30x30 at z=-0.78, light gray, rough 0.6. Desk legs: 2 panel legs 0.05 thick: boxes 0.7(y)×0.04(x)×0.72 at x = 0.0? Desk slab: center (0.15, 0, -0.036), dims 1.5×0.9×0.045 → top z=-0.0135?? Set slab top at z=0: center z = -0.0225. Legs under: at x=-0.45 and x=0.75? Desk x range 0.15±0.75 → -0.6..0.9. Legs at x=-0.5, 0.8, y=0, panel dims (0.05 x, 0.8 y, 0.755 z) center z = -0.045-0.3775 = -0.4225 → from -0.045 to -0.8. Floor at -0.80. Legs bevel 0.008. Desk bevel 0.012.\n\nHmm wait: is base at x=0 with object at 0.478 — desk extends to 0.9, fine. Controller at x=-0.2? within desk. Fine.\n\nBackdrop: since orbit renders around, a clean floor + world suffices. Add a subtle large softbox card? The area lights themselves. Maybe add a big vertical gradient backdrop plane behind (y=+1.6) light gray — from other orbit angles it'd float. Skip; keep floor + world. World color: use nodes with Background color (0.055 gray) strength? For studio look, world slightly bright: color 0.8 gray at strength 0.35 gives soft ambient + gray horizon. In render, background will be mid-gray — premium with rim lights. Maybe use a gradient world? Keep simple gray.\n\nColor management: AgX (default in 5.x) with look 'AgX - Medium High Contrast'? Set `scene.view_settings.look = 'AgX - Medium High Contrast'`? In 5.1 look options: 'AgX - Medium High Contrast' exists (Blender 4.x). 5.1: might be renamed... Safer: set display_settings? I'll try setting look in try/except.\n\nCamera: compute target (0.22, 0.02, 0.20). Camera pos: from front-right? Arm extends +X; nice view from (0.95, -1.05, 0.55) — 3/4 front-left? Y negative is front. Distance ~1.5. Lens 58mm? With square frame 1536, sensor 36mm: FOV ~ 2*atan(18/58)=34.4°. Arm bounding ~0.75 wide, 0.5 tall. Distance 1.5 at 34° covers ~0.92 wide — ok with margin. Let's place camera (1.05, -1.25, 0.62), lens 60, target (0.20, 0, 0.19). Check vertical: target z 0.19 mid of arm height 0..0.48? Base bottom 0, top elbow 0.366 + caps ~0.39; desk front edge at z -0.045 visible bottom. Should fit.\n\nI'll add a slight depth of field: f-stop 5.6 focus on elbow/gripper mid (focus object empty at (0.35,0,0.15))? DOF adds premium look; but benchmark 360 orbit uses same camera only for presentation; orbit likely overrides camera anyway. DOF at f/5.6 mild. Use focus_empty at gripper (0.44,0,0.12), fstop 6. Background slightly soft. OK.\n\nLights:\n- key: area, size 0.9, energy 900W? Scale: scene ~1m; use energy 700, loc (0.6, -0.9, 1.6), pointing at (0.25,0,0.2). Area light size 0.8 for soft.\n- fill: area size 0.7 energy 350, loc (-1.0, -0.4, 0.9), cool tint (0.85,0.9,1.0), target (0.2,0,0.2).\n- rim/top: area size 0.6 energy 600, loc (0.2, 0.9, 1.5) target elbow — creates top/back edge light.\n- small spot/area on gripper region: area 0.3 energy 150 at (0.9, -0.3, 0.7) aimed at gripper for sparkle? Optional.\nSet light color key slightly warm (1.0, 0.96, 0.9).\n\nUse light_energy units W. At scene scale meters with cycles, 400-1000 typical.\n\nAlso enable contact shadows? Cycles handles.\n\nMesh helpers:\n\n```python\ndef box(name, loc, scale_dims, mat, bevel_w=0.0):\n    bpy.ops.mesh.primitive_cube_add(location=loc)\n    o = bpy.context.active_object; o.name=name\n    o.dimensions = dims\n    bpy.ops.object.transform_apply(location=False, rotation=False, scale=True)\n    if bevel_w>0: add bevel mod apply\n    assign mat\n```\n\nOrientation for boxes: pass rotation too (e.g., finger plates aligned to u3: rotation about Y by angle). Use quaternion from basis: build matrix from (u3, v, w3) columns. Helper `orient_obj(obj, x_axis, y_axis, z_axis)` set matrix_world rotation from Matrix((x,y,z)).transposed() → 4x4 with translation.\n\nCylinders aligned: `cyl(name, r, depth, loc, axis=None, verts=48, mat, bevel)`: create with rotation quaternion if axis given.\n\nBevel modifier application: \n```python\ndef bevel(obj, w, seg=3):\n    m = obj.modifiers.new('bev','BEVEL'); m.width=w; m.segments=seg\n    bpy.context.view_layer.objects.active = obj\n    bpy.ops.object.modifier_apply(modifier=m.name)\n```\nApplying many modifiers headless is fine but slower; scene moderate (~150 objs). OK.\n\nFor smooth shading cylinders: after bevel, set polygons smooth. But end cap n-gons smooth cause shading artifacts; with bevel + smooth by angle better: use `obj.data.set_sharp_from_angle`? In 5.x, use modifier \"NODES\"? Simpler: keep flat shading for small parts; for larger visible housings, smooth + bevel gives decent look; caps may show minor artifacts — mitigate by using bevel segments 3 and setting `m.limit_method='ANGLE'` and shading smooth with autosmooth via geometry nodes? There's `bpy.ops.object.shade_smooth_by_angle()` in 4.1+ (operator). In 5.1: `bpy.ops.object.shade_smooth(use_auto_smooth?)`? The operator `shade_smooth_by_angle` exists in 4.1+? I recall `bpy.ops.object.shade_smooth_by_angle()` added in 4.1. Hmm risky. Alternative: mesh.set_sharp_from_angle is a Mesh method (`mesh.set_sharp_from_angle(angle=...)`) added 4.1? There's `bpy.ops.mesh.customdata_custom_splitnormals_clear`... \n\nSimplest robust: for cylinders, after creation with `bpy.ops.mesh.primitive_cylinder_add`, do: for polys: use_smooth = (len(p.vertices)==4)? side quads are 4-verts; caps are n-gons (len>4) → smooth only side faces; caps stay flat → clean look without auto smooth. With bevel modifier applied, bevel faces are quads too (smooth ok). Do this: `for p in me.polygons: p.use_smooth = len(p.vertices) <= 4`. Bevel creates quads & maybe n-gon remnants? After bevel on cylinder, caps become n-gon rings still n-gons. Works.\n\nFor boxes bevelled: flat faces n-gons/6+? bevelled cube: original faces become smaller quads? Original cube faces become n-gon with holes? No — bevel turns each face into a smaller quad-ish n-gon (still 4 corners but with chamfer corners: face becomes octagon? Actually bevel on cube: each original face becomes a smaller square (4 verts), corners become triangles/quads, edges become quads. With `segments=3`, corner patches. All faces small; smooth shading all with angle limit? Use `m.limit_method='ANGLE'` and shade all smooth + `harden_normals=True`? Without weighted normals, smoothing on box looks puffy. Keep boxes flat-shaded with bevel — crisp machined look; bevel highlights still appear (flat faces + bevel facets = fine, slight faceting on 3-seg bevel acceptable; use segments=2 flat? facet lines visible at grazing. Acceptable).\n\nActually nicer: after bevel on boxes, set bevel `segments=3`, and shade smooth only faces with normal similar... overkill. Flat shading fine for product look with small bevels.\n\nStrut skin+subsurf: shade smooth all.\n\nMembrane: smooth.\n\nCurve cables: smooth by nature.\n\nGLB export: The harness exports GLB itself? \"an interactive 3D scene exported to GLB\" — the benchmark handles export from saved scene; my script should just build scene + save .blend? The harness runs the script then does capture/export. The instructions: \"save a complete scene\". I should call `bpy.ops.wm.save_as_mainfile(filepath=...)`? Harness probably saves after script, or expects script to save? \"Make the important requirements evident in the published result, save a complete scene\" — I'll save to a path like `/tmp/robot_arm.blend`? Risky unknown env; maybe harness saves automatically. Hmm. Typical Blender-Bench harness: script runs, then harness saves scene & renders. To be safe, save mainfile to a sensible path derived from `bpy.path.abspath(\"//\")`? If unsaved blend, `//` = cwd. I'll do `bpy.ops.wm.save_as_mainfile(filepath=bpy.path.abspath(\"//robot_arm_scene.blend\"))` wrapped in try/except so it can't crash the run. Also set render settings (engine CYCLES, resolution 1536, samples 64, denoise on) as good defaults; benchmark overrides anyway.\n\nAlso set camera as scene camera, set unit scale metric.\n\nRender settings: engine 'BLENDER_EEVEE_NEXT' vs CYCLES: set CYCLES; if no GPU headless, fine, they override. Set samples 64, use_denoising True, resolution 1536x1536, film transparent False.\n\nSet world background: nodes, color (0.06?) Let me choose world strength 0.4, color (0.75,0.75,0.78)*? That yields gray ~0.3 in AgX. Nice.\n\nGround plane material: Principled base (0.82,0.81,0.79), roughness 0.55. Desk: (0.72,0.70,0.67) rough 0.45? Or white laminate (0.85). Desk slightly darker than floor for separation. Add subtle desk edge chamfer.\n\nNow write the strut function carefully:\n\n```python\ndef optimized_strut(name, A, B, dA, dB, rA, rB, v_axis, n=10, bend=0.012, x_bays=(4,), membrane_bays=(2,3,6), hub_embed=0.0):\n    A=Vector(A); B=Vector(B)\n    u=(B-A); L=u.length; u.normalize()\n    v=Vector(v_axis).normalized()  # lateral\n    w=u.cross(v).normalized()\n    v=w.cross(u).normalized()  # orthogonalize\n    prof=lambda t: 0.6+0.55*abs(math.cos(math.pi*t))**0.75\n    def rad(t): base=rA+(rB-rA)*t; return base*(1.28-0.5*math.sin(math.pi*t))\n    verts=[]; \n    tops=[]; bots=[]\n    for i in range(n+1):\n        t=i/n\n        C = A + u*(L*t) + w*(bend*math.sin(math.pi*t))\n        h = (dA+(dB-dA)*t)/2*prof(t)\n        T = C + w*h; D = C - w*h\n        tops.append(len(verts)); verts.append(T)\n        bots.append(len(verts)); verts.append(D)\n    edges=[]\n    for i in range(n):\n        edges.append((tops[i],tops[i+1])); edges.append((bots[i],bots[i+1]))\n    edges.append((tops[0],bots[0])); edges.append((tops[n],bots[n]))\n    for i in range(n):\n        if i%2==0: edges.append((tops[i],bots[i+1]))\n        else: edges.append((bots[i],tops[i+1]))\n    # extra X at middle bay\n    mid=n//2\n    edges.append((tops[mid], bots[mid+1])); edges.append((bots[mid], tops[mid+1]))\n```\n\nWait — zigzag already covers each bay with one diagonal; adding the second diagonal on the middle bay makes an X there. Ensure not duplicate edge: zigzag for bay i adds one of the two diagonals depending parity; adding both for mid bay — one may duplicate existing edge → duplicate edges in mesh from_pydata cause error? Duplicates get merged? from_pydata may create invalid geometry with duplicate edges — safer: compute set of diagonal keys, then ensure both diagonals of mid bay included:\n\n```python\ndiag=set()\nfor i in range(n):\n    if i%2==0: diag.add((tops[i],bots[i+1]))\n    else: diag.add((bots[i],tops[i+1]))\ndef key(a,b): return (min(a,b),max(a,b))\ndiag.add((tops[mid],bots[mid+1])); diag.add((bots[mid],tops[mid+1]))\nedges += [tuple(e) for e in {key(*e) for e in diag}]\n```\n\nAlso maybe add small mid-node knuckles? skip.\n\nRadii per vertex: for i,t: rt = rad(t); assign both top/bottom nodes radius (rt*1.15 for swollen nodes?). Skin radius units are absolute scale factors relative to object scale (radius multiplies by... skin radius default (0.25,0.25) relative in object units: actual radius = skin radius value in object local units). So set radius = (rt, rt).\n\nBranch swelling: at nodes where diagonals meet, skin naturally bulges.\n\nMesh create:\n```python\nme=bpy.data.meshes.new(name)\nme.from_pydata([v[:] for v in verts], edges, [])\nob=bpy.data.objects.new(name, me); collection.link(ob)\nsk=ob.modifiers.new('skin','SKIN')\nsv=me.skin_vertices[0].data\nfor i,d in enumerate(sv): d.radius=(radii[i],radii[i])\nsv[0].use_root=True\nsub=ob.modifiers.new('sub','SUBSURF'); sub.levels=2; sub.render_levels=2\nsmooth polys\n```\n\nNote: skin_vertices layer appears only after modifier added — order: create mesh w/o skin data; add modifier; then access me.skin_vertices. I believe adding Skin modifier creates the data layer. Yes (this is the standard scripting pattern).\n\nSubsurf on skin result: skin output is quads — good.\n\nMembrane panel for bay i (between node i and i+1): corners T_i, T_{i+1}, D_{i+1}, D_i. Inset factor 0.1 toward centroid. Build grid 6x6: point(s,r) bilinear interpolation of inset corners + normal offset bow*4*s*(1-s)*r*(1-r)... normal = v (lateral) — but which side? Film spans the bay like a window: lies in the u-w plane; normal = ±v. Bow outward +v*0.0025? On a planar beam, film covers one face (+v) — but then the other face (-v) open. Could add both faces for select bays (sandwich) — \"panels spanning openings within the struts\". A panel across the opening (in plane of rails) reads as covering the hole like a drum on each side, or a single mid-plane membrane inside. I'll place panels at mid-plane (the v=0 plane, since bay lies in plane through v=0 anyway — rails are at ±w, so bay plane is the strut mid-plane). A film stretched across the opening in the mid-plane with slight bow — reveals both sides, structure (rails+diagonal) borders it. \n\nPanel grid:\n```python\ndef quad_panel(name, P00,P10,P11,P01, normal, mat, bow=0.003, nx=8, ny=8, thick=0.0012):\n    verts=[]; faces=[]\n    for j in range(ny+1):\n        s=j/ny\n        for i in range(nx+1):\n            r=i/nx\n            top=P00.lerp(P10,r); bot=P01.lerp(P11,r)?? careful mapping\n```\nLet P00=D_i? corners order: c00=bottom_i? Let's define A_=T_i,B_=T_{i+1},C_=D_{i+1},D_=D_i. Bilinear: p = (1-r)(1-s)A + r(1-s)B + r s C + (1-r)s D. Bow: + normal*bow*sin(pi r)*sin(pi s). Inset: first inset corners toward centroid by 12%.\n\nSolidify modifier thickness 0.0011, offset 0. Subsurf level 2 on grid? grid 8x8 dense enough; add Subsurf 1 for silk smooth? 9x9 verts with sin bow already smooth. Skip subsurf; shade smooth; solidify (with even thickness). Solidify on grid w/o rim issues fine.\n\nAlso membrane needs to visually \"attach\": inset leaves gap to rails — floating? Inset 0.06 small gap; at render distance fine, plus could add tiny edge frame: skip, small inset (0.05) reads as bonded film. Actually overlapping rails slightly better (no gap): inset 0.0 → film edges under rails; rails radius ~0.008-0.01 cover the seam. Use inset 0.02 and bow 0.003.\n\nMembrane material: Principled BSDF: base_color (0.75, 0.82, 0.88), roughness 0.32, metallic 0.0, transmission weight 0.9, IOR 1.38, alpha 1. Also `coat` 0.2? Fine. In Cycles, thin transmission shows structure behind. Slight blue-gray tint. Maybe add subtle procedural bump via Noise→bump for mesh texture (\"fine architectural mesh\")? Procedural noise bump scale 300 detail 2 strength 0.15 — fine mesh feel. GLB bakes maybe; ok.\n\nActually careful: transmission 0.9 with roughness 0.32 may look like glass; TPU film ≈ glass-like — good. Tint slightly warm-smoke (0.8,0.83,0.85).\n\nCables helper:\n\n```python\ndef cable(name, points, radius, mat):\n    cu=bpy.data.curves.new(name,'CURVE'); cu.dimensions='3D'\n    sp=cu.splines.new('BEZIER'); sp.bezier_points.add(len(points)-1)\n    for bp,co in zip(sp.bezier_points, points):\n        bp.co=co; bp.handle_left_type='AUTO'; bp.handle_right_type='AUTO'\n    cu.bevel_depth=radius; cu.bevel_resolution=3; resolution\n    ob=...\n```\n\nCable paths:\n1. Base→turret internal: tiny loop from turret back to base top — points around J1? Represent as short cable from motor cap (J2 motor rear) down to turret top port: pts from motor end (y=-0.108,z=0.165) curving to (−0.03, −0.05, 0.105). \n2. Link1 cable: from turret top port (x=-0.02,y=-0.03,z=0.105) to elbow motor (E + (0,0.045,0)): route along inner side of link1: offset = -w*0.045 - v*0.02 from centerline at t=0.15,0.5,0.85 plus endpoints. With AUTO handles gives smooth hug.\nHmm keep cables on the -Y side (back from camera?) Camera at -Y: front is -Y side. Cables visible = good detail; place along -Y side slightly, neat. Clips: small boxes at t=0.3,0.6 positions.\n3. Link2 cable: elbow motor top → wrist motor: similar along link2 inner side (-w2).\n4. Servo cable wrist→gripper: short along tool body.\n5. Controller box → base: desk-level curve from box front to base plate rear... base at origin; box at (-0.18, 0.16): path along desk: [(-0.13,0.14,0.012),(-0.06,0.10,0.006),(-0.02,0.05,0.004),(0,0.03,0.008)] into base side port at (0,0.045,0.02)? Base r=0.062; port at y=+0.05? Let controller be at (-0.18,-0.16) front-left? Camera front -Y: controller front-left visible. Path neat S-curve.\n\nKeep total cables modest.\n\nSmall clips: torus clips around strut rails? Simplify: clip = small box on inner rail node position holding cable: place at t positions, box dims (0.012,0.014,0.008) oriented to u/v/w. 2 clips per link.\n\nStatus LEDs: tiny emissive cylinders (r 0.0025 depth 0.002) on elbow cap, wrist, turret front, gripper body. Green (0.1,1,0.3) emission strength 4. On -Y faces (camera side).\n\nBolts: hex heads: cylinder verts=6 radius r, depth; plus shaft? just head + washer face. Bolt ring helper creates n bolts on face plane given center, axis, ring radius: each bolt axis = axis. Hex orientation random rotate for realism (align same).\n\nMaterials list:\n- mat_titanium (struts): (0.62,0.63,0.65) metallic 1.0 rough 0.34\n- mat_alu (housings): (0.75,0.76,0.78) metallic 1.0 rough 0.22\n- mat_alu_dark: (0.16,0.17,0.19) metallic 0.95 rough 0.3 (anodized dark)\n- mat_steel (pins/bolts): (0.45,0.46,0.48) metallic 1 rough 0.18\n- mat_accent (orange anodized): (0.85,0.30,0.05) metallic 0.9 rough 0.28\n- mat_pad (urethane amber): (0.9,0.45,0.08)? pads maybe dark rubber (0.06,0.06,0.06) rough 0.7; choose amber urethane translucent-ish: base (0.85,0.4,0.05) rough 0.5 — reads replaceable pad.\n- mat_cable: (0.012) rough 0.55\n- mat_membrane as above\n- mat_desk: (0.80,0.79,0.76) rough 0.4\n- mat_floor: (0.55,0.55,0.56)? Floor slightly darker gray than desk for contrast; rough 0.5.\n- mat_object: machined aluminum + accent ring\n- mat_box (controller): dark (0.05,0.05,0.06) rough 0.4 metallic 0.2\n- mat_led_green emission\n\nWorld: nodes Background strength 0.5 color (0.6,0.62,0.66)? Grayish cool. Hmm with AgX, 0.6*0.5=0.3 → mid gray. Good.\n\nAlso add a big soft gradient? skip.\n\nExtra realism: joint stop tab on shoulder: small box on cheek inner + on link1 hub? skip—minor.\n\nNaming all objects nicely.\n\nObject count moderate. Let's also add subtle screw heads on desk base plate corners: 4 hex bolts at (±0.07,±0.07) on plate.\n\nGripper rails plates etc. — ensure no intersection with object: fingertips around (0.473,±0.014,0.042) vs object at (0.478,0) head r 0.009 z up to 0.036: finger plates inner faces at y=±(0.014-0.00225)=±0.01175 → gap to head surface (r0.009→ y extent ±0.009) = 2.75mm. \n\nWait: also check finger plate height in w3: 0.014 centered at GP+u3*0.037 — plates extend along u3 from GP+u3*0.012+... let me define finger plate: start at s=0.014 (from GP along u3) end s=0.062; center s=0.038; length 0.048. Pad at s=0.056..0.066? pad length 0.012 centered s=0.060: pad world pos = GP + u3*0.060 ± ... pad height (w3) 0.012, thickness Y 0.004 inner at y=±0.010 → inner faces at ±0.008 — hmm pads closer to center than plates? For parallel gripper pads inner faces at y=±0.0105 (pad thickness 0.003): gap between pads 0.021 > object head diameter 0.018 → 1.5mm/side. ok.\n\nPad world z: GP = W + u3*0.048 = (0.435+0.0160, 0, 0.150-0.0452)=(0.451,0,0.1048). Pad center = GP + u3*0.060 = (0.451+0.0200,0,0.1048-0.0566)=(0.471,0,0.0482). Pad height 0.012 along w3 (mostly vertical) → z 0.0422..0.0542. Object head top 0.036. So pads hover ~6mm above head — reads as approaching/aligning before descent. Acceptable mid-reach. Could lower wrist: reduce W z to 0.135 & aim steeper: u3 angle -78°: fingertips z ≈ 0.135-0.117=0.018 too low maybe collide pads with desk? pad bottom 0.018-0.006=0.012 ok... Let me keep some clearance: W=(0.435,0,0.145), u3 = u2 rotated -30°. I'll compute in code and clamp object under fingertips: object at fingertips + u3*0.025 projected to desk (x,y), z on desk. Then visual gap = distance from pads to object top along -u3... object height 0.036. Choose numbers to make pads ~8-12mm above object top — \"poised\". Fine.\n\nSimpler: I'll compute F = W + u3*0.115 (fingertip s=0.115? earlier 0.11). Then object_center_xy = (F + u3*0.02) with z=0 projection: obj_x = F.x + u3.x*0.02, obj_y = 0. Place object there. Good.\n\nDouble-check elbow/wrist angles plausible (< 150°): fine.\n\nAlso J1 rotation: arm oriented toward +X; turret rotates about Z — show slight rotation? Keep 0 (facing +X), camera at -Y sees side profile... 3/4 view better: rotate whole arm assembly about Z by -12°? Instead put camera at (1.05,-1.15,0.6) → sees front-right? +X is right side of frame when viewed from -Y. Camera at y=-1.15, x=1.05 looks toward origin: sees arm from front-right 3/4. Object at x≈0.47 closer to camera (x 0.47 vs base 0) — good depth. Gripper pads gap visible from this angle? Pads separate along Y; camera mostly along -Y → sees one finger behind other... Camera direction from (1.05,-1.15,0.62) to (0.2,0,0.2): d=(-0.85,1.15,-0.42) — significant Y component → sees XZ plane mostly; finger separation along Y appears as depth offset — partially visible. To show two fingers clearly, camera should have more side angle (along ±X? fingers separate along Y, tool axis in XZ plane; viewing along tool axis shows gap). A 3/4 from front-right shows fingers slightly. Also GLB orbit shows all. Add slight Y offset to camera target and keep camera x moderate: cam (0.95,-1.35,0.62), target (0.22,0,0.18). Fine.\n\nActually, maybe rotate entire robot about Z by +18° so the reach direction points slightly toward camera-left? Hmm keep axis-aligned for cleanliness; camera 3/4 handles depth.\n\nNow, membrane normal: ±v (Y). Film in mid-plane: bow along v*0.003.\n\nLet me also double-check skin modifier radius interplay with subsurf: typical pattern works.\n\nOne more requirement: \"recessed cable guides\" — the clips serve. Also maybe a spiral conduit on J1? skip.\n\nEnd effector actuation: add tiny linkage rods: from servo bottom (GP + w3*0.008) to each finger plate mid-top: thin cylinders r=0.0018 — with fingers at ±y the rods would angle — draw from servo to y=±0.014 plate tops. Compute rod endpoints: P1 = GP + u3*0.010 + w3*0.014 (servo tip), P2a = GP + u3*0.030 + w3*0.009 + v*0.014, P2b mirrored. Cylinder between points helper `rod_between(p1,p2,r,mat)`.\n\nAlso add visible pivot pins on fingers: at s=0.020 through carriage axis w3 r=0.003 length across 0.02 with cap discs.\n\nAlso gripper body: end plates at y=±0.022 holding rails: boxes (0.024 x? ) oriented frame: dims along (u3,v,w3) = (0.026, 0.004, 0.020) at GP+u3*0.012 ±v*0.022.\n\nRails: rods axis v from y=-0.022..0.022 at s=0.012, w3 offsets ±0.0065.\n\nCarriages: boxes dims (0.012,0.010,0.016) at s=0.012, y=±0.014.\n\nFingers plates: dims (0.048,0.0045,0.013) center s=0.038, y=±0.014, plus a 45° taper? keep straight with bevel 0.002.\n\nPads: dims (0.012,0.003,0.011) center s=0.058, inner y=±(0.014-0.00225+0.0015)= attach to plate inner face: plate inner face y=±(0.014-0.00225)=±0.01175; pad center y=±(0.01175-0.0015)=±0.01025. Pad slightly proud inward. Also pad face grooved? skip.\n\nWait fingers should extend from carriages at s~0.012 forward; root overlaps carriage: plate starts s=0.014 ends 0.062 — pad at s 0.052..0.064 beyond plate end? pad center s=0.058 length 0.012 → 0.052..0.064; plate ends 0.062. Fine.\n\nAlso small stop block between carriages? skip.\n\nGripper total from W: flange at s=0.042..0.048 (r0.02 disc), body s=0.048..0.048+0.036? Body center GP at s=0.048+? Let body span s 0.046..0.082: center s=0.064, dims u3 0.036. Redefine GP_body = W + u3*0.064. End plates at s=0.078? Rails at s=0.076 (front portion) spanning y; carriages at s=0.076; fingers from s=0.078 to 0.126; pads center s=0.122. Fingertip s≈0.128. W to tips = 0.128.\n\nHmm earlier I planned tips at 0.115; recompute: W=(0.435,0,0.145), u3 = rotate u2 down by extra angle. Let me just compute in code: choose wrist W, compute u2=(W-E)/|.|; u3 = rotate u2 about Y by -δ (δ=28° more downward). F = W + u3*0.128. Ensure F.z ≈ 0.035-0.045. u2 angle θ2 = atan2(u2.z, u2.x). With E=(0.2229,0,0.3657) W=(0.435,0,0.145): Δ=(0.2121,-0.2207), θ2=-46.1°, L2=0.3061. u3 angle = -74.1°: u3=(0.2735,0,-0.9619). F = W + 0.128*u3 = (0.435+0.0350, 0, 0.145-0.1231) = (0.4700, 0, 0.0219). Pad center s=0.122: z = 0.145-0.1173=0.0277; pad bottom ≈ 0.0277-0.0055=0.022. Object height must be < 0.02 to fit under pads?? Then object too short. Reduce reach: tips should hover ~0.045: choose W=(0.425,0,0.165): Δ from E=(0.2021,-0.2007) θ2=-44.8° L2=0.2848. u3 angle -72.8° (δ=28°): u3=(0.2956,0,-0.9553). F=W+0.128u3=(0.4628,0,0.0427). Pads z center=0.165-0.1166=0.0484, bottom ~0.043. Object: place under F + u3*0.02 → x=0.4687, top of object ~0.036 (height 0.036) → gap pads-to-top ≈ 0.043-0.036=0.007. \n\nObject: base puck r0.02 h0.006 (z0..0.006), neck r0.012 h0.014 (0.006..0.020), head: rounded knob r0.013 h0.016 (0.020..0.036) with torus ring accent at z0.028, hex top? Make it a \"machined demo part\": like a chess-pawn-ish precision weight: stepped. Top: small hex socket recess? skip recess. Head widest r 0.013 → y extent ±0.013 > pads gap (inner faces at ±0.01025)! Pads would clip head if closing, but they're 7mm above it — no intersection since pads z 0.043..0.054 vs head top 0.036. OK visually \"about to grasp the head\". But plates at y ±0.014 with plate z range: plate center s=0.102 → z=0.165-0.0975=0.0675, plates from s=0.078..0.126 → z from 0.0905 to 0.0446. Plates beside object head: head top 0.036 < plate bottom 0.0446 — no overlap. Good, zero intersections.\n\nThen fingers hover 8mm above object — mid-reach ✓.\n\nObject also add knurl? Add thin torus grooves ×2 on head. Fine.\n\nLet me now also design turret/cheek geometry to avoid intersection with link1 at 48°: cheeks at y=±0.043, plate dims x0.06 z from 0.10..0.19: link1 hub r0.026 at A1=(0,0,0.165) between cheeks (gap y ±0.036..? cheeks inner faces at y=±(0.043-0.007)=±0.036; hub depth along v? hub is cylinder along u1 with r 0.026 — its circular section passes between cheeks ✓ (0.026<0.036).\n\nBase cabling: cable1 from J2 motor rear cap (y=-0.106? motor on -Y side) down into turret top at (-0.03,-0.03,0.105): points: [(0,-0.112,0.165),(0.0,-0.10,0.13),(-0.01,-0.06,0.108),(-0.02,-0.03,0.104)]. Hmm motor cap at y=-0.106 centered x0 z0.165. Port on turret top: small cylinder at (-0.025,-0.03,0.10) r0.006. OK.\n\nLink1 cable: start at turret top port2 (0.02,-0.035,0.105)? route along -v side (front? v=Y; camera -Y so -Y side faces camera: cables visible → good \"controlled routing\" showcase). Actually camera sees -Y faces; put cables at y ≈ -0.03..-0.045 hugging inner underside of link1: offset -w1*0.05? w1 = u1 × v → u1=(0.743,0,0.669); v=(0,1,0); w1=u1×v = (0*0-0.669*1, 0.669*0-0.743*0, 0.743*1-0*0) = (-0.669,0,0.743). w1 points up-back. Inner side (toward desk front, below beam) = -w1 = (0.669,0,-0.743) (down-forward). Cable under beam: positions p(t)=S+u1*(L1*t) - w1*0.055 + v*(-0.028). At t=0.18,0.5,0.82 plus start near turret (S - w1*0.0 + v*(-0.03) z0.11...) and end near elbow motor (E + v*(-0.05) + w? elbow motor on -Y side too: motor center y=-0.06: cable end at E + (0,-0.055,0)+ u? Put end (E + v*(-0.062) - u2*0.0 ) i.e., at motor cap. Motor cap at y=-0.0825 end. Set end point = E + v*(-0.085) - w1*0.0 → but motor at elbow axis: fine (E.x, -0.085, E.z).\n\nClips at t=0.3, 0.62: small dark box straddling cable to beam: center at p(t)+ w1*0.02 dims small oriented frame(u1,v,w1). \n\nLink2 cable: from elbow motor top (E + v*(-0.085) + w? ) hmm same motor continues: start (E + v*(-0.085) + w2*0.01)?? Simply start at elbow encoder cap front (E + v*(-0.045) + w2*0.0) then along link2 underside: q(t)=E+u2*(L2*t) - w2*0.042 + v*(-0.024), t=0.2,0.55,0.85, end at wrist motor (W + v*(-0.038)). w2 = u2×v: u2=(0.709,0,-0.705)?? compute: u2 = Δ/L = (0.7094,0,-0.7048). w2 = u2×v = (u2.y*0 - u2.z*1, ..., u2.x*1) = (0.7048, 0, 0.7094). -w2 = down-back. Cable offset -w2*0.04 (below beam) + v*(-0.024). OK.\n\nWrist→servo cable: from wrist motor cap (W + v*(-0.05)) to servo (GP_body + w3*0.02 + v*(-0.008)): points: [(W+v*(-0.048)+w2*0.0), (W+u3*0.03+v*(-0.03)+w3*0.01), (GP_body + w3*0.016 + v*(-0.01))]. Short.\n\nController cable: controller box at (-0.20,-0.14) top z0.03; cable from box front port (−0.155,−0.11,0.015) to base rear port: base at origin r0.062 — rear from camera = +Y? camera at -Y: rear = +Y (hidden). Visible routing along desk front: path pts: [(-0.16,-0.115,0.014),(-0.10,-0.09,0.006),(-0.05,-0.075,0.005),(-0.02,-0.06,0.006),(0.0,-0.055,0.012)] end into base side at (0,-0.062,0.02)? base cylinder r 0.062 at y=-0.062 → point (0,-0.060,0.02). Slight S-curve, tidy. Port grommet small cylinder at (0,-0.058,0.02) axis Y.\n\nAlso small grommets where cables enter ports: tiny dark cylinders.\n\nController box: rounded box 0.10×0.07×0.032 at (-0.20,-0.14,0.016)+? sitting on desk: center z=0.016. Top: small recess + LED dot green + tiny label plate (0.05×0.02×0.002 alu). Bevel 0.006.\n\nNow base plate bolts at corners (±0.068,±0.068, plate top z0.014): hex bolts r0.0045 h0.005 + washers r0.0065 h0.001.\n\nBearing rings detail: between turret and lower base: orange accent ring torus? Use thin cylinder r0.057 h0.0025 accent at z 0.0585. And dark ring r0.056 h0.01 z0.052.\n\nShoulder bearing caps: cylinder axis Y r0.030 depth0.012 at y=±0.0560? cheek outer face at y=±0.050 (cheek y dim 0.014 centered ±0.043 → outer ±0.050). Cap center y=±0.056 → spans 0.050..0.062. Cap bolts: 4 small hex on cap face ring r0.022. Pin end nuts at y=±0.065: hex r0.009 depth 0.008.\n\nElbow caps r0.022 at y=±(0.032+?) cheeks2 y dim 0.010 centered ±0.030 → outer 0.035; cap center ±0.041 depth0.010. Pin r0.007 nuts ±0.048. Motor2 on -Y: housing r0.020 depth 0.05 center y=-0.060 (spans -0.035..-0.085) + cap r0.021 depth 0.006 at -0.088, LED on cap? LED on cap facing -Y at (E + (0,-0.092,0)). \n\nWrist: housing block axis Y r0.017 depth0.046 center W; caps r0.013 y=±0.026 depth0.008; pin r0.005; motor3 r0.013 depth0.035 center y=-0.0415 (spans -0.024..-0.059) cap at -0.061.\n\nRoll actuator: cylinder axis u3 r0.015 depth 0.034 center s=0.017 (from W) → spans 0..0.034. Collar accent ring at s=0.036 r0.0155 depth0.003. Flange disc r0.019 depth0.006 center s=0.041. Flange bolts 4× r0.0022 on face ring r0.014 at s=0.0445 facing +u3. Gripper body starts s=0.047.\n\nGripper body: center s=0.065 dims (u3:0.036, v:0.040, w3:0.024) bevel0.004 dark alu. Servo: on +w3 face at s=0.058: cylinder axis w3 r0.0085 depth0.018 center offset w3*(0.012+0.009)=0.021 → from body top face 0.012 to 0.030. Servo cap + tiny cable.\n\nRails at s=0.080: rods axis v r0.0028 length 0.048 centers GP80 = W+u3*0.080 ± w3*0.0065. End plates at s=0.080, y=±0.024 dims (0.020,0.004,0.018). Wait rods length 0.048 → y ±0.024 exactly reaching plates ✓. But rods pass through body front? body spans s 0.047..0.083 v ±0.020: rods at s=0.080 inside body region (s<0.083) and |y|>0.020 outside body v-range → rods ends visible, middle hidden inside body. Rods r0.0028 at y±0.024 → just outside body ±0.020 ✓.\n\nCarriages at s=0.080 y=±0.0135 dims (0.014,0.009,0.015) bevel0.002 — carriage slides on rods; rods at y±0.024... carriage at 0.0135 not on rods. Move rods y span smaller: plates at y=±0.018, rods length 0.036 (y±0.018) at w3 offsets ±0.0065, carriages at y=±0.0135 width 0.009 → spans 0.009..0.018 riding rod ends? Rods pass through carriage: carriage v-extent 0.009..0.018, rods at w3 ±0.0065 within carriage w3 extent (±0.0075) ✓. So rods thread carriage. Fingers at y=±0.0135. Pads inner faces: plate thickness v 0.0045 → inner face y=±0.01125; pad center ±0.00975 thickness0.003 → inner faces ±0.00825, gap 0.0165 vs object head r0.013?? gap diameter 0.0165 < head dia 0.026 — pads above head anyway (no collision); but visually \"open gripper wider than object\" reads better: increase finger y to ±0.017: carriages ±0.017 (span 0.0125..0.0215) — body v half 0.020 → carriage edge 0.0215 slightly outside body — fine (slides proud). End plates at y=±0.022, rods length 0.044 (±0.022) thread carriages ✓. Pads inner faces at ±(0.017-0.00225-0.0015)=±0.01325 → gap 0.0265 ≈ head dia 0.026 — perfect poised-to-close look.\n\nFingers plates: center y=±0.017 dims (0.046,0.0045,0.012) s from 0.084..0.130 (center s=0.107). Pads center s=0.124 dims (0.012,0.003,0.010) y=±0.01525. Fingertips s=0.130. Pad bottom z: W.z + u3.z*0.124 - 0.005 ≈ 0.165-0.1185-0.005=0.0415 ✓ above object top 0.036, gap 5.5mm ✓.\n\nPivot pins: at s=0.090 axis w3 r0.0032 depth across y? Pivot visible on outer face of carriage: cylinder axis v r0.0032 depth 0.011 at y=±0.017 (through carriage) with cap disc r0.0045 at outer y=±0.0217. ✓ \"visible pivots\".\n\nLinkage rods: from servo nose (s=0.058, w3*0.030 → point P1 = W+u3*0.058+w3*0.030, v0) to finger top (s=0.100, y=±0.017, w3*0.008): P2 = W+u3*0.100 + v*(±0.017) + w3*0.008. rod r0.0016 steel. Two rods angled — believable sync linkage.\n\nAlso small gusset plates on gripper body front connecting rails? fine as is.\n\nAlso add wrist tool-side encoder disc: at s=0.0 (W) ring r0.018 dark on block ✓ already housing.\n\nAdd joint rotation axis indicator: thin orange line torus around caps? Accent ring torus around each bearing cap: torus major r=cap_r, minor 0.0012 accent at cap outer face — subtle design language consistency. Add for shoulder, elbow, wrist caps on camera side (-Y) only? Add both sides, cheap.\n\nNow LINK HUBS & flanges:\n- Link1 root hub at A1: cylinder axis u1 r0.026 depth0.055 center A1+u1*0.010 → spans -0.0175..0.0375 along u1 from A1. The J2 pin passes through A1 (z0.165) — hub around A1 ✓. Flange ring r0.030 depth0.006 at A1+u1*0.030? Hub bolts: 4 bolts on a face ring... Strut starts at s0=0.030 from A1 to E-hub. Strut A = A1 + u1*0.032, B = E - u1*0.030. Hub2 at E: cylinder axis u1 r0.022 depth0.05 center E - u1*0.008 (spans E-0.033..E+0.017) r0.022. Elbow cheeks attach to link2 root — wait I set cheeks2 on link2 root around E. Hub for link2 root: cylinder axis u2 r0.020 depth0.055 center E+u2*0.008. Hmm hub1 (link1 end, axis u1) and hub2 (link2 root, axis u2) both near E with pin through E — hub1 spans to E+0.017 overlapping hub2 region... pin axis Y through E; hub1 r0.022 at E along u1, hub2 r0.020 along u2 — they'd intersect each other! Real design: link1 end = fork (clevis), link2 root = single eye between. So: link1 end hub: two cheek plates (fork) on link1: plates axis u1 at y=±0.030, dims (0.05 along u1, 0.010 y, 0.044 w) centered E - u1*0.010 → they wrap around E with pin at E. Link2 root eye: cylinder axis u2 r0.020 depth 0.048? eye center at E: cylinder along u2 centered E + u2*0.012, r 0.019, y-width? The eye needs v-thickness ≤ gap between fork inner faces (±0.025): make eye a flattened cylinder: use box? Use cylinder r0.019 along u2 then scale v 0.9? Simpler: eye = box oriented (u2,v,w2) dims (0.055, 0.036, 0.040) centered E+u2*0.012, bevel 0.010, with bore implied by pin passing through at E. The pin r0.007 through E spans y ±0.048: passes through fork plates (y ±0.030, outer 0.035) and caps at ±0.041. Eye box y ±0.018 between fork inner faces ±0.025 ✓ gap 7mm each side — add thrust washers: cylinders axis Y r0.012 depth0.003 at y=±0.020 centered E ✓ nice detail.\n\nSimilarly shoulder: link1 root hub r0.026 cylinder — but cheeks (fork) are on turret, hub is the eye: hub cylinder along u1 axis, needs v-width ≤ 0.072 (inner faces ±0.036): cylinder depth along u1 not v; its v-extent = r = 0.026 ✓ fine (circular cross-section passes between cheeks with clearance 10mm/side — add thrust washers r0.014 depth0.003 at y=±0.030, z=0.165).\n\nWrist: link2 end hub: cylinder axis u2 r0.016 depth0.045 center W - u2*0.006 → spans W-0.0285..W+0.0165; wrist block r0.017 axis Y at W with pin r0.005 through... link2 end = eye, wrist block = rotating yoke? Make wrist block the eye of link2's fork? Simplify: link2 end has fork plates (y=±0.022, dims (0.04,0.008,0.032) axis u2 centered W - u2*0.008); wrist block (axis Y cylinder r0.016 depth 0.036) sits between, pin r0.005 through W, caps r0.013 at y=±0.028. Thrust washers r0.009 at y=±0.0165. Roll actuator attaches to wrist block front face along u3: cylinder r0.015 from s=0.004.. — block r0.016 → actuator base inside block ✓.\n\nFork plates on link2 end vs hub: replace hub with the two fork plates + cross tube: add cross tube cylinder axis Y r0.013 depth 0.052 at W - u2*0.008 connecting plates (static part of link2) — pin for rotation separate r0.005. OK.\n\nAlso link1 root: add cross tube axis Y r0.020 depth 0.08 at A1 (through hub & cheeks) — the actual hinge pin is r0.011; cross tube = hub sleeve. Skip extra: hub cylinder already there; pin through.\n\nNow strut endpoints:\nLink1 strut: A = A1 + u1*0.034, B = E - u1*0.040 (hub1 region ends E-0.033). dA=0.080, dB=0.056, rA=0.0115, rB=0.0085, n=12, bend along -w1 (outward bulge down-forward): bend sign: use +w1? w1=(-0.669,0,0.743) up-back; bulge toward -w1 (down-forward) looks like a bone sagging → organic: bend=-0.014 (applied as w*bend*sin → -w1 dir). Choose bend=+0.010 along +w1 (arching up-back)? Topology-optimized beams often bow against load — either fine; pick -0.012.\nLink1 length ~0.30-0.074=0.226 actual strut span ~ (E - u1*0.040) - (A1+u1*0.034): L_total 0.3061? A1=(0,0,0.165), E=(0.2229,0,0.3657) → |SE| = 0.30 (by construction L1=0.30). Strut span = 0.30-0.074=0.226.\n\nLink2 strut: A = E + u2*0.034, B = W - u2*0.036. span = L2 - 0.07 = 0.2848-0.07=0.215. dA=0.052, dB=0.034, rA=0.0080, rB=0.0058, n=11, bend -0.010.\n\nMembrane bays link1: bays [2,3, 7,8]? Choose 2 panels: bays 3 and 8 (0-indexed between nodes). Link2: bay 4. Also maybe one more on link1 bay 5? Leave X-braced middle bay open (shows lattice). Good: membranes at link1 bays 3,8; link2 bay 4.\n\nPanel corners from strut node positions — need the node coordinates; have strut function return node positions (tops,bots, and frame) for membrane & cable clip placement. \n\nAlso small collars where strut meets hubs: torus accent at strut ends? The swollen skin end nodes embed into hub cylinders — fine.\n\nNow small object \"machined\": \n- puck: r0.020 depth0.006 z0.003 alu\n- ring groove: torus accent r? skip\n- neck: r0.0115 depth0.014 center z0.013\n- head: r0.013 depth0.016 center z0.028, bevel 0.003 → total top 0.036\n- accent ring: torus major0.0125 minor0.0015 at z0.024 orange\n- top hex recess: hex cylinder r0.004 depth0.002 dark at z0.0365 embedded slightly? place top z0.0362 → looks like socket. Actually recess can't be boolean easily; fake with dark hex disc (reads as socket) ✓.\nPosition: obj_x = F.x + u3.x*0.02 = 0.4628+0.0059=0.4687 → (0.469, 0, ...). \n\nSecond small part: bearing: outer ring torus major0.009 minor0.0035 steel at (0.40, 0.11, 0.0035); inner torus smaller dark? plus few ball spheres r0.0018 ×6 around? cute detail: 6 chrome balls. Cheap, add.\n\nAlso a third tiny: washer torus r0.0045 minor0.0015 at (0.43,0.06). ok.\n\nDesk edge detail: add thin groove line on desk? skip.\n\nDesk lamp? Not needed; lighting is studio softboxes (invisible). But for orbit view, maybe add a physical softbox? No.\n\nFloor reflection: roughness 0.5 slight sheen.\n\nText/logo? skip.\n\nScene composition: also add a subtle backdrop wall panel behind desk at y=+1.4 for 2D render depth: plane 6×3 light gray at y=1.6? Camera FOV: from cam pos, background = world gray. Adding wall gives horizon line — cyclorama better. Let me build cyclorama: profile from floor (y=-2.5..1.2 flat) curving up at y=1.2..2.2 (radius 0.8) then vertical to z=3. Extruded along x -3..3. Build via mesh grid manually: sample profile points, create faces. Material same as floor or slightly lighter. This gives seamless studio sweep in main render; from orbit back views, you see the cove from behind (a curved shell) — acceptable, like a studio backdrop prop. Solidify not needed; give it thickness via Solidify modifier for orbit cleanliness.\n\nHmm, floor plane + cove overlapping: make cove floor section BE the floor (no separate plane) — cove extends y from -3 to vertical wall. Under desk region covered. Extend x ±4. Floor mat light gray. Desk stands on it.\n\nCamera & cove: cam at (0.95,-1.35,0.62)? Distance to target (0.22,0,0.18) = sqrt(0.73² + 1.35² + 0.44²)= sqrt(0.533+1.823+0.194)= sqrt(2.55)=1.597. Lens 58mm → vertical FOV 2*atan(18/58)=34.5° → frame height at target ≈ 2*1.597*tan(17.25°)=0.99 m. Scene height needed: from desk top (0) to elbow top 0.39 + margin, plus desk front edge below (z -0.05 at y=-0.5 → closer to camera, appears lower). ~0.6 m content vertical → fits with margin. Horizontal: arm x -0.1..0.55 (0.65) + base → fits 0.99 width easily. Maybe tighten: lens 65. Keep 60.\n\nDOF: focus distance ~1.55, f/6.3.\n\nAlso to ensure membrane transmission visible: lighting behind? rim light from +Y helps transmit. OK.\n\nNow write all code carefully with helpers. Watch out Blender 5.1 API details:\n\n- `bpy.ops.mesh.primitive_cylinder_add(radius=, depth=, vertices=, location=, rotation=)` — rotation as Euler; for axis alignment use quaternion.to_euler().\n- Materials: `mat.use_nodes=True`, nodes[\"Principled BSDF\"] inputs by name: 'Base Color','Metallic','Roughness','IOR','Alpha','Transmission Weight','Coat Weight','Emission Color','Emission Strength'. In 5.x emission input name 'Emission Color' ✓, transmission 'Transmission Weight' ✓.\n- World: `bpy.data.worlds.new`, use_nodes, Background node inputs 'Color','Strength'.\n- Color management: `scene.view_settings.look` — try 'AgX - Medium High Contrast'; wrap try.\n- Camera: `bpy.data.cameras.new`, lens, sensor_width; DOF: `cam.dof.use_dof=True; cam.dof.focus_object=empty; cam.dof.aperture_fstop=6.3`.\n- Lights: `bpy.data.lights.new(type='AREA')`, energy, shape='DISK'/'RECTANGLE', size.\n- Curve bevel.\n- Skin modifier: as discussed. One caution: `me.skin_vertices` requires modifier in stack; after `mod = ob.modifiers.new('Skin','SKIN')`, access `me.skin_vertices[0].data` — in some versions need `bpy.context.view_layer.update()` first. I'll add update call. Pattern widely used: works.\n- Subsurf modifier: `sub.subdivision_type='CATMULL_CLARK'`, levels.\n- Solidify for membrane.\n- Torus: `primitive_torus_add(major_radius=, minor_radius=, major_segments=48, minor_segments=12, location=, rotation=)` — torus axis default Z; align with axis via rotation.\n- Applying modifiers: use `bpy.context.view_layer.objects.active=ob; ob.select_set(True); bpy.ops.object.modifier_apply(modifier=...)`. To speed, could leave bevels unapplied (render fine, GLB exporter applies modifiers too). Leave modifiers unapplied! Less risk, faster. Render & export both evaluate. Keep bevel mods live. Only ensure normals fine.\n\n- For smooth shading selective: set polygons before adding bevel modifier: bevel output shading follows? Bevel faces inherit smooth? Bevel modifier has `segments` and produces faces with smooth shading derived from `harden_normals`/face smooth flags. With side faces smooth and caps flat on cylinders pre-bevel, result: bevel strips smooth — decent.\n\nActually simpler for cylinders: don't bevel small ones; bevel main housings. Set smooth sides via polygon loop.\n\nFor boxes: bevel modifier live, flat shading. Bevel on flat-shaded cube → bevel faces flat facets; with segments=3 visible faceting at close-up. Use segments=4 small width — ok.\n\nAlternatively shade box smooth + WeightedNormal modifier (exists in 5.1? \"WeightedNormal\" modifier still available in 4.x/5.x — yes, `NODES`? no, Weighted Normal modifier persists). I'll add WeightedNormal after Bevel for boxes with keep_sharp. If it errors, try/except pass. Hmm keep it: try/except.\n\nTime to also handle scene organization: put everything in one collection (default). Name objects semantically.\n\nRender engine: set 'CYCLES'. Also `scene.cycles.samples=64`, `scene.cycles.use_denoising=True`, resolution 1536. Device default; benchmark overrides. Set `scene.render.film_transparent=False`.\n\nAlso set `scene.render.image_settings.file_format='PNG'` and filepath? Not needed; benchmark renders. Skip filepath; save blend.\n\nUnit: `scene.unit_settings.system='METRIC'; scale_length=1.0`.\n\nLet me now write the geometry code in detail, computing frames.\n\nConstants recap (compute in code):\n```\nS = Vector((0,0,0.165))\na1 = radians(48)\nu1 = Vector((sin(a1),0,cos(a1)))\nL1 = 0.30\nE = S + u1*L1\nW = Vector((0.425,0,0.165))\nd = W-E; L2=d.length; u2=d/L2\ndelta = radians(28)\n# rotate u2 about Y by -delta (more downward): \nu3 = Vector(( u2.x*cos(delta)+(-u2.z)*sin(delta)?? ))\n```\nRotation about Y axis by angle φ: x' = x cosφ + z sinφ; z' = -x sinφ + z cosφ. Rotating u2 (which has negative z) further downward = rotate toward -z from u2... u2 angle θ2 = atan2(z,x) = -44.8°. Want θ3 = θ2 - 28°. So u3 = (cos(θ3), 0, sin(θ3)). Compute θ2 via atan2, then θ3 = θ2 - radians(28). Simple.\n\nv = Vector((0,1,0))\nw1 = u1.cross(v) → (u1.z*? ) compute: u1×v = (u1.y*v.z - u1.z*v.y, u1.z*v.x - u1.x*v.z, u1.x*v.y - u1.y*v.x) = (0*0 - u1.z*1, u1.z*0 - u1.x*0, u1.x*1 - 0) = (-u1.z, 0, u1.x) = (-0.669,0,0.743) ✓ up-back.\nw2 = (-u2.z, 0, u2.x) = (0.705,0,0.709) up-forward ✓.\nw3 = (-u3.z, 0, u3.x) = (0.955,0,0.296) ✓.\n\nFrames for oriented boxes: rotation matrix columns (u, v, w) → Matrix((u,v,w)).transposed() as 3x3 → to_4x4.\n\nHelper `place(name, obj_or_data...)`—I'll write:\n\n```python\ndef set_frame(obj, x, y, z, loc):\n    R = Matrix((x,y,z)).transposed().to_4x4()\n    R.translation = loc\n    obj.matrix_world = R\n```\nBut if object has un-applied scale (boxes set dimensions then apply scale before frame). For boxes: create cube, set dimensions, apply scale (bpy.ops.object.transform_apply) — need active object context; do before framing. Then set matrix_world.\n\nCylinder default along Z; frame with z-axis=u: set_frame(obj, x=v2?, y=?, z=axis). Provide orthonormal completion: given axis z, choose tmp = v(global Y) unless parallel; x = normalize(cross(tmp? )). For Y-axis cylinders: axis=(0,1,0): x = axis.cross((0,0,1))? Let me: given z_axis a: pick t = (0,0,1) if abs(a.z)<0.9 else (1,0,0); x = normalize(a.cross(t))? need orthonormal: x = normalize(t.cross(a))? Any consistent: \n```\nt = Vector((0,0,1)) if abs(a.z)<0.95 else Vector((1,0,0))\nx = a.cross(t).normalized()  # perpendicular\ny = a.cross(x).normalized()?? \n```\nCheck orthonormal right-handed: y = z.cross(x)? For matrix columns x,y,z with det +1: y = z × x. Set y = a.cross(x)? z×x = y by right-hand rule ✓ so y = a.cross(x).\n\nHmm a.cross(x) with x = a×t: a×(a×t) = a(a·t) - t(a·a) = a(a·t)-t → magnitude fine, direction = z×x ✓ correct.\n\nFor axis=Y: a=(0,1,0), t=(0,0,1): x = a×t = (1*1-0*0, 0*0-0*1, 0) = (1,0,0)? compute: a×t = (a.y*t.z - a.z*t.y, a.z*t.x - a.x*t.z, a.x*t.y - a.y*t.x) = (1*1-0, 0-0, 0-0) = (1,0,0). y = a×x = (0,1,0)×(1,0,0) = (1*0-0*0, 0*1-0*0, 0*0-1*1) = (0,0,-1). So cylinder Z→Y with x=(1,0,0), y=(0,0,-1) fine.\n\nMembrane panel builder returns object.\n\nRod between points:\n```python\ndef rod(p1,p2,r,mat,name,verts=16):\n    d=p2-p1; L=d.length\n    cyl at (p1+p2)/2 axis d/L\n```\n\nBolt ring:\n```python\ndef bolt_ring(center, axis, ring_r, n, br, bh, mat):\n    a=axis normalized; x,y basis\n    for k in range(n):\n        ang=2πk/n\n        p = center + x*(ring_r cos) + y*(ring_r sin)\n        hex bolt: cyl verts=6 radius br depth bh at p + a*(bh/2)?? \n```\nDecide bolt sits proud of face: center at face point + a*(bh*0.25) so embedded slightly. Add small washer disc under: cyl r=br*1.4 depth bh*0.3 at face+0.15bh. Keep both.\n\nBolts on faces with axis ±Y etc.\n\nLED: cyl r0.0025 depth0.0015 emissive mat + tiny dark bezel r0.0035.\n\nEmissive mat: Principled Emission Color (0.2,1.0,0.35), strength 6, base black.\n\nNow counts: bolts: base plate 4(+washers), turret plate 6, shoulder caps 8 (4/side small), hub collars? Let me include washers in bolt_ring by default.\n\nTotal objects maybe ~220 — fine.\n\nAlso to show \"replaceable interface plates\": at strut-hub junctions add collar plates: thin disc r=hub_r*1.08 depth 0.004 at hub-strut boundary + 4 micro bolts. Add for 4 hubs.\n\nAlso shoulder motor: cylinder r0.024 depth0.05 axis Y center (0,-0.081,0.165) + rear cap r0.025 depth0.006 center (0,-0.109,0.165) dark + LED? encoder disc on +Y cap instead. Add motor mounting flange r0.028 depth0.004 at y=-0.058.\n\nCheek top cover: rounded box over cheeks tops? cheeks at z up to 0.19; link passes... skip cover.\n\nMechanical stop: small block on cheek at angle limiting link1 backward motion: box (0.012,0.012,0.02) at (-0.035,-0.043,0.145)? hmm inside cheeks region between them is where hub moves; stop tabs on inner cheek faces behind hub: place small blocks at y=±0.033 (inner face ±0.036 minus half 0.0035), x=-0.030, z=0.150. Fine subtle.\n\nBase anti-slip ring under plate: thin dark disc r0.075 depth0.002 at z0.001? plate is 0.17 square; rubber ring torus major0.07 minor0.002 under? skip—plate on desk.\n\nAdd desk grommet? no.\n\nNow camera target empty + DOF empty.\n\nLights detail: \nkey = area, energy 800, size 0.9, loc (0.4,-1.1,1.7), rot toward target (0.25,0,0.2) — write point_light_at helper using rotation_difference on -Z (lights point -Z local).\nfill: energy 300, size 0.8, loc (-1.2,-0.5,0.8), color (0.85,0.90,1.0)\nrim: energy 700, size 0.5, loc (0.9,1.0,1.3) target (0.3,0,0.25) color (1.0,0.95,0.9)\ntop soft: energy 500 size 1.2 loc (0.1,0.2,2.2) target (0.2,0,0)\nAlso small area near gripper? skip.\n\nWorld strength 0.35 color (0.65,0.66,0.70).\n\nWith AgX medium-high contrast this should look premium.\n\nCheck membranes under Cycles: transmission needs `surface_render_method`? In 5.x, for transmission no alpha needed — works. Film thin w/ solidify ✓. IOR 1.38.\n\nGLB: transmission exported ✓.\n\nMembrane procedural bump noise — GLB bake might handle; keep subtle; actually risk of weird bake — keep bump very low (0.12) or skip? \"fine architectural mesh\" texture: use Noise scale 400 → bump strength 0.15 distance 0.0002. Fine, keep. Actually to reduce bake weirdness, keep it — benchmark says may bake supported procedural inputs; Noise→Bump→Normal is supported bake. OK.\n\nDesk material: slight noise bump? skip, clean laminate rough 0.4.\n\nFloor/cove: roughness 0.55.\n\nAlso add subtle imperfections to metals: Noise → roughness via ColorRamp tiny range (0.2-0.3)? Procedural noise scale 120 detail 2 → ramp → roughness. Keep simple: skip for robustness; set scalar roughness.\n\nActually crisp material separation is requested; plain scalar fine.\n\nOne more requirement: \"compact gearboxes\" — shoulder: add gearbox cylinder r0.034 depth0.03 axis Y at (0, 0.065, 0.165) on +Y side (opposite motor)? That's big vs cheeks outer 0.050 — mount on +Y outer face: center y=0.066 spans 0.051..0.081 r0.034 → around cap r0.030... overlapping cap; instead make +Y side the gearbox: replace cap on +Y with gearbox housing r0.032 depth 0.026 center y=0.063 + output flange. And -Y side: motor. Encoder small cap on motor rear. Do same pattern elbow (smaller): +Y gearbox r0.024 depth0.02 center y=0.047; -Y motor (already). Wrist: +Y side encoder cap r0.014; -Y motor.\n\nWait caps: I had caps both sides + nuts. Adjust: +Y: gearbox (shoulder), cap then at gearbox end: small cap r0.020 depth0.008 at y=0.080 + LED. Pin nuts both ends still fine at y=±0.085? Shoulder pin spans through everything y -0.115..0.085? Pin r0.011 from motor through to gearbox — pin visible between components? Pin hidden inside housings; show pin ends: extend pin to y=±0.088 with hex nuts at ends. Motor spans -0.056..-0.106 → pin inside motor invisible; nut at y=-0.112 on motor cap? Weird. Simpler: pin ends visible at gearbox front face (+Y) as bolted shaft collar: collar r0.014 depth0.006 at y=0.084 + center hex bolt r0.005. On -Y motor rear cap center hex r0.005. Reads as shaft clamps ✓.\n\nElbow: +Y gearbox r0.022 depth0.018 center y=0.046, collar r0.011 at y=0.057 hex r0.004; -Y motor r0.019 depth0.045 center y=-0.0585 cap r0.020 at -0.083, center hex. Encoder disc: thin dark cylinder r0.016 depth0.004 between motor and cheek? at y=-0.037. OK.\n\nWrist: +Y: encoder cap r0.013 depth0.010 center y=0.029, collar hex; -Y: motor r0.0125 depth0.030 center y=-0.038, cap.\n\nJoint axis visibility ✓ via pins/collars.\n\nLink1 root hub at A1 with cheeks — hub center A1+u1*0.008, r0.026 depth 0.06: spans A1-0.022..A1+0.038. Pin at A1 axis Y passes through hub ✓ (hub is cylinder around u1 through which Y-pin crosses — intersection geometry fine, cylinders overlapping okay visually as assembled).\n\nThrust washers shoulder: r0.013 depth0.003 axis Y at y=±0.0305 z0.165 — hub v-extent r0.026 at A1 → hub surface at y ±0.026 near A1... washers at ±0.0305 between hub and cheeks inner (±0.036) ✓.\n\nEverything plausible.\n\nBase rotation indicator: small index mark? skip.\n\nAlso add a subtle chamfer ring at hub-cylinder ends: torus? skip—bevel modifier on cylinders with width 0.002 covers edges. Bevel cylinders: add bevel modifier width ~0.0015-0.003 segments 3, angle limit. For small parts width 0.001.\n\nI'll add bevel param to cyl helper (default small) but skip applying; live modifiers.\n\nPerformance: ~250 objects each with bevel modifiers — Cycles fine.\n\nNow membrane bow direction ±v: choose +v? Film inside mid-plane with slight bow +v (toward camera back?) camera at -Y: +v bow faces away; slight, irrelevant. Use alternating bow per panel? Keep +0.0028 bow.\n\nAlso add tiny membrane edge frames? no.\n\nLet me also slightly tilt panels? no.\n\nDouble-check skin modifier usage in 5.1 — unchanged API I believe.\n\nSubsurf after skin: `sub.levels=2; sub.render_levels=3`? render 2 enough given small radii; 3 heavy. Use 2/2.\n\nSmooth shading for strut mesh: after from_pydata set all polys... skin mesh initially has no faces! from_pydata with edges only → no polys. Smooth shading applies to generated skin output: set via modifier? The Skin output polygons inherit... they may be flat → faceted tubes! Need smooth: after skin+subsurf, subsurf smooths normals? Subsurf produces smooth-ish shading only if faces smooth? Subsurf divides but shading flat per face unless smooth. To ensure smooth: add a \"Smooth by Angle\" via geometry nodes? Simplest: apply skin modifier, then set polys smooth, keep subsurf live. Applying skin: `bpy.ops.object.modifier_apply(modifier='Skin')` with context. Then set all polys smooth, then subsurf live. Skin result ~ (n=12 → verts maybe 300) fine.\n\nOrder: create mesh, add skin mod, set radii, apply skin, shade smooth, add subsurf. \n\nMembrane Solidify: live ok.\n\nCable curve bevel_resolution 3, resolution_u 12.\n\nEdge case: `me.skin_vertices` — after adding modifier, must ensure depsgraph update: call `bpy.context.view_layer.update()`. Then set radii; then apply modifier with ops (needs object active & selected in view layer — headless fine).\n\nAlternative safer: apply skin via evaluated mesh copy? Use ops straightforward; it's standard.\n\nAlso `use_root`: set on data vertex 0: `sv[0].use_root=True`? attribute exists: `SkinVertex.use_root` ✓. Also maybe needed `use_loose` no.\n\nOne concern: Skin modifier at branch nodes with 4 edges (middle X nodes have degree 4) — handles fine.\n\nRadii: skin radius tuple (rx, ry) equal.\n\nHub embed: strut end node radius rA*1.28=0.0147 vs hub r0.026 → embeds ✓. Elbow end 0.0085*1.28=0.0109 vs fork plates? link1 end has fork plates at y±0.030 + cross tube? I removed cross tube at elbow for link1; strut B = E - u1*0.040 with fork plates spanning E-0.035..E+0.015 along u1 → strut end embedded between plates region; add link1-end collar: cylinder axis u1 r0.020 depth0.045 center E-u1*0.030 — strut end node (r 0.0109) embeds into collar ✓ collar between fork plates (r0.020 < gap half 0.025) ✓.\n\nSimilarly link2 root eye box covers strut A end: eye dims (0.055 u2, 0.036 v, 0.040 w2) centered E+u2*0.012 → spans u2: E-0.0155..E+0.0395; strut A=E+u2*0.034 inside ✓. Plus collar plate at strut A: cyl axis u2 r0.019 depth0.008 at E+u2*0.038 + bolts micro.\n\nLink2 end: fork plates (u2) at W: plates dims (0.045,0.008,0.034) center W-u2*0.006 y±0.022 → span u2 W-0.0285..W+0.0165; strut B = W-u2*0.036 → gap! strut ends before plates start (W-0.036 < W-0.0285). Extend collar: cyl axis u2 r0.015 depth0.05 center W-u2*0.030 spans W-0.055..W-0.005 → covers strut end (W-0.036) ✓ and overlaps plates ✓. r0.015 fits between fork inner faces ±0.018 ✓.\n\nStrut A/B embed distances fine.\n\nBolts on fork plates: 2 small hex per plate + the pin cap.\n\nNow check link1 fork plates vs hub1 collar and pin: pin r0.007 at E spans y±0.05 → ends inside gearbox/motor housings at y ±0.046.. ✓ (gearbox center y0.046 spans 0.037..0.055; pin to ±0.05 ends inside; visible shaft collars on outer faces as designed).\n\nOK. Also elbow thrust washers r0.010 depth0.0025 at y=±0.020? eye v ±0.018, fork inner ±0.025: washers at ±0.021 ✓.\n\nWrist thrust washers r0.008 at y=±0.0175 (block r0.016 v-extent 0.016; fork inner ±0.018) ✓.\n\nNow cove mesh: profile pts (y,z): (-3.0,-0.80), (1.0,-0.80), then curve: center of arc at (1.0, -0.80+0.9)=(1.0,0.10)?? Arc radius 0.9: points for a in 0..90°: y = 1.0 + 0.9*sin(a), z = -0.80 + 0.9*(1-cos(a)): at a=90: y=1.9, z=0.10 → then vertical wall to z=3.2: (1.9, 3.2). Extrude x -3.5..3.5. Build grid: for each x in [-3.5,3.5] two columns; faces quads. Normals face -Y/-Z? Set material both sides (Cycles double-sided default ✓). Add Solidify thickness 0.05 for orbit view? With solidify live modifier fine.\n\nWait floor at z=-0.80 matches desk legs bottom -0.80 ✓.\n\nCove color: (0.62,0.62,0.64) rough 0.6? Slightly darker than desk for separation; lights will brighten.\n\nCamera at (0.98,-1.32,0.60), target (0.20,0.02,0.17). Lens 62. Compute later; fine.\n\nAlso add a soft rectangular \"reflector card\"? skip.\n\nExtra: tiny screws on interface plates — included via micro bolt rings.\n\nMicro bolts on collars: ring 4 r_ring=collar_r*0.72, br=0.0018, bh=0.0025 — tiny; at 1536px with object ~0.5m tall → 0.0018m ≈ 3px — visible barely; make br 0.0025. OK.\n\nAlso \"replaceable interface plates\" at gripper: the tool flange + body front plate (box 0.004 thick at s=0.083 with 4 micro bolts).\n\nName plate on base front: thin box (0.05,0.002,0.014) at (0.0,-0.062,0.030)? On base cylinder surface curved... place on plate front edge instead: (0,-0.086,0.008) small alu plate with fake engraved lines? skip engraving; plain plate ✓.\n\nLEDs: turret front (0,-0.0505,0.075)? turret r0.05 → surface y=-0.05 at x0: LED at (0.0,-0.051,0.075) axis Y green. Elbow motor cap LED amber at (E+(0,-0.086,0)) axis Y. Wrist motor cap LED green (W+(0,-0.056,0)). Controller LED green top. Gripper body LED? maybe on body -v face at s=0.060: point W+u3*0.060+v*(-0.0205) axis -v... body v half 0.020 → face at -0.020 → LED at -0.0215. Amber. ✓ (5 LEDs).\n\nEmission strength 8 small.\n\nCheck no part intersects desk (z<0): base plate z 0..0.014 ✓ all above.\n\nAlso verify link1 strut doesn't hit turret: strut A at A1+u1*0.034 = (0.0253,0,0.1877) region above turret top 0.101 ✓.\n\nCheek plates: from z 0.101 to 0.19: dims z 0.089 center z 0.1455 x dims 0.06 centered x -0.005? Pin at (0,·,0.165) should be within plate: plate x span -0.035..0.025, z 0.101..0.190 ✓. Cheeks bolted to turret top: 4 small bolts each? two per cheek into turret top at (±0.02, ±0.043, 0.101) axis Z? bolts vertical r0.003. Add.\n\nAlso turret top plate bolts 6 ring r0.042 on plate z0.101 top... plate spans z 0.093..0.101, bolts on top face ring 0.042 r0.003 h0.004 ✓.\n\nBase lower cylinder r0.062 z 0.014..0.046; turret r0.05 z 0.058..0.093; ring z 0.046..0.058 dark r0.056; accent ring r0.057 z 0.0565..0.0595? overlap dark ring edge — accent at z 0.057 depth0.002 r0.0565.\n\nUnder-plate rubber pad: dark cylinder r0.075 depth0.002 z0.001? plate square 0.17 — pad circle smaller hidden. skip.\n\nController cable port on base: grommet at (0,-0.058,0.024) r0.006 depth0.006 axis Y dark on lower base cylinder r0.062: surface at y=-0.062 (x=0,z=0.024 vs cyl center z=0.030: offset dz=-0.006 → y_surface = -sqrt(0.062²-0.006²)=-0.0617) place grommet y=-0.060 half-embedded ✓.\n\nAlso add small vertical cable from turret into base? J1 slip ring implied; skip.\n\nEverything set. Also \"recessed cable guides\": add slim channel on link1: thin dark box under strut? The clips suffice. Add 3 clips per link: tiny torus around cable? clips as small boxes bridging cable to beam: at t values, box center p_clip = centerline(t) - w*(depth/2+?) ... cable at offset -w*0.05; clip box from beam surface to cable: center at -w*0.030 dims (0.010 u, 0.016 v, 0.045 w) dark — a slim bracket ✓ oriented frame(u1,v,w1). But strut bottom rail is at -w*h(t); h(t) ~0.02-0.045; clip from rail to cable: position relative bottom rail: rail_z = -h(t); cable at -0.05. Clip center at -(h(t)+0.05)/2 height (h(t)-0.05)... compute per clip: h = h(t)+node radius ~ h(t)+0.009. clip center offset o = (h + 0.05)/2, dims w = 0.05 - h + 0.008. If h>0.05 cable inside section?? h(t) max ~ dA/2*1.15 = 0.046 + radius → ~0.055 > 0.05 at ends! Cable at -0.05 could clip rails near ends. Set cable offset -0.065 to clear (max rail ~0.055+0.011=0.066 hmm at t small h=0.046 radius 0.0147 → surface 0.0607). Cable at -0.068 clears (cable r 0.0022 → 0.0658 vs 0.0607 ✓ barely). Use -0.072 safe. Clips bridge 0.0607..0.072 — clip dims w ~0.02 center -(0.0607+0.072)/2≈-0.066. Compute per-clip in code using h(t)+rad(t) as surface.\n\nLink2: max h = 0.052/2*1.15=0.0299+rad 0.0102 → 0.040. cable offset -0.050, clips accordingly.\n\nCable visible neat under beams ✓ camera sees front (-Y) and below slightly — cables at y=-0.028/-0.024 (front-ish) ✓.\n\nCable endpoints link1: start near turret port at (S + v*(-0.028) - w1*0.02 + u1*0.01, z?) turret top z0.101: start pt (0.008,-0.028,0.108); then clips t=0.25,0.5,0.75 positions along strut underside; end at elbow motor cap (E + v*(-0.084) + w2*0.0?) motor center y -0.0585 cap at -0.083; end point (E.x, -0.083, E.z+0.01). Path AUTO smooth.\n\nPoints count: start, pre-clip (t=0.15), clip1 t=0.30, clip2 t=0.55, clip3 t=0.75, end. Each pt = centerline(t) - w1*0.072 + v*(-0.028).\n\nWait between t=0.85..end cable should curve to motor at y=-0.083: last two pts transition v offset: t=0.9 with v -0.06, then end. ok.\n\nLink2 cable similar from elbow motor top region to wrist motor: start (E+v*(-0.084)+w? start at motor cap top: (E.x, -0.083, E.z+0.012)) hmm same cap both cables attach — fine (two ports). pts along -w2*0.050 + v*(-0.024); end at wrist motor cap (W + v*(-0.056) + w2*0.0) → (W.x, -0.056, W.z).\n\nServo cable as before.\n\nTotal cables: 5. \n\nNow write final code. Also remember: create collections? single fine.\n\nAlso set object names meaningful.\n\nPotential heavy: skin apply ×2 + subsurf — fine.\n\nMembrane grid 8×8 with solidify live + smooth: ok.\n\nEdge case: `primitive_torus_add` signature in 5.x: `major_radius`, `minor_radius`, `abso_major_rad`? In 4.x/5.x it's major_radius/minor_radius with mode 'MAJOR_MINOR' default? The operator uses `major_radius` (outside?) Actually bpy.ops.mesh.primitive_torus_add(align='WORLD', location, rotation, major_segments, minor_segments, mode='MAJOR_MINOR', major_radius=1.0, minor_radius=0.25, abso_major_rad, abso_minor_rad, generate_uvs). With mode MAJOR_MINOR, major_radius = distance center-to-center ✓.\n\nFor axis alignment of torus (default axis Z) use same frame helper.\n\nWrite hex bolt helper:\n```python\ndef bolt(p, axis, r=0.003, h=0.004, mat=steel, washer=True):\n    if washer: cyl(r*1.5, h*0.35, p + axis*h*0.175, axis, verts=24, mat, bevel=0)\n    cyl6 = cyl(r, h, p+axis*(h*0.35+ h/2 ... \n```\nLet me define: washer disc center p + axis*(0.0006), depth 0.0012; head center p + axis*(0.0012 + h/2), depth h. Return.\n\nSimplify: `bolt(p, axis, r, h)`: washer depth 0.3h? Proportions fine.\n\nNow object/orbit robustness: everything 3D from all angles ✓.\n\nSave blend: try/except path: `bpy.ops.wm.save_as_mainfile(filepath='/tmp/robot_arm.blend')`? Unknown writable; use `bpy.path.abspath('//robotic_arm.blend')`. If cwd writable ok. Wrap try/except. Actually harness likely saves itself; but instruction says save complete scene — I'll attempt save to '//blender_bench_scene.blend' in try.\n\nAlso ensure camera set: `scene.camera = cam_obj`.\n\nSet render res 1536, engine cycles, samples 64, denoise.\n\nSet film_transparent False.\n\nTransparent shadows? n/a.\n\nExposure: `scene.view_settings.exposure=0`.\n\nAgX look: try 'AgX - Medium High Contrast' except try 'AgX - Medium High Contrast' variants: in 5.x look enum values might be 'AgX - Medium High Contrast' (same as 4.2). Wrap in try/except, fallback none.\n\nNow compose the code.\n\n```python\nimport bpy, math\nfrom math import sin, cos, pi, radians, atan2, sqrt\nfrom mathutils import Vector, Matrix\n\n# ---------- scene reset ----------\nbpy.ops.object.select_all(action='SELECT')\nbpy.ops.object.delete(use_global=False)\nfor d in (bpy.data.meshes, bpy.data.curves, bpy.data.materials, bpy.data.cameras, bpy.data.lights):\n    pass  # keep default cleanup minimal\n\nscene = bpy.context.scene\nscene.render.engine = 'CYCLES'\nscene.cycles.samples = 64\nscene.cycles.use_denoising = True\nscene.render.resolution_x = 1536\nscene.render.resolution_y = 1536\nscene.render.resolution_percentage = 100\nscene.render.image_settings.file_format = 'PNG'\nscene.unit_settings.system = 'METRIC'\ntry: scene.view_settings.look = 'AgX - Medium High Contrast'\nexcept: pass\n```\n\nMaterials helper:\n\n```python\ndef mat_principled(name, color, metallic=0.0, rough=0.4, transmission=0.0, ior=1.45, emission=None, estr=0.0, coat=0.0):\n    m=bpy.data.materials.new(name); m.use_nodes=True\n    bs=m.node_tree.nodes['Principled BSDF']\n    bs.inputs['Base Color'].default_value=(*color,1)\n    bs.inputs['Metallic'].default_value=metallic\n    bs.inputs['Roughness'].default_value=rough\n    if transmission>0:\n        bs.inputs['Transmission Weight'].default_value=transmission\n        bs.inputs['IOR'].default_value=ior\n    if coat>0: bs.inputs['Coat Weight'].default_value=coat\n    if emission is not None:\n        bs.inputs['Emission Color'].default_value=(*emission,1)\n        bs.inputs['Emission Strength'].default_value=estr\n    return m\n```\n\nMembrane material with noise bump:\n\n```python\nm = mat_principled(...)\nnt=m.node_tree; bs=nt.nodes['Principled BSDF']\nnoise=nt.nodes.new('ShaderNodeTexNoise'); noise.inputs['Scale'].default_value=350; noise.inputs['Detail'].default_value=2.0\nbump=nt.nodes.new('ShaderNodeBump'); bump.inputs['Strength'].default_value=0.12; bump.inputs['Distance'].default_value=0.0003\nnt.links.new(noise.outputs['Fac'], bump.inputs['Height']); nt.links.new(bump.outputs['Normal'], bs.inputs['Normal'])\n```\n\nHelpers: assign_mat(obj,mat); frame basis; cyl; box; torus; bolt; rod; cable; look_at.\n\n```python\ndef frame_from_axis(axis, hint=Vector((0,0,1))):\n    z=Vector(axis).normalized()\n    t = Vector((0,0,1)) if abs(z.z)<0.95 else Vector((1,0,0))\n    x = z.cross(t).normalized()\n    y = z.cross(x).normalized()\n    return x,y,z\n\ndef set_frame(obj, x,y,z, loc):\n    M=Matrix((x,y,z)).transposed().to_4x4(); M.translation=Vector(loc)\n    obj.matrix_world=M\n```\n\ncyl:\n\n```python\ndef cyl(name, r, depth, loc, axis=(0,0,1), mat=None, verts=48, bevel=0.0, smooth=True):\n    bpy.ops.mesh.primitive_cylinder_add(vertices=verts, radius=r, depth=depth, location=loc)\n    o=bpy.context.active_object; o.name=name\n    x,y,z=frame_from_axis(axis)\n    set_frame(o,x,y,z,loc)\n    if mat: o.data.materials.append(mat)\n    if smooth:\n        for p in o.data.polygons: p.use_smooth = len(p.vertices)==4\n    if bevel>0:\n        mod=o.modifiers.new('bev','BEVEL'); mod.width=bevel; mod.segments=3; mod.limit_method='ANGLE'\n    return o\n```\n\nWait: setting matrix_world after creation at location: created with location=loc, rotation identity; then set_frame overrides including translation — fine.\n\nbox:\n\n```python\ndef box(name, dims, loc, frame=None, mat=None, bevel=0.0):\n    bpy.ops.mesh.primitive_cube_add(size=1, location=loc)\n    o=bpy.context.active_object; o.name=name\n    o.dimensions=dims\n    bpy.ops.object.transform_apply(location=False, rotation=False, scale=True)\n    if frame: set_frame(o, *frame, loc)\n    ...\n```\ntransform_apply requires active/selected: after primitive add, it's active ✓.\n\ntorus:\n\n```python\ndef torus(name, R, r, loc, axis=(0,0,1), mat=None):\n    bpy.ops.mesh.primitive_torus_add(major_radius=R, minor_radius=r, major_segments=48, minor_segments=12, location=loc)\n    o=...; set_frame with axis; smooth all polys\n```\n\nbolt:\n\n```python\ndef bolt(name, p, axis, r, h, mat):\n    a=Vector(axis).normalized()\n    cyl(name+'_w', r*1.6, h*0.3, Vector(p)+a*(h*0.15), axis, mat, verts=24, bevel=0)\n    cyl(name+'_h', r, h, Vector(p)+a*(h*0.3+h*0.5), axis, mat, verts=6, bevel=0, smooth=False)\n```\n\nbolt_ring(center, axis, ring_r, n, r, h, mat, phase=0): basis x,y from frame_from_axis(axis): p = center + x*cos*ring_r + y*sin*ring_r.\n\nrod(p1,p2,r,mat,name).\n\ncable(points,r,mat,name).\n\nlook_at(obj, target, track='-Z', up='Y'): use quaternion: \n```python\nd = Vector(target)-obj.location\nobj.rotation_euler = d.to_track_quat('-Z','Y').to_euler()\n```\nFor lights same.\n\nStrut function (returns nodes + frame info):\n\n```python\ndef optimized_strut(name, A, B, dA, dB, rA, rB, bend, n, mat, x_bay=True):\n    A=Vector(A); B=Vector(B); u=(B-A); L=u.length; u.normalize()\n    v=Vector((0,1,0))\n    w=u.cross(v).normalized()\n    v=w.cross(u).normalized()  # ensure orthogonal (v stays ~Y)\n```\nCheck: u×v with v=(0,1,0): for u in XZ plane, u×v = (-u.z,0,u.x) ✓ =w; then v' = w×u: (w.y*u.z-w.z*u.y, w.z*u.x-w.x*u.z, w.x*u.y-w.y*u.x) = (0, w.z*u.x - w.x*u.z? compute: w=(-uz,0,ux): w×u = (0*u.z - u.x*u.y? let me just trust: w×u with both in XZ, v'=(0,?,0): y-comp = w.z*u.x - w.x*u.z = ux*ux - (-uz)(uz)= ux²+uz²=1 → v'=(0,1,0) ✓.\n\n    nodes & edges & radii as planned; returns dict with tops,bots coords, u,v,w, h(t), etc.\n\nSkin build:\n\n```python\n    me=bpy.data.meshes.new(name)\n    me.from_pydata([tuple(p) for p in verts], edges, [])\n    ob=bpy.data.objects.new(name,me)\n    bpy.context.collection.objects.link(ob)\n    sk=ob.modifiers.new('Skin','SKIN')\n    bpy.context.view_layer.update()\n    sv=me.skin_vertices[0].data\n    for i in range(len(sv)): sv[i].radius=(radii[i],radii[i])\n    sv[0].use_root=True\n    bpy.context.view_layer.objects.active=ob\n    ob.select_set(True)\n    bpy.ops.object.modifier_apply(modifier='Skin')\n    for p in me.polygons: p.use_smooth=True\n    sub=ob.modifiers.new('Sub','SUBSURF'); sub.levels=2; sub.render_levels=2\n    ob.data.materials.append(mat)\n```\n\nmodifier_apply on non-selected? ensure selected: after link, select only it: `bpy.ops.object.select_all(action='DESELECT')` then select. ok.\n\nMembrane panel:\n\n```python\ndef membrane(name, c00,c10,c11,c01, normal, mat, bow=0.0028, nx=8, ny=8, inset=0.10):\n    C=(c00+c10+c11+c01)/4\n    def ins(p): return p+(C-p)*inset\n    P=[ins(c00),ins(c10),ins(c11),ins(c01)]\n    verts=[]; faces=[]\n    for j in range(ny+1):\n        s=j/ny\n        for i in range(nx+1):\n            r=i/nx\n            p=(1-r)*(1-s)*P[0]+ r*(1-s)*P[1]+ r*s*P[2]+ (1-r)*s*P[3]\n            p=p+Vector(normal)*(bow*sin(pi*r)*sin(pi*s))\n            verts.append(tuple(p))\n    for j in range(ny):\n        for i in range(nx):\n            a=j*(nx+1)+i; faces.append((a,a+1,a+nx+2,a+nx+1))\n    me=...from_pydata(verts,[],faces)\n    ob=...; \n    for p in me.polygons: p.use_smooth=True\n    sol=ob.modifiers.new('Solid','SOLIDIFY'); sol.thickness=0.0011; sol.offset=0\n    ob.data.materials.append(mat)\n```\n\nInset 0.10 relative each corner → gap ~10% of bay size (~0.02*0.1=2mm?) bay ~20mm long, 30mm tall → inset ~2-3mm from rails: with rail radius ~9mm, film edge well under rails?? inset moves corner toward centroid by 10% of diagonal — gap between film edge and rails ~ small; rails cover seam from camera? Not exactly but fine visually (film slightly inside frame). Use inset 0.06.\n\nThen main assembly code — long but straightforward. Let me write positions concretely.\n\nBase:\n```\nplate: box dims (0.17,0.17,0.014) loc (0,0,0.007) bevel 0.008, dark\n4 bolts at (±0.072,±0.072,0.014) axis +Z r0.0045 h0.005\nbase_lower: cyl r0.062 d0.032 loc(0,0,0.030) alu bevel0.004\nring_dark: cyl r0.056 d0.012 loc(0,0,0.052) darksteel? use mat_dark\nring_accent: cyl r0.0568 d0.0022 loc(0,0,0.057) accent\nturret: cyl r0.050 d0.036 loc(0,0,0.076) alu bevel0.004\ntopplate: cyl r0.055 d0.008 loc(0,0,0.098) dark bevel0.002\ntopplate bolts ring r0.043 n6 r0.0028 h0.0035 at z0.102 axis Z\nturret LED at (0,-0.0508,0.076) axis -Y? LED cyl axis Y at (0,-0.0505,0.076): bezel dark r0.0035 d0.002, led r0.0022 d0.001 emissive — position slightly proud: bezel center (0,-0.0498,0.076) depth 0.002 axis Y → spans -0.0508..-0.0488 half in turret. ok.\ncheeks: boxes dims (0.060,0.014,0.089) loc (-0.005,±0.043,0.1455) bevel0.006 alu\ncheek bolts: 2 per cheek into top plate: at (-0.02/0.012, ±0.043, 0.103) axis Z r0.0025 h0.003\ngearbox(+Y): cyl r0.032 d0.026 loc(0,0.063,0.165) axis Y dark? make alu with dark cap:\n  gb housing alu bevel0.004; gb cap r0.020 d0.008 loc(0,0.080,0.165) dark; collar r0.013 d0.006 loc(0,0.086,0.165) steel; center hex bolt r0.0045 h0.004 at (0,0.089,0.165) axis Y.\n  gb bolts ring r0.024 n4 r0.0022 on face y=0.0775 axis +Y? place ring on cap front y0.0845.\nmotor(-Y): flange cyl r0.028 d0.005 loc(0,-0.053,0.165) dark; housing r0.024 d0.048 loc(0,-0.079,0.165) alu bevel0.004; cap r0.0245 d0.006 loc(0,-0.106,0.165) dark; collar r0.011 d0.005 loc(0,-0.110,0.165) steel + hex r0.004.\npin visual: shaft collars done; actual pin cyl r0.0105 d0.17 loc(0,0,0.165) axis Y steel (hidden mostly, ends into collars).\nthrust washers: cyl r0.0135 d0.003 loc(0,±0.0305,0.165) axis Y steel.\nstop tabs: boxes dims(0.014,0.010,0.018) loc(-0.032,±0.030,0.148) dark bevel0.002\nnameplate: box dims(0.055,0.002,0.016) loc(0,-0.0862,0.007)?? plate front edge at y=-0.085; plate z center 0.007 → nameplate on front face: loc(0,-0.0855,0.007) dims(0.05,0.002,0.010) alu. ok.\n```\n\nLink1 root hub: cyl r0.026 d0.062 axis u1 loc A1+u1*0.008 bevel0.004 alu; collar plate at strut side: cyl r0.029 d0.005 axis u1 loc A1+u1*0.040 dark; micro bolts ring on collar face at A1+u1*0.0435 axis u1 ring r0.022 n4 r0.002 h0.003.\n\nStrut1: A=A1+u1*0.036 → hub spans to A1+0.039: strut A inside collar ✓ (A at 0.036 within collar 0.0375..0.0425? collar center 0.040 depth0.005 spans 0.0375..0.0425; strut start node at 0.036 slightly before collar → inside hub (ends 0.039) ✓.\nB=E-u1*0.040. Link1 end collar: cyl r0.020 d0.05 axis u1 loc E-u1*0.028 spans E-0.053..E-0.003 → covers B(0.040→ E-0.040 inside ✓). r0.020 between fork inner faces ±0.025 ✓. micro bolts ring at E-u1*0.048 face? collar face at E-0.053: ring there axis -u1 r0.014 n4.\nFork plates link1-end: boxes dims(0.052,0.010,0.046) frame(u1,v,w1) loc E-u1*0.008 + v*±0.030, bevel0.005. Plate spans u: E-0.034..E+0.018.\nFork plate bolts: 2 per plate at E-u1*0.020/E+u? on outer faces axis v... skip (pin caps exist).\nPin: cyl r0.007 d0.10 axis Y loc E steel; thrust washers r0.0105 d0.0025 at y=±0.0215 axis Y loc (E.x,±0.0215,E.z).\nGearbox(+Y): r0.022 d0.018 loc(E.x,0.046,E.z); cap r0.014 d0.006 y0.058; collar r0.009 y0.0625 steel; hex r0.0035.\nMotor(-Y): flange r0.021 d0.004 y-0.037; housing r0.019 d0.044 y-0.060; cap r0.0195 d0.005 y-0.0845; collar r0.009 y-0.088; LED amber at (E.x,-0.0875,E.z+0.008)? place on cap face: bezel r0.003 at y-0.0878 z E.z; led.\nHmm motor housing from -0.038..-0.082 ✓ overlaps fork outer (0.035) ✓ flange between.\n\nLink2 root eye: box dims(0.056,0.036,0.040) frame(u2,v,w2) loc E+u2*0.012 bevel0.012 alu. Spans u2: E-0.016..E+0.040.\nRoot collar at strut side: cyl r0.0195 d0.006 axis u2 loc E+u2*0.041 dark + micro bolts ring r0.014 n4 at face E+u2*0.0445 axis u2.\nStrut2: A2=E+u2*0.038 (inside collar/eye ✓ eye ends 0.040, collar 0.038..0.044) → strut start node at 0.038 embedded ✓. B2=W-u2*0.034.\nLink2 end collar: cyl r0.015 d0.05 axis u2 loc W-u2*0.028 spans W-0.053..W-0.003 ✓ covers B2.\nFork plates link2-end: dims(0.046,0.008,0.034) frame(u2,v,w2) loc W-u2*0.006+v*±0.022 bevel0.004. spans u: W-0.029..W+0.017. inner faces y±0.018 ✓ collar r0.015 fits.\nPin: r0.005 d0.072 axis Y loc W. thrust washers r0.0085 d0.002 y±0.017.\nEncoder(+Y): housing r0.0135 d0.012 loc(W.x,0.024,W.z) alu; cap r0.010 d0.005 y0.0325 dark; collar r0.006 y0.036 steel hex.\nMotor(-Y): flange r0.014 d0.004 y-0.020; housing r0.0125 d0.030 y-0.037; cap r0.013 d0.005 y-0.0545; LED green y-0.0575.\nWrist block: cyl r0.016 d0.034 axis Y loc W alu bevel0.003 (rotating part between forks: v ±0.017 vs inner ±0.018 ✓).\n\nRoll actuator: base collar r0.0165 d0.004 axis u3 at W+u3*0.002 dark? Actually block r0.016 axis Y; actuator must attach to block face oriented u3 — the block is cylinder along Y; its surface around... The actuator cylinder r0.0145 d0.034 axis u3 loc W+u3*0.019 partially embedded in block (r0.016) ✓ intersection fine (assembled).\nAccent ring: torus R0.0148 r0.0016 axis u3 at W+u3*0.037.\nFlange: cyl r0.019 d0.006 axis u3 loc W+u3*0.041 dark? steel? make alu dark: dark. bolts ring r0.014 n4 r0.002 h0.0028 at face W+u3*0.0445 axis u3 steel.\nBody: box dims(0.036,0.040,0.024) frame(u3,v,w3) loc W+u3*0.065 bevel0.005 dark. spans s0.047..0.083.\nFront plate: box dims(0.004,0.036,0.020) loc W+u3*0.0845 bevel0.001 alu + 4 micro bolts r0.0016 at corners? place ring n4 r0.011 axis u3 face s0.0868.\nServo: cyl r0.0085 d0.020 axis w3 loc W+u3*0.058+w3*0.020 alu; cap r0.0088 d0.004 dark at w3*0.031; servo flange r0.010 d0.003 at w3*0.011 dark.\nBody top recess? skip.\nRails: at s=0.092: rods axis v r0.0028 d0.044 loc W+u3*0.092 ± w3*0.0065 steel.\nHmm front plate spans v ±0.018; rods to ±0.022 held by end plates at y±0.0225: end plates box dims(0.020,0.004,0.018) frame loc W+u3*0.092+v*±0.0225 bevel0.002 alu.\nWait rods at s=0.092 beyond front plate (0.083..0.0865)... rods floating held only by end plates which attach to?? End plates need connection to body: extend end plates backward: dims u 0.026 → from s0.079..0.105 overlapping body front (to 0.083) ✓ attach visually + micro bolt each. Carriages at s=0.095 y±0.017 dims(0.014,0.009,0.016) bevel0.002 steel-dark? machined alu.\nCarriage spans u 0.088..0.102 ✓ around rods (0.092) ✓. Rods thread carriage v-range 0.0125..0.0215? carriage y center 0.017 half 0.0045 → 0.0125..0.0215; rods at w3 ±0.0065 within carriage w3 half 0.008 ✓.\nPivot pins: cyl r0.0032 d0.012 axis v loc W+u3*0.092+v*±0.017 steel + cap discs r0.0048 d0.0015 at v±0.0232.\nFinger plates: dims(0.046,0.0045,0.012) loc W+u3*0.107+v*±0.017 bevel0.0015 alu. spans s0.084..0.130.\nPads: dims(0.012,0.0030,0.010) loc W+u3*0.124+v*±0.01525 pad mat bevel0.001. inner faces ±0.01375 → gap 0.0275. object head r0.013 dia 0.026 ✓.\nPad bolts: 2 micro per pad outer face? skip.\nLinkage rods: P1=W+u3*0.058+w3*0.028 (servo nose area → servo spans w3 0.010..0.030: nose at 0.030; P1 at 0.028 inside? set P1 = W+u3*0.058+w3*0.0305) to P2=W+u3*0.100+v*±0.017+w3*0.0075. r0.0016 steel. plus tiny clevis cylinders at ends r0.0025 d0.003? skip.\nBody LED amber: at W+u3*0.060+v*(-0.0206) axis -v: bezel+led.\nGripper cable: points: W+v*(-0.014)+w3*0.010? start at wrist motor? start at wrist block: (W+v*(-0.017)+w2*0.005) → mid W+u3*0.030+v*(-0.020)+w3*0.006 → end servo W+u3*0.058+w3*0.020+v*(-0.006)? servo at w3 0.020 center; cable enters servo side: end W+u3*0.058+w3*0.020+v*(-0.009). r0.0016.\n\nObject placement: F=W+u3*0.130 → obj_x=F.x+u3.x*0.018.\n\nCompute numeric sanity: u2: Δ=(0.425-0.2229, 0.165-0.3657)=(0.2021,-0.2007) L2=0.2848 u2=(0.7097,-0.7045)?? u2=(0.7097,0,-0.7045). θ2=atan2(-0.7045,0.7097)=-44.77°. θ3=-72.77°: u3=(cos,0,sin)=(0.2957,0,-0.9553).\nW=(0.425,0,0.165). F=(0.425+0.0384,0,0.165-0.1242)=(0.4634,0,0.0408). obj_x=0.4634+0.0053=0.4687 ✓. Pads z: 0.165-0.1185=0.0465 ±0.005 → bottom 0.0415 vs obj top 0.036 gap 5.5mm ✓.\n\nElbow E=(0.2229,0,0.3657) ✓.\n\nStrut1: A=A1+u1*0.036=(0.0268,0,0.1891); B=E-u1*0.040=(0.1932,0,0.3389). \nStrut2: A2=E+u2*0.038=(0.2499,0,0.3389)?? E+u2*0.038=(0.2229+0.0270,0,0.3657-0.0268)=(0.2499,0,0.3389). B2=W-u2*0.034=(0.425-0.0241,0,0.165+0.0239)=(0.4009,0,0.1889).\n\nMembrane bays: strut1 n=12 bays idx 3 and 8; strut2 n=11 bay 5 (also X at mid bay 5? x_bay mid = n//2: strut2 mid=5 → X there; choose membrane bay 4 and 7? pick bay 4). Strut1 X at bay 6.\n\nCables: \nc1 base internal: [(0.0,-0.112,0.150)?? motor rear cap at y-0.106..-0.109 z0.165: start (0,-0.109,0.158), ( -0.005,-0.095,0.125), (-0.015,-0.06,0.106), (-0.022,-0.035,0.103)] port grommet at (-0.022,-0.033,0.102) r0.005 dark axis Z? turret top at z0.094..? turret spans 0.058..0.094; topplate 0.094..0.102. Port on topplate edge... place grommet cyl r0.005 d0.006 at (-0.022,-0.033,0.100) axis Z dark ✓ cable end there.\n\nc2 link1: pts: start (0.010,-0.026,0.106)?? another grommet at (0.012,-0.026,0.100). Then t=0.12: centerline S+u1*(0.30*0.12)=S+u1*0.036=(0.0267,0,0.1891) offset -w1*0.072 → w1=(-0.669,0,0.743): -w1*0.072=(0.0482,0,-0.0535) → pt (0.0749,-0.026,0.1356). Hmm at t=0.12 the strut is near hub r0.026... cable at 0.072 below centerline — clear of hub (0.026) ✓.\n t=0.30: cl=(0.0669,0,0.2254) → +(0.0482,0,-0.0535)=(0.1151,-0.026,0.1719)\n t=0.55: cl=(0.1226,0,0.2755) → (0.1708,-0.026,0.2220)\n t=0.78: cl=(0.1738,0,0.3216) → (0.2220,-0.026,0.2681)\n end: elbow motor cap top: (E.x,-0.086, E.z+0.005) = (0.2229,-0.086,0.3707)\nTransition from v-0.026 to -0.086 at end — AUTO handles smooth S. Maybe add pt t=0.90 v-0.05: cl=(0.2008,0,0.3458)-w1*0.072=(0.249,-0.05,0.292)+ ... fine.\n\ncable radius 0.0022 mat_cable.\n\nclips at t=0.30,0.55,0.78: surface offset h(t)+rad(t): compute in code; clip box dims (0.012,0.018, surface+0.072+0.004)?? clip from strut surface to cable: center offset -( (h+r) + 0.072 )/2 along w1; dims w = 0.072-(h+r)+0.006. Compute h(t), rad(t) via same formulas — replicate in clip loop using strut dict (store function closures). I'll have strut return dict with 'h' and 'rad' lambdas and frame.\n\nc3 link2: start elbow motor cap (0.2229,-0.086,0.3707)? same cap two cables ok → start (0.2259,-0.086,0.3727) slight offset. pts along strut2 -w2*0.050 v-0.024: w2=(0.7045,0,0.7097): -w2*0.05=(-0.0352,0,-0.0355).\n t=0.15: cl=E+u2*(L2*0.15)=E+u2*0.0427=(0.2532,0,0.3356) → (0.2180,-0.024,0.3001)\n t=0.40: cl=(0.3036,0,0.2855)→(0.2684,-0.024,0.2500)\n t=0.65: cl=(0.3541,0,0.2354)→(0.3189,-0.024,0.1999)\n t=0.88: cl=(0.3989? compute E+u2*0.2506=(0.4008,0,0.1892))→(0.3656,-0.024,0.1537)\n end wrist motor cap: (W.x,-0.056,W.z+0.004)=(0.425,-0.056,0.169)\nclips similar with strut2.\n\nc4 servo cable (above).\nc5 controller cable.\nc1? included.\n\nController box: loc(-0.20,-0.13,0.016) dims(0.10,0.070,0.032) bevel0.006 dark; lid plate dims(0.09,0.06,0.003) loc z0.0335 alu dark? top plate steel-ish dark; LED green at (-0.175,-0.145,0.035) axis Z; port grommet front (facing base): at (-0.155,-0.105,0.014) r0.0045 axis? direction toward base: yaw... place on box face +x side: face at x=-0.15: grommet cyl r0.0045 d0.005 axis X at (-0.149,-0.115,0.014)? box x span -0.25..-0.15 ✓ y -0.165..-0.095: y=-0.115 ✓.\nCable pts: [(-0.146,-0.115,0.014),(-0.10,-0.105,0.005),(-0.05,-0.085,0.004),(-0.015,-0.070,0.005),(0.0,-0.062,0.016)] end at base grommet (0,-0.060,0.020) r0.005 axis Y at (0,-0.0595,0.022)?? base_lower r0.062 center z0.030: at z0.022 dy = sqrt(0.062²-0.008²)=0.0615 → grommet at (0,-0.0605,0.022) axis Y ✓.\n\nSmall parts: bearing at (0.395,0.115): outer torus R0.0085 r0.0032 steel at z0.0032 axis Z; inner torus R0.0085? classic bearing: outer ring torus, inner ring torus R same? Use: outer cyl ring: torus R=0.0072 minor 0.0028; balls: 6 spheres r0.0022 at R0.0072 z0.0028; inner torus R0.0072? For simplicity: two tori (R0.0095 minor0.0025 outer; R0.0055 minor0.0022 inner) + 6 balls R0.0075 r0.0021. All at z≈0.0025-0.003. \nWasher: torus R0.0045 minor0.0016 at (0.435,0.075,0.0016).\n\nAlso maybe a small hex driver tool? skip.\n\nObject (target): name \"TargetPart\":\npuck cyl r0.020 d0.006 z0.003 alu bevel0.0015\nring groove accent: torus R0.0175 r0.0012 at z0.006 orange\nneck cyl r0.0115 d0.014 z0.013 alu\nhead cyl r0.013 d0.016 z0.028 alu bevel0.004\nhead torus accent R0.0128 r0.0014 z0.024\nhex socket dark cyl r0.004 d0.002 z0.0365 verts6 (half-embedded in head top z0.036: spans 0.0355..0.0375 proud 0.0005 — reads as insert? make depth 0.0015 at z0.0362 → top 0.0369 slight proud acceptable as socket cap. Or darker disc flush. fine.\n\nDesk: box dims(1.6,0.95,0.045) loc(0.18,0.02,-0.0225) bevel0.012 mat_desk. spans x -0.62..0.98, y -0.455..0.495. base at origin ✓ controller (-0.2,-0.13) ✓ object 0.469 ✓ bearing (0.395,0.115) ✓.\nLegs: panels dims(0.05,0.85,0.755) loc(-0.48,0.02,-0.4225) and (0.84,0.02,-0.4225) bevel0.008 mat dark? legs matte light gray alu? Use dark alu for contrast. Floor z=-0.80: legs from -0.045..-0.80 ✓.\nFloor/cove mesh as planned, mat_floor.\nAlso desk rear edge cable? no.\n\nCheck camera sees desk front edge: desk y front -0.455; camera y -1.32 → sees edge + floor below ✓ nice depth.\n\nCove: mat_floor same.\n\nNow lights + camera + world.\n\nCamera loc (0.98,-1.32,0.60) — check frame width at target dist 1.6: 0.99m. Scene x range -0.25(controller)..0.55(gripper+object 0.49) → 0.8 ✓. Vertical: elbow top 0.39 + gearbox? E.z+ r ~0.39; desk front bottom edge... fits.\n\nActually consider lens 65 → frame 0.885 wide; content 0.8 → tight-ish margins; use 60mm → 0.96. Keep 60.\n\nDOF focus at (0.36,0,0.14) fstop 7.\n\nLight energies with AgX: key 800W area size 0.9 at (0.5,-1.0,1.6); rim 650 at (0.7,1.1,1.4) size 0.6; fill 280 at (-1.1,-0.6,0.7) size 0.8 color cool; top 450 at (0.1,0.3,2.3) size 1.0. World strength 0.35.\n\nShould be well-lit.\n\nNow, potential issue: `bpy.ops.object.transform_apply` in box() changes context; ensure object active: after primitive_cube_add it is. ✓\n\nFor `cyl` smooth: caps are single n-gons (end_fill_type='NGON' default) ✓ len>4.\n\nBevel modifier on cylinders with smooth sides: bevel faces inherit smooth? Result typically fine.\n\nModifiers count high but ok.\n\nGLB export will apply modifiers — skin already applied; subsurf applied by exporter (it applies). Solidify applied ✓. Bevels applied ✓. Curves → exporter converts? glTF exporter exports curves as meshes (it converts bevelled curves? I believe exporter handles curves by converting to mesh). The benchmark handles it; fine.\n\nAlso set viewport display colors? not needed.\n\nAdd empty for camera target & DOF.\n\nNames via helper counters to keep unique (bpy auto-uniquifies anyway).\n\nAlso, \"visible rotating platform\" — turret + top plate with bolts reads as such; accent seam ring emphasizes rotation joint ✓. Maybe add rotation index marks: tiny notch box on turret side + tick on ring: add small dark box (0.004,0.002,0.010) at turret front (0,-0.0495,0.076)? that's where LED... put index mark at (0.03,-0.04,0.076)? skip, LED enough.\n\nNow write the membrane normal: ±v — choose +v (back) or -v? irrelevant; use v*1.\n\nFor strut1: membrane bays [3,8]; strut2 bay [4].\n\nPanel corners: tops[i], tops[i+1], bots[i+1], bots[i].\n\nAlso X-bay: middle bay gets both diagonals.\n\nEdge list build carefully with vertex indices: verts order: for i: top then bottom appended → top_i=2i, bot_i=2i+1.\n\nEdges: rails (2i,2i+2),(2i+1,2i+3); ends (0,1),(2n,2n+1); diagonals per parity; X extra.\n\nRadii list per vertex.\n\nbend: strut1 bend=-0.012 (toward -w1 → down-forward bow ✓); strut2 bend=-0.010.\n\nAlso depth profile prof uses |cos(pi t)|**0.75: at t=0: 1.15; t=0.5: 0.6. Wait 0.6+0.55*0=0.6 min ✓.\n\nh(t) = (dA+(dB-dA)t)/2 * prof(t).\n\nrad(t) = (rA+(rB-rA)t)*(1.30-0.5*sin(pi t)).\n\nStrut1: rA 0.0115→ ends 0.01495, mid 0.008*0.8? mid t0.5: base ~0.01*(0.8)=0.008. Depth ends: 0.080/2*1.15=0.046; mid 0.068/2*0.6=0.0204. Beam span 0.226: slender organic ✓.\n\nCheck strut1 doesn't intersect cheeks: near t=0 strut at A1+0.036 +... cheeks at y±0.036 inner; strut in v=0 plane ✓ no.\n\nStrut1 bottom rail near t=0 at -w1*0.046 → point A + (-w1)*0.046: A=(0.0268,0,0.1891) + (0.0308,0,-0.0342)=(0.0576,0,0.1549). Clear of turret (r0.05, top 0.102) ✓ clear of cheeks (y±0.036..0.050) ✓ v=0 plane ✓.\n\nOK.\n\nSkin root vertex: mark vertex 0.\n\nSubsurf render_levels 2.\n\nOne more: materials for strut: titanium with subtle anisotropic? Principled 'Anisotropic IOR Level'? input name 'Anisotropic IOR Level' in 4.x+. Set 0.3? risky name; use bs.inputs.get('Anisotropic IOR Level'). skip.\n\nFinal scene stats fine.\n\nAlso add bevel to membrane? no.\n\nAdd bevel to finger plates etc via box bevel param ✓.\n\nLet me also consider making link1 slightly darker tint vs link2? Both titanium same ✓.\n\nAccent rings also at wrist roll and base — consistent design language ✓.\n\nWrite the code now. Also include a ground-contact shadow? Cycles handles.\n\nAlso maybe set `scene.render.film_transparent=False` default ✓.\n\nSave file at end try/except.\n\nAlso, ensure `bpy.context.collection` valid — use scene.collection children: use `bpy.context.scene.collection.objects.link(ob)`? Use a dedicated collection: `col=bpy.data.collections.new('RobotArm'); scene.collection.children.link(col)` and link objects to col. For ops-created primitives they go to context collection (default Collection). Mixed fine. For non-ops (strut, membrane, cable), link to scene collection: `bpy.context.scene.collection.objects.link(ob)`? scene.collection is master; objects.link works on Collection. Yes.\n\nLet me finalize cable helper:\n\n```python\ndef cable(name, pts, r, mat):\n    cu=bpy.data.curves.new(name,'CURVE'); cu.dimensions='3D'\n    cu.resolution_u=12; cu.bevel_depth=r; cu.bevel_resolution=3; cu.resolution_u=16\n    sp=cu.splines.new('BEZIER'); sp.bezier_points.add(len(pts)-1)\n    for bp,co in zip(sp.bezier_points,pts):\n        bp.co=co; bp.handle_left_type='AUTO'; bp.handle_right_type='AUTO'\n    ob=bpy.data.objects.new(name,cu); bpy.context.scene.collection.objects.link(ob)\n    ob.data.materials.append(mat)\n    return ob\n```\n\nLook-at helper.\n\nLight helper:\n\n```python\ndef area_light(name, loc, energy, size, target, color=(1,1,1), shape='DISK'):\n    ld=bpy.data.lights.new(name,'AREA'); ld.energy=energy; ld.color=color; ld.shape=shape; ld.size=size\n    ob=bpy.data.objects.new(name,ld); scene.collection.objects.link(ob); ob.location=loc\n    look_at(ob,target)\n    return ob\n```\n\nWorld:\n\n```python\nw=bpy.data.worlds.new('Studio'); scene.world=w; w.use_nodes=True\nbg=w.node_tree.nodes['Background']; bg.inputs['Color'].default_value=(0.62,0.63,0.67,1); bg.inputs['Strength'].default_value=0.35\n```\n\nCamera:\n\n```python\ncd=bpy.data.cameras.new('Cam'); cd.lens=60; cd.sensor_width=36\ncam=bpy.data.objects.new('Camera',cd); scene.collection.objects.link(cam)\ncam.location=(0.98,-1.32,0.60); look_at(cam,(0.20,0.02,0.17))\ncd.dof.use_dof=True; cd.dof.aperture_fstop=7.0\nfocus=empty at (0.37,0,0.15); cd.dof.focus_object=focus\nscene.camera=cam\n```\n\nEmpty: `bpy.data.objects.new('Focus',None)`.\n\nAlso slight camera roll? no.\n\nNow, is 0.6m frame height enough at target for full arm? Arm top 0.39 vs target z0.17: +0.22; frame half-height 0.48 ✓. Desk front bottom edge: point (0.18,-0.455,-0.045): relative to cam... it'll be in lower frame ✓.\n\nOne more check — the benchmark renders orbit around scene; floor cove covers y to -3? cove floor part from y=-3.0 to 1.0 then curves up. Camera orbit radius maybe ~1.5-2 → stays on floor ✓. Cove width x ±3.5 ✓.\n\nCove mesh:\n\n```python\nprof=[(-3.0,-0.80),(1.0,-0.80)]\nimport math\nfor k in range(1,10):\n    a=pi/2*k/9\n    prof.append((1.0+0.9*sin(a), -0.80+0.9*(1-cos(a))))\nprof.append((1.9,3.0))\nxs=[-3.5,3.5]\nverts=[(x,y,z) for y,z in prof for x in xs]  # careful ordering\nfaces: for i in range(len(prof)-1): quad (i*2, i*2+1, i*2+3, i*2+2)\n```\nNormal orientation: facing -y/-z toward camera region. Double-sided render default in Cycles ✓.\n\nSolidify modifier thickness 0.05 offset 0.\n\nDesk legs also visible in orbit ✓.\n\nAlright, also add slight bevel to desk via bevel modifier ✓.\n\nPotential z-fighting: grommets half-embedded fine.\n\nTime to also double check `primitive_cylinder_add` param name `vertices` ✓, `radius`,`depth` ✓.\n\n`primitive_torus_add`: parameters major_radius/minor_radius exist with mode default 'MAJOR_MINOR'? In Blender 4.x+, operator params: mode ('MAJOR_MINOR'), abso_major_rad, abso_minor_rad, major_radius, minor_radius... I recall major_radius & minor_radius work with mode MAJOR_MINOR (relative) — yes standard usage `bpy.ops.mesh.primitive_torus_add(major_radius=R, minor_radius=r)` common. ✓\n\nSkin: after `me.from_pydata`, adding SKIN modifier — need `bpy.context.view_layer.update()` before accessing skin_vertices? Common script pattern:\n\n```python\nmod = obj.modifiers.new('','SKIN')\nme.skin_vertices[0].data[0].radius = ...\n```\nworks without update generally. I'll include update anyway.\n\nmodifier_apply: ensure object selected & active:\n```python\nbpy.ops.object.select_all(action='DESELECT')\nob.select_set(True); bpy.context.view_layer.objects.active=ob\nbpy.ops.object.modifier_apply(modifier=mod.name)\n```\n\nThen shade smooth & subsurf.\n\nI think we're ready. Also add \"Subsurf\" only render? viewport levels 2 ok.\n\nMembrane material side: transmission with thickness — set `m.surface_render_method`? In 4.2+, for alpha blend there's surface_render_method ('DITHERED'/'BLENDED')? Not needed for transmission.\n\nIOR 1.38, transmission 0.9, roughness 0.35, base color (0.72,0.78,0.82), metallic 0, coat 0.25.\n\nPads mat: (0.85,0.38,0.06) rough 0.55 metallic 0.0.\n\nAccent mat: (0.80,0.25,0.04) metallic 0.85 rough 0.3.\n\nCheck LED emissive visible at 64 samples small size — yes bright points.\n\nAlso I want a subtle bevel on every cyl: default bevel=0.0015 for >0.01 r. I'll pass per-call.\n\nNow assemble full code. Also include comments. Ensure no syntax errors, no undefined vars. Let me write it mentally clean.\n\nAlso caution: `Matrix((x,y,z)).transposed()` — Matrix rows from vectors; transposed gives columns = x,y,z ✓.\n\nlook_at:\n\n```python\ndef look_at(ob, target):\n    d=Vector(target)-ob.location\n    ob.rotation_euler=d.to_track_quat('-Z','Y').to_euler()\n```\n\nFor cylinders I use set_frame which sets matrix_world — overrides rotation entirely ✓.\n\nFor boxes with frame param: pass (x,y,z) tuple.\n\nWrite micro helpers for repeated joint builds to reduce code? I'll write inline but concise.\n\nAlso add `import bpy` etc.\n\nEdge: `bpy.ops.object.transform_apply` poll needs object mode ✓ headless default.\n\nNumber formatting fine.\n\nLet me also double check fork plates frame: box with frame (u1,v,w1) where v=Y — dims map (x→u1 dim0.052, y→v 0.010, z→w1 0.046) ✓.\n\nCheek plates: plain axis-aligned boxes (frame None).\n\nOne risk: too many modifiers (bevels) slow GLB export — acceptable.\n\nAlso set each object's `data.materials` before modifiers fine.\n\nFinally set scene frame? not needed.\n\nAlso name the file save: \n\n```python\ntry:\n    bpy.ops.wm.save_as_mainfile(filepath=bpy.path.abspath('//robot_arm_studio.blend'))\nexcept Exception as e:\n    print('save failed', e)\n```\n\nPrint done.\n\nLet me also add a few tick marks / rotation indicator: small orange box on turret: (0.0,-0.0492,0.082) dims (0.006,0.0015,0.008)? LED at z0.076 y-0.0505... LED bezel dark r0.0035 at (0,-0.0495,0.072), led core r0.0022 at y-0.0508. Add orange tick at (0,-0.0498,0.085) dims(0.005,0.0012,0.006) accent ✓ rotation index.\n\nAlso add a couple of small screw heads on cheek outer faces near bottom: 2 bolts per cheek axis ±Y at (±? cheeks y outer ±0.050: bolt at (-0.02, ±0.0505, 0.12) axis Y r0.0028. Add.\n\nOK writing final code. I'll be careful with the strut dict return:\n\n```python\ndef optimized_strut(name,A,B,dA,dB,rA,rB,bend,n,mat,xbrace=True):\n    ...\n    return {'obj':ob,'tops':topsP,'bots':botsP,'u':u,'v':v,'w':w,'A':A,'B':B,'L':L,'h':hfun,'rad':rfun}\n```\ntopsP/botsP lists of Vector positions.\n\nClips:\n\n```python\ndef cable_clip(name, strut, t, cable_off, mat):\n    u=strut['u']; v=strut['v']; w=strut['w']; A=strut['A']; L=strut['L']\n    cl=A+u*(L*t)+ w*(0)  # centerline without bend? include bend: strut center C included bend; recompute:\n```\nStore bend in dict; center(t)=A+u*(L t)+w*(bend sin(pi t)). surface = h(t)+rad(t). clip spans from surface-0.004 to cable_off+0.004: depth=(cable_off - surface)+0.010; center offset = surface + depth/2 - 0.004?? Let me: inner end at surface-0.003 (embedded slightly into beam region... beam surface at `surface` from centerline; clip from surface-0.002 to cable_off+0.002: depth = cable_off+0.002-(surface-0.002) = cable_off-surface+0.004; center off = (surface-0.002 + cable_off+0.002)/2 = (surface+cable_off)/2.\ndims: (0.012 along u, 0.020 along v, depth along w). loc = center(t) - w*center_off (cable on -w side). frame (u,v,w). mat dark.\n\nCable offsets: link1 cable_off=0.072; link2 0.050.\n\nCable point function: pt(t, voff) = center(t) - w*cable_off + v*voff.\n\nGood. Now strut2 L = (B2-A2).length etc — all within function.\n\nAlso membrane from strut dict: bays indexes within n.\n\nWrite everything. Also second small membrane on strut1 bay 8 normal -v? same.\n\nAlso I realize pin at shoulder `cyl r0.0105 d0.17` spans y ±0.085 — ends near collars ✓.\n\nAlso shoulder motor flange at y=-0.053 overlaps cheek outer (0.050) ✓.\n\nGearbox y0.063 spans 0.050..0.076 ✓ from cheek outer face.\n\nElbow gearbox at y 0.046 spans 0.037..0.055; fork outer 0.035 — small gap 0.002: fine add flange r0.024 d0.004 at y0.036.\n\nEncoder cap wrist y0.024 spans 0.018..0.030: fork outer 0.026 → overlaps fork plate (0.018..0.026)?? fork plate y center ±0.022 dim 0.008 → spans 0.018..0.026. Encoder 0.018..0.030 intersects fork plate region at W — but encoder is AT W (axis center) where pin/block are; fork plate is around W too (plate spans u W-0.029..W+0.017 at y 0.018..0.026). Encoder cylinder r0.0135 at y0.018..0.030 → overlaps fork plate y0.018..0.026 region. Physically encoder mounts ON fork outer face (0.026): shift encoder to y center 0.032 spans 0.026..0.038 ✓, cap y0.0405, collar y0.044. Motor wrist: flange at y-0.027, housing y-0.043 spans -0.028..-0.058, cap -0.060, LED -0.063. fork outer -0.026 ✓ flange -0.025..-0.029 ok.\n\nSimilarly elbow gearbox: fork outer 0.035 → flange y0.0365 spans 0.0345..0.0385, housing y0.049 spans 0.039..0.059, cap y0.062, collar y0.066, hex y0.069. Motor elbow: flange -0.0365, housing y-0.052 spans -0.0375..-0.0665? depth0.028: y-0.052±0.014 → -0.038..-0.066; cap -0.0685; collar -0.072; LED -0.075. Adjust cable endpoints: c2 end (E.x,-0.070,E.z+0.006)? motor cap at -0.0685: end (E.x,-0.069,E.z+0.004). c3 start (E.x+0.003,-0.069,E.z+0.008)?? start near cap top. ok.\n\nShoulder: cheeks outer ±0.050. Gearbox(+Y): flange y0.0515 d0.003, housing y0.0645 d0.024 spans 0.0525..0.0765 r0.032, cap y0.080 d0.007 r0.020, collar y0.0855 r0.013, hex y0.088. Motor(-Y): flange y-0.0515, housing y-0.077 d0.048 spans -0.053..-0.101 r0.024, cap y-0.104, collar y-0.1085, hex -0.111. Pin d0.19 spans ±0.095 ends inside cap/collar zones ✓. c1 start (0,-0.107,0.156).\n\nWrist block between forks: v ±0.017 vs fork inner ±0.018 ✓.\n\nRoll actuator r0.0145 vs wrist fork plates at y±0.018..0.026: actuator at v=0 plane ✓ no clash; but actuator cylinder extends back to W+u3*0.002 → near block ✓.\n\nCheck roll actuator vs link2 fork plates: plates extend u2 to W+0.017 at y±0.018..0.026, w extent ±0.017 around... plates are boxes dims (0.046,0.008,0.034) in frame(u2,v,w2) centered W-u2*0.006 → w2 extent ±0.017. Actuator along u3 = u2 rotated -28° about v: from W going +u3. Does actuator (r0.0145) hit plates? Plates occupy y 0.018..0.026 & -0.026..-0.018; actuator radius in v = 0.0145 < 0.018 ✓ clears.\n\nWrist rotation: block r0.016 rotates between forks ✓ clearance 0.001 ✓.\n\nGripper body at s0.047.. vs fork plates end u2 W+0.017: body center along u3 from W: W+u3*0.065; nearest body point to W: s0.047 at v0: fine.\n\nNow confirm gripper body doesn't hit desk: lowest body point: s0.047 z = 0.165-0.9553*0.047=0.1201 minus w3/z extents ~0.02 → ~0.10 ✓.\n\nFingertips z 0.041 ✓.\n\nAll good. Also object at (0.4687, 0): on desk ✓ within desk x range ✓.\n\nCamera target maybe (0.22,0,0.18). Fine-tune: set target (0.21,0.0,0.18).\n\nAlso add subtle floor shadow catcher? cycles shadows natural.\n\nLet me write the code now in full. I'll be meticulous with syntax.\n\nAlso remember: after all building, `bpy.context.view_layer.update()`.\n\nOne more consideration: benchmark GLB includes \"contestant camera\" ✓ scene.camera set.\n\nAlso for orbit render, lighting works all around? Rim from +Y back; orbit from behind gets some light from rim/top ✓ plus world ambient 0.35 ✓.\n\nWrite code:\n\n```python\nimport bpy, math\nfrom math import sin, cos, pi, radians, atan2\nfrom mathutils import Vector, Matrix\n\nscene = bpy.context.scene\n# wipe\nbpy.ops.object.select_all(action='SELECT')\nbpy.ops.object.delete(use_global=False)\n\n# render setup...\n```\n\nThen materials, helpers, build.\n\nI'll now write out fully, keeping track of every variable.\n\nFor mats:\n```\ntitanium = mat_principled('Strut_Titanium',(0.60,0.61,0.64),1.0,0.34)\nalu = mat_principled('Alu',(0.78,0.79,0.81),1.0,0.22)\nalu_dark = mat_principled('AluDark',(0.15,0.16,0.18),0.9,0.32)\nsteel = mat_principled('Steel',(0.42,0.43,0.46),1.0,0.18)\naccent = mat_principled('Accent',(0.82,0.26,0.045),0.85,0.30)\ncablem = mat_principled('Cable',(0.012,0.013,0.015),0.0,0.55)\npadm = mat_principled('Pad',(0.85,0.38,0.06),0.0,0.5)\ndeskm = mat_principled('Desk',(0.80,0.79,0.76),0.0,0.38)\nfloorm = mat_principled('Floor',(0.66,0.66,0.68),0.0,0.55)\nboxm = mat_principled('Controller',(0.05,0.05,0.06),0.3,0.42)\nledg = mat_principled('LEDG',(0.02,0.08,0.03),0,0.4, emission=(0.15,1.0,0.35), estr=8)\nleda = mat_principled('LEDA',(0.08,0.04,0.01),0,0.4, emission=(1.0,0.5,0.1), estr=8)\nmemb = membrane material with noise\n```\n\nmembrane mat function with noise — inline.\n\nLet me write the entire script.\n\nAlso add tiny bolts on gripper finger roots? pivot pins exist ✓.\n\nAlso small gusset: link between carriage and finger root — finger plate overlaps carriage ✓.\n\nAlso add two screws on each finger plate outer face holding pad? pads have no visible fasteners — add micro bolt on pad outer? Pads outer face covered by plate (pad between plate inner? pad mounted on inner face). Add 2 micro bolts through plate into pad on outer face at pad location: bolts axis v at plate outer faces y=±(0.017+0.00225)=±0.01925 at s0.120/0.128 w3±0.003. Simple: two bolts per plate: positions W+u3*s ± w3*0.003 + v*(±0.0193), axis v (outward). r0.0016 h0.002 steel. Adds \"replaceable pads\" believability ✓.\n\nbolt() places washer+head from surface point along axis: pass p at surface, axis outward (0,±1,0).\n\nNow finalize quantities & write.\n\nFor the cove normals & smooth: set polys smooth? flat is fine; with smooth shading profile curve smooths: set smooth True for all → the flat floor part would try smooth with wall across edge? Subsurf not used; smooth shading on quads interpolates normals — floor to curve transition would shade oddly at the seam vertex but since curve dense it's fine; flat also fine. Use smooth.\n\nAlso floor mat: give slight roughness 0.6.\n\nAlso may add contact shadow strengthening via light? skip.\n\nWrite code — also include a second tiny detail: desk has a faint groove? skip.\n\nAlso the \"small machined object\" described ✓.\n\nCheck total strut node count: strut1 n=12 → 26 verts; skin apply → mesh ~ (26*8?) fine.\n\nNow produce final answer code. Careful with:\n\n- `me.skin_vertices[0].data` after adding modifier & update.\n- When applying modifier, object must be in view layer & active ✓.\n- After apply, polys exist.\n\nFor membranes, `from_pydata(verts, [], faces)` ✓.\n\nAlso create cable curves — GLB may or may not include; benchmark handles conversion best-effort.\n\nLet me also ensure I don't shadow builtin names.\n\nTime to write. I'll aim for clarity & correctness over brevity.\n\nOne more check: `bpy.ops.mesh.primitive_torus_add` minor_segments param name `minor_segments` ✓ major_segments ✓.\n\nLED helper:\n\n```python\ndef led(name, p, axis, mat, r=0.0022):\n    a=Vector(axis).normalized()\n    cyl(name+'_bz', r*1.7, 0.0018, Vector(p)-a*0.0005, axis, alu_dark, verts=24, bevel=0)\n    cyl(name+'_c', r, 0.0012, Vector(p)+a*0.0008, axis, mat, verts=16, bevel=0)\n```\n\nFine.\n\nCyl default verts 48 for big parts; small use 24.\n\nNow writing the code end-to-end.\n\ndef rod(p1,p2,r,mat,name,verts=12): d=Vector(p2)-Vector(p1); cyl(name, r, d.length, (Vector(p1)+Vector(p2))/2, axis=d.normalized(), mat=mat, verts=verts, bevel=0, smooth=True)\n\nBut cyl signature order — define cyl(name, r, depth, loc, axis, mat, verts, bevel, smooth).\n\nAlso box(frame=None).\n\nAlso note: when passing axis to cyl with default (0,0,1) frame_from_axis gives identity-ish: z=(0,0,1), t=(0,0,1)? abs(z.z)=1 → t=(1,0,0): x=z×t=(0,1,0)? z×t = (0,0,1)×(1,0,0) = (0*0-1*0, 1*1-0*0, 0-0)=(0,1,0); y=z×x=(0,0,1)×(0,1,0)=(-1,0,0). Matrix columns x=(0,1,0),y=(-1,0,0),z=(0,0,1) det=+1 ✓ fine (rotated 90° about Z, irrelevant for cylinders).\n\nBolt heads verts=6 rotation arbitrary ✓.\n\nNow, strut function code:\n\n```python\ndef optimized_strut(name, A, B, dA, dB, rA, rB, bend, n, mat):\n    A=Vector(A); B=Vector(B)\n    u=(B-A); L=u.length; u.normalize()\n    v=Vector((0.0,1.0,0.0))\n    w=u.cross(v).normalized()\n    v=w.cross(u).normalized()\n    def prof(t): return 0.60+0.55*(abs(cos(pi*t))**0.75)\n    def hfun(t): return (dA+(dB-dA)*t)*0.5*prof(t)\n    def rfun(t): return (rA+(rB-rA)*t)*(1.30-0.50*sin(pi*t))\n    def center(t): return A+u*(L*t)+w*(bend*sin(pi*t))\n    verts=[]; edges=[]\n    for i in range(n+1):\n        t=i/n; C=center(t); h=hfun(t)\n        verts.append(C+w*h); verts.append(C-w*h)\n    for i in range(n):\n        a=2*i\n        edges.append((a,a+2)); edges.append((a+1,a+3))\n    edges.append((0,1)); edges.append((2*n,2*n+1))\n    diag=set()\n    for i in range(n):\n        a=2*i\n        if i%2==0: diag.add((a,a+3))\n        else: diag.add((a+1,a+2))\n    mid=n//2; a=2*mid\n    diag.add((a,a+3)); diag.add((a+1,a+2))\n    for e in diag:\n        edges.append((min(e),max(e)))\n    radii=[]\n    for i in range(n+1):\n        r=rfun(i/n); radii += [r,r]\n    me=bpy.data.meshes.new(name)\n    me.from_pydata([tuple(p) for p in verts], edges, [])\n    ob=bpy.data.objects.new(name,me)\n    bpy.context.scene.collection.objects.link(ob)\n    sk=ob.modifiers.new('Skin','SKIN')\n    bpy.context.view_layer.update()\n    sv=me.skin_vertices[0].data\n    for i,d in enumerate(sv): d.radius=(radii[i],radii[i])\n    sv[0].use_root=True\n    bpy.ops.object.select_all(action='DESELECT')\n    ob.select_set(True); bpy.context.view_layer.objects.active=ob\n    bpy.ops.object.modifier_apply(modifier=sk.name)\n    for p in me.polygons: p.use_smooth=True\n    sub=ob.modifiers.new('Sub','SUBSURF'); sub.levels=2; sub.render_levels=2\n    me.materials.append(mat)\n    tops=[verts[2*i] for i in range(n+1)]; bots=[verts[2*i+1] for i in range(n+1)]\n    return dict(obj=ob,u=u,v=v,w=w,A=A,L=L,n=n,tops=tops,bots=bots,center=center,hfun=hfun,rfun=rfun)\n```\n\nWait diag edges (a, a+3): top_i to bot_{i+1}: indices top_i=2i, bot_{i+1}=2(i+1)+1=2i+3 ✓. (a+1,a+2): bot_i to top_{i+1} ✓.\n\nX at mid adds both diagonals — one may duplicate existing: set handles.\n\nDuplicate rail/edge none.\n\nMembrane:\n\n```python\ndef membrane(name, strut, bay, mat, bow=0.0028):\n    tops=strut['tops']; bots=strut['bots']; nrm=strut['v']\n    c00=bots[bay]; c10=bots[bay+1]; c11=tops[bay+1]; c01=tops[bay]\n```\nOrder for consistent bilinear: P00=c00(bot i), P10=c10(bot i+1), P11=c11(top i+1), P01=c01(top i) ✓ quad loop faces as built.\n\n inset 0.07.\n\nClips:\n\n```python\ndef cable_clip(name, st, t, off, mat):\n    u=st['u']; v=st['v']; w=st['w']\n    C=st['center'](t); surf=st['hfun'](t)+st['rfun'](t)\n    depth=off-surf+0.006\n    loc=C-w*((surf+off)/2)\n    return box(name,(0.012,0.020,depth),loc,frame=(u,v,w),mat=mat,bevel=0.002)\n```\n\nCable point helper:\n\n```python\ndef strut_cable_pts(st, off, ts, voff):\n    return [st['center'](t)-st['w']*off+st['v']*voff for t in ts]\n```\n\nFull cable2 pts: [grommet pt] + pts at ts [0.12,0.3,0.55,0.78,0.9 with voff lerp] + end. For last segment voff transitions to motor y; simpler: build pts list manually:\n\n```python\npts=[(0.012,-0.026,0.104)]\npts+=strut_cable_pts(s1,0.072,[0.10,0.28,0.52,0.74],-0.026)\npts+=[Vector((E.x,-0.05,E.z))+... ]\n```\nend: (E.x, -0.069, E.z+0.004). Add mid transition pt: s1 center(0.92) - w1*0.06 + v*(-0.05).\n\nOk good enough; AUTO handles smooth.\n\nLet me write the final code block now. Also add `random`? not needed.\n\nDouble-check `mat_principled` emission inputs exist in 5.1: 'Emission Color','Emission Strength' ✓.\n\nCoat: 'Coat Weight' ✓.\n\nAlso desk: maybe two-tone: add thin darker edge band? skip.\n\nFinal: camera slight adjust: loc (1.00,-1.30,0.58), target (0.21,0.0,0.175), lens 60.\n\nAlso set `scene.render.resolution_percentage=100`.\n\nAlso transparent film? no.\n\nNow — write it all out carefully. I'll count on ~450 lines. Ensure no f-string issues, all Vector math with Vector().\n\nPotential pitfall: box() with frame passed — set_frame expects vectors; pass tuple of Vectors.\n\nIn bolt_ring, basis from frame_from_axis(axis) → x,y in plane ✓.\n\nFor micro bolts on collar faces: ring_r small.\n\nAlright, also verify thrust washers don't clash with hub cylinder at shoulder: washers r0.0135 at y±0.0305 z0.165 axis Y depth0.003: hub r0.026 → hub surface reaches y±0.026 at A1; washers between 0.026..0.036 ✓.\n\nElbow: eye box y ±0.018; washers ±0.0215 ✓ inner fork ±0.025 ✓.\n\nWrist: block v ±0.017; washers ±0.0175? fork inner ±0.018 → washer depth0.002 at y±0.0175 spans 0.0165..0.0185 overlaps both slightly — set y±0.0175 depth0.0015 → 0.01675..0.01825 slight overlap with block (0.017) — negligible/intentional press fit. Fine.\n\nNow code. Also after building everything, select none.\n\nOne more: \"no exposed corrugated pipes\" ✓ none.\n\nI'll write the script now.\n\nAlso: `scene.cycles.use_denoising=True` default fine.\n\nAlso possible: `scene.render.engine='CYCLES'` then benchmark overrides anyway.\n\nCheck `primitive_cube_add(size=1)` then dimensions then apply scale ✓.\n\nBevel width relative small dims: clamp width < min(dims)/2.5 — choose widths carefully per call.\n\nFor nameplate dims (0.05,0.002,0.010) bevel 0.0006.\n\nWriting final.\n\nAlso — include a faint large softbox reflection helper? Not needed with area lights (they reflect in metals ✓ premium).\n\nI think code is ready to write. Let me draft it completely in my head onto the answer, being careful.\n\nAlso: after creating many objects via ops, active object changes — box()'s transform_apply uses active ✓ since just created.\n\nEdge: `bpy.ops.object.transform_apply(location=False, rotation=False, scale=True)` with rotation set later via matrix — but I set location at creation then apply scale only; then set_frame sets full matrix ✓.\n\nFor boxes with frame, dimensions applied in local axes then framed ✓.\n\nTorus smooth: set all polys smooth.\n\nMaterials appended: `o.data.materials.append(mat)`.\n\nNow final answer.\n\nOne more check on membrane normals for Cycles transmission: double-sided ok.\n\nAnd GLB: solidify on membrane gives real thickness ✓.\n\nSave blend path: use `os.path.join(os.path.expanduser('~'), ...)`? Keep `bpy.path.abspath('//')` fallback tmp? Just try '//robotic_arm.blend' except pass. Actually if blend never saved, '//' resolves to cwd of process — fine.\n\nWrite it.","format":"unknown","index":0}]}}],"usage":{"prompt_tokens":1407,"completion_tokens":58760,"total_tokens":60167,"cost":0.885621,"is_byok":false,"prompt_tokens_details":{"cached_tokens":0,"cache_write_tokens":0,"audio_tokens":0,"video_tokens":0},"cost_details":{"upstream_inference_cost":0.885621,"upstream_inference_prompt_cost":0.004221,"upstream_inference_completions_cost":0.8814},"completion_tokens_details":{"reasoning_tokens":47906,"image_tokens":0,"audio_tokens":0}}}

```python
import bpy, math, os
from math import sin, cos, pi, radians, atan2
from mathutils import Vector, Matrix

# ============================================================
# SCENE RESET / RENDER SETUP
# ============================================================
bpy.ops.object.select_all(action='SELECT')
bpy.ops.object.delete(use_global=False)
scene = bpy.context.scene
scene.render.engine = 'CYCLES'
scene.cycles.samples = 64
scene.cycles.use_denoising = True
scene.render.resolution_x = 1536
scene.render.resolution_y = 1536
scene.render.resolution_percentage = 100
scene.render.image_settings.file_format = 'PNG'
scene.unit_settings.system = 'METRIC'
try:
    scene.view_settings.look = 'AgX - Medium High Contrast'
except Exception:
    pass

# ============================================================
# MATERIALS
# ============================================================
def mat_principled(name, color, metallic=0.0, rough=0.4, transmission=0.0,
                   ior=1.45, emission=None, estr=0.0, coat=0.0):
    m = bpy.data.materials.new(name); m.use_nodes = True
    bs = m.node_tree.nodes['Principled BSDF']
    bs.inputs['Base Color'].default_value = (*color, 1.0)
    bs.inputs['Metallic'].default_value = metallic
    bs.inputs['Roughness'].default_value = rough
    if transmission > 0:
        bs.inputs['Transmission Weight'].default_value = transmission
        bs.inputs['IOR'].default_value = ior
    if coat > 0:
        bs.inputs['Coat Weight'].default_value = coat
    if emission is not None:
        bs.inputs['Emission Color'].default_value = (*emission, 1.0)
        bs.inputs['Emission Strength'].default_value = estr
    return m

titanium = mat_principled('Strut_Titanium', (0.60, 0.61, 0.64), 1.0, 0.34)
alu      = mat_principled('Machined_Aluminum', (0.78, 0.79, 0.81), 1.0, 0.22)
alu_dark = mat_principled('Anodized_Dark', (0.15, 0.16, 0.18), 0.9, 0.32)
steel    = mat_principled('Steel', (0.42, 0.43, 0.46), 1.0, 0.18)
accent   = mat_principled('Accent_Orange', (0.82, 0.26, 0.045), 0.85, 0.30)
cablem   = mat_principled('Cable_Black', (0.012, 0.013, 0.015), 0.0, 0.55)
padm     = mat_principled('Pad_Urethane', (0.85, 0.38, 0.06), 0.0, 0.5)
deskm    = mat_principled('Desk_Laminate', (0.80, 0.79, 0.76), 0.0, 0.38)
floorm   = mat_principled('Studio_Floor', (0.66, 0.66, 0.68), 0.0, 0.58)
boxm     = mat_principled('Controller_Housing', (0.05, 0.05, 0.06), 0.3, 0.42)
ledg     = mat_principled('LED_Green', (0.02, 0.08, 0.03), 0, 0.4, emission=(0.15, 1.0, 0.35), estr=9.0)
leda     = mat_principled('LED_Amber', (0.08, 0.04, 0.01), 0, 0.4, emission=(1.0, 0.5, 0.1), estr=9.0)

# translucent technical membrane (clear reinforced film / TPU)
memb = mat_principled('Membrane_TPU', (0.72, 0.78, 0.82), 0.0, 0.34,
                      transmission=0.9, ior=1.38, coat=0.25)
_nt = memb.node_tree
_bs = _nt.nodes['Principled BSDF']
_noise = _nt.nodes.new('ShaderNodeTexNoise')
_noise.inputs['Scale'].default_value = 320.0
_noise.inputs['Detail'].default_value = 2.0
_bump = _nt.nodes.new('ShaderNodeBump')
_bump.inputs['Strength'].default_value = 0.12
_bump.inputs['Distance'].default_value = 0.00025
_nt.links.new(_noise.outputs['Fac'], _bump.inputs['Height'])
_nt.links.new(_bump.outputs['Normal'], _bs.inputs['Normal'])

# ============================================================
# GEOMETRY HELPERS
# ============================================================
def frame_from_axis(axis):
    z = Vector(axis).normalized()
    t = Vector((0, 0, 1)) if abs(z.z) < 0.95 else Vector((1, 0, 0))
    x = z.cross(t).normalized()
    y = z.cross(x).normalized()
    return x, y, z

def set_frame(obj, x, y, z, loc):
    M = Matrix((x, y, z)).transposed().to_4x4()
    M.translation = Vector(loc)
    obj.matrix_world = M

def assign(o, mat):
    if mat: o.data.materials.append(mat)

def cyl(name, r, depth, loc, axis=(0, 0, 1), mat=None, verts=48, bevel=0.0, smooth=True):
    bpy.ops.mesh.primitive_cylinder_add(vertices=verts, radius=r, depth=depth, location=loc)
    o = bpy.context.active_object; o.name = name
    x, y, z = frame_from_axis(axis)
    set_frame(o, x, y, z, loc)
    assign(o, mat)
    if smooth:
        for p in o.data.polygons:
            p.use_smooth = (len(p.vertices) == 4)
    if bevel > 0:
        m = o.modifiers.new('bev', 'BEVEL'); m.width = bevel; m.segments = 3; m.limit_method = 'ANGLE'
    return o

def box(name, dims, loc, frame=None, mat=None, bevel=0.0):
    bpy.ops.mesh.primitive_cube_add(size=1, location=loc)
    o = bpy.context.active_object; o.name = name
    o.dimensions = dims
    bpy.ops.object.transform_apply(location=False, rotation=False, scale=True)
    if frame:
        set_frame(o, frame[0], frame[1], frame[2], loc)
    assign(o, mat)
    if bevel > 0:
        m = o.modifiers.new('bev', 'BEVEL'); m.width = bevel; m.segments = 3; m.limit_method = 'ANGLE'
    return o

def torus(name, R, r, loc, axis=(0, 0, 1), mat=None):
    bpy.ops.mesh.primitive_torus_add(major_radius=R, minor_radius=r,
                                     major_segments=48, minor_segments=12, location=loc)
    o = bpy.context.active_object; o.name = name
    x, y, z = frame_from_axis(axis)
    set_frame(o, x, y, z, loc)
    assign(o, mat)
    for p in o.data.polygons: p.use_smooth = True
    return o

def bolt(name, p, axis, r, h, mat=steel, washer=True):
    a = Vector(axis).normalized(); P = Vector(p)
    if washer:
        cyl(name + '_w', r * 1.6, h * 0.30, P + a * (h * 0.15), axis, mat, verts=24)
    cyl(name + '_h', r, h, P + a * (h * 0.30 + h * 0.5), axis, mat, verts=6, smooth=False)

def bolt_ring(name, center, axis, ring_r, n, r, h, mat=steel, phase=0.0):
    x, y, z = frame_from_axis(axis)
    C = Vector(center)
    for k in range(n):
        a = phase + 2 * pi * k / n
        p = C + x * (ring_r * cos(a)) + y * (ring_r * sin(a))
        bolt('%s_%d' % (name, k), p, axis, r, h, mat, washer=False)

def rod(name, p1, p2, r, mat=steel, verts=12):
    d = Vector(p2) - Vector(p1)
    return cyl(name, r, d.length, (Vector(p1) + Vector(p2)) / 2, axis=d.normalized(),
               mat=mat, verts=verts)

def cable(name, pts, r, mat=cablem):
    cu = bpy.data.curves.new(name, 'CURVE'); cu.dimensions = '3D'
    cu.resolution_u = 16; cu.bevel_depth = r; cu.bevel_resolution = 3
    sp = cu.splines.new('BEZIER'); sp.bezier_points.add(len(pts) - 1)
    for bp, co in zip(sp.bezier_points, pts):
        bp.co = co; bp.handle_left_type = 'AUTO'; bp.handle_right_type = 'AUTO'
    ob = bpy.data.objects.new(name, cu)
    bpy.context.scene.collection.objects.link(ob)
    assign(ob, mat)
    return ob

def led(name, p, axis, mat, r=0.0022):
    a = Vector(axis).normalized(); P = Vector(p)
    cyl(name + '_bz', r * 1.7, 0.0018, P - a * 0.0004, axis, alu_dark, verts=24)
    cyl(name + '_c', r, 0.0014, P + a * 0.0009, axis, mat, verts=16)

def look_at(ob, target):
    d = Vector(target) - ob.location
    ob.rotation_euler = d.to_track_quat('-Z', 'Y').to_euler()

# ============================================================
# TOPOLOGY-OPTIMIZED STRUT BUILDER (skin + subsurf, organic)
# ============================================================
def optimized_strut(name, A, B, dA, dB, rA, rB, bend, n, mat):
    A = Vector(A); B = Vector(B)
    u = (B - A); L = u.length; u.normalize()
    v = Vector((0.0, 1.0, 0.0))
    w = u.cross(v).normalized()
    v = w.cross(u).normalized()
    def prof(t): return 0.60 + 0.55 * (abs(cos(pi * t)) ** 0.75)
    def hfun(t): return (dA + (dB - dA) * t) * 0.5 * prof(t)
    def rfun(t): return (rA + (rB - rA) * t) * (1.30 - 0.50 * sin(pi * t))
    def center(t): return A + u * (L * t) + w * (bend * sin(pi * t))
    verts = []; edges = []
    for i in range(n + 1):
        t = i / n; C = center(t); h = hfun(t)
        verts.append(C + w * h); verts.append(C - w * h)
    for i in range(n):
        a = 2 * i
        edges.append((a, a + 2)); edges.append((a + 1, a + 3))
    edges.append((0, 1)); edges.append((2 * n, 2 * n + 1))
    diag = set()
    for i in range(n):
        a = 2 * i
        diag.add((a, a + 3) if i % 2 == 0 else (a + 1, a + 2))
    mid = n // 2; a = 2 * mid
    diag.add((a, a + 3)); diag.add((a + 1, a + 2))   # X-braced middle bay
    for e in diag:
        edges.append((min(e), max(e)))
    radii = []
    for i in range(n + 1):
        r = rfun(i / n); radii += [r, r]
    me = bpy.data.meshes.new(name)
    me.from_pydata([tuple(p) for p in verts], edges, [])
    ob = bpy.data.objects.new(name, me)
    bpy.context.scene.collection.objects.link(ob)
    sk = ob.modifiers.new('Skin', 'SKIN')
    bpy.context.view_layer.update()
    sv = me.skin_vertices[0].data
    for i, d in enumerate(sv):
        d.radius = (radii[i], radii[i])
    sv[0].use_root = True
    bpy.ops.object.select_all(action='DESELECT')
    ob.select_set(True); bpy.context.view_layer.objects.active = ob
    bpy.ops.object.modifier_apply(modifier=sk.name)
    for p in me.polygons: p.use_smooth = True
    sub = ob.modifiers.new('Sub', 'SUBSURF'); sub.levels = 2; sub.render_levels = 2
    me.materials.append(mat)
    tops = [verts[2 * i] for i in range(n + 1)]
    bots = [verts[2 * i + 1] for i in range(n + 1)]
    return dict(obj=ob, u=u, v=v, w=w, A=A, L=L, n=n, tops=tops, bots=bots,
                center=center, hfun=hfun, rfun=rfun)

def membrane(name, st, bay, mat, bow=0.0028, nx=8, ny=8, inset=0.07):
    tops = st['tops']; bots = st['bots']; nrm = Vector(st['v'])
    c00 = bots[bay]; c10 = bots[bay + 1]; c11 = tops[bay + 1]; c01 = tops[bay]
    C = (c00 + c10 + c11 + c01) / 4
    P = [c + (C - c) * inset for c in (c00, c10, c11, c01)]
    verts = []; faces = []
    for j in range(ny + 1):
        s = j / ny
        for i in range(nx + 1):
            r = i / nx
            p = (1 - r) * (1 - s) * P[0] + r * (1 - s) * P[1] + r * s * P[2] + (1 - r) * s * P[3]
            p = p + nrm * (bow * sin(pi * r) * sin(pi * s))
            verts.append(tuple(p))
    for j in range(ny):
        for i in range(nx):
            a = j * (nx + 1) + i
            faces.append((a, a + 1, a + nx + 2, a + nx + 1))
    me = bpy.data.meshes.new(name)
    me.from_pydata(verts, [], faces)
    ob = bpy.data.objects.new(name, me)
    bpy.context.scene.collection.objects.link(ob)
    for p in me.polygons: p.use_smooth = True
    sol = ob.modifiers.new('Solid', 'SOLIDIFY'); sol.thickness = 0.0011; sol.offset = 0.0
    me.materials.append(mat)
    return ob

def cable_clip(name, st, t, off, mat=alu_dark):
    u = st['u']; v = st['v']; w = st['w']
    C = st['center'](t); surf = st['hfun'](t) + st['rfun'](t)
    depth = off - surf + 0.006
    loc = C - w * ((surf + off) / 2)
    return box(name, (0.012, 0.020, depth), loc, frame=(u, v, w), mat=mat, bevel=0.002)

def scpts(st, off, ts, voff):
    return [st['center'](t) - st['w'] * off + st['v'] * voff for t in ts]

# ============================================================
# KINEMATICS (joint layout)
# ============================================================
S = Vector((0.0, 0.0, 0.165))                       # shoulder (J2)
a1 = radians(48.0)
u1 = Vector((sin(a1), 0, cos(a1)))
L1 = 0.30
E = S + u1 * L1                                     # elbow (J3)
W = Vector((0.425, 0.0, 0.165))                     # wrist pitch (J4)
_d = W - E; L2 = _d.length; u2 = _d / L2
th2 = atan2(u2.z, u2.x); th3 = th2 - radians(28.0)
u3 = Vector((cos(th3), 0, sin(th3)))                # tool axis
v = Vector((0, 1, 0))
w1 = u1.cross(v).normalized()
w2 = u2.cross(v).normalized()
w3 = u3.cross(v).normalized()
F = W + u3 * 0.130                                  # fingertip reference
obj_x = F.x + u3.x * 0.018

# ============================================================
# BASE ASSEMBLY (J1 rotary platform)
# ============================================================
box('BasePlate', (0.17, 0.17, 0.014), (0, 0, 0.007), mat=alu_dark, bevel=0.008)
for sx in (-1, 1):
    for sy in (-1, 1):
        bolt('BaseBolt', (0.072 * sx, 0.072 * sy, 0.014), (0, 0, 1), 0.0045, 0.005)
cyl('BaseLower', 0.062, 0.032, (0, 0, 0.030), mat=alu, bevel=0.004)
cyl('BaseBearingRing', 0.056, 0.012, (0, 0, 0.052), mat=alu_dark, bevel=0.002)
cyl('BaseAccentRing', 0.0568, 0.0022, (0, 0, 0.0575), mat=accent)
cyl('Turret', 0.050, 0.036, (0, 0, 0.076), mat=alu, bevel=0.004)
cyl('TurretTopPlate', 0.055, 0.008, (0, 0, 0.098), mat=alu_dark, bevel=0.002)
bolt_ring('TurretBolt', (0, 0, 0.102), (0, 0, 1), 0.043, 6, 0.0028, 0.0035)
led('TurretLED', (0, -0.0495, 0.072), (0, -1, 0), ledg)
box('TurretTick', (0.005, 0.0014, 0.006), (0, -0.0498, 0.085), mat=accent, bevel=0.0005)
box('BaseNamePlate', (0.05, 0.002, 0.010), (0, -0.0856, 0.007), mat=alu, bevel=0.0006)
# shoulder cheeks
for s in (-1, 1):
    box('Cheek', (0.060, 0.014, 0.089), (-0.005, 0.043 * s, 0.1455), mat=alu, bevel=0.006)
    bolt('CheekBoltA', (-0.022, 0.0505 * s, 0.122), (0, s, 0), 0.0028, 0.0035, washer=False)
    bolt('CheekBoltB', (0.014, 0.0505 * s, 0.122), (0, s, 0), 0.0028, 0.0035, washer=False)
    bolt('CheekBoltC', (-0.022, 0.043 * s, 0.103), (0, 0, 1), 0.0025, 0.003, washer=False)
    box('StopTab', (0.014, 0.010, 0.018), (-0.032, 0.030 * s, 0.148), mat=alu_dark, bevel=0.002)
# J2 shaft / gearbox / motor
cyl('J2_Pin', 0.0105, 0.19, (0, 0, 0.165), axis=(0, 1, 0), mat=steel)
for s in (-1, 1):
    cyl('J2_Thrust', 0.0135, 0.003, (0, 0.0305 * s, 0.165), axis=(0, 1, 0), mat=steel)
cyl('J2_GearFlange', 0.034, 0.003, (0, 0.0515, 0.165), axis=(0, 1, 0), mat=alu_dark)
cyl('J2_Gearbox', 0.032, 0.024, (0, 0.0645, 0.165), axis=(0, 1, 0), mat=alu, bevel=0.004)
cyl('J2_GearCap', 0.020, 0.007, (0, 0.080, 0.165), axis=(0, 1, 0), mat=alu_dark, bevel=0.002)
cyl('J2_GearCollar', 0.013, 0.006, (0, 0.0855, 0.165), axis=(0, 1, 0), mat=steel)
bolt('J2_GearHex', (0, 0.0885, 0.165), (0, 1, 0), 0.0045, 0.004, washer=False)
bolt_ring('J2_GearBolt', (0, 0.077, 0.165), (0, 1, 0), 0.024, 4, 0.0022, 0.003)
cyl('J2_MotorFlange', 0.028, 0.005, (0, -0.053, 0.165), axis=(0, 1, 0), mat=alu_dark)
cyl('J2_Motor', 0.024, 0.048, (0, -0.077, 0.165), axis=(0, 1, 0), mat=alu, bevel=0.004)
cyl('J2_MotorCap', 0.0245, 0.006, (0, -0.104, 0.165), axis=(0, 1, 0), mat=alu_dark, bevel=0.002)
cyl('J2_MotorCollar', 0.011, 0.005, (0, -0.1085, 0.165), axis=(0, 1, 0), mat=steel)
torus('J2_AccentA', 0.0248, 0.0014, (0, -0.100, 0.165), axis=(0, 1, 0), mat=accent)

# ============================================================
# LINK 1 : hubs, fork, optimized strut
# ============================================================
cyl('L1_RootHub', 0.026, 0.062, S + u1 * 0.008, axis=u1, mat=alu, bevel=0.004)
cyl('L1_RootCollar', 0.029, 0.005, S + u1 * 0.040, axis=u1, mat=alu_dark)
bolt_ring('L1_RootBolt', S + u1 * 0.0435, u1, 0.021, 4, 0.002, 0.0028)
cyl('L1_EndCollar', 0.020, 0.050, E - u1 * 0.028, axis=u1, mat=alu, bevel=0.003)
bolt_ring('L1_EndBolt', E - u1 * 0.052, -u1, 0.014, 4, 0.0018, 0.0025)
for s in (-1, 1):
    box('L1_Fork', (0.052, 0.010, 0.046), E - u1 * 0.008 + v * (0.030 * s),
        frame=(u1, v, w1), mat=alu, bevel=0.005)
s1 = optimized_strut('Strut_Upper', S + u1 * 0.036, E - u1 * 0.040,
                     0.080, 0.056, 0.0115, 0.0085, -0.012, 12, titanium)
membrane('Memb_U1', s1, 3, memb)
membrane('Memb_U2', s1, 8, memb)

# ============================================================
# ELBOW JOINT (J3)
# ============================================================
cyl('J3_Pin', 0.007, 0.10, E, axis=(0, 1, 0), mat=steel)
for s in (-1, 1):
    cyl('J3_Thrust', 0.0105, 0.0025, E + v * (0.0215 * s), axis=(0, 1, 0), mat=steel)
cyl('J3_GearFlange', 0.024, 0.004, E + v * 0.0365, axis=(0, 1, 0), mat=alu_dark)
cyl('J3_Gearbox', 0.022, 0.020, E + v * 0.049, axis=(0, 1, 0), mat=alu, bevel=0.003)
cyl('J3_GearCap', 0.014, 0.006, E + v * 0.062, axis=(0, 1, 0), mat=alu_dark)
cyl('J3_GearCollar', 0.009, 0.005, E + v * 0.067, axis=(0, 1, 0), mat=steel)
bolt('J3_GearHex', E + v * 0.070, (0, 1, 0), 0.0035, 0.0035, washer=False)
bolt_ring('J3_GearBolt', E + v * 0.0595, (0, 1, 0), 0.016, 4, 0.0018, 0.0025)
cyl('J3_MotorFlange', 0.021, 0.004, E - v * 0.0365, axis=(0, 1, 0), mat=alu_dark)
cyl('J3_Motor', 0.019, 0.028, E - v * 0.052, axis=(0, 1, 0), mat=alu, bevel=0.003)
cyl('J3_MotorCap', 0.0195, 0.005, E - v * 0.0685, axis=(0, 1, 0), mat=alu_dark)
cyl('J3_MotorCollar', 0.009, 0.004, E - v * 0.0725, axis=(0, 1, 0), mat=steel)
led('J3_LED', E + Vector((0, -0.0718, 0.006)), (0, -1, 0), leda, r=0.0018)
torus('J3_Accent', 0.0198, 0.0012, E - v * 0.065, axis=(0, 1, 0), mat=accent)

# ============================================================
# LINK 2 : eye, optimized strut, end fork
# ============================================================
box('L2_RootEye', (0.056, 0.036, 0.040), E + u2 * 0.012, frame=(u2, v, w2), mat=alu, bevel=0.012)
cyl('L2_RootCollar', 0.0195, 0.006, E + u2 * 0.041, axis=u2, mat=alu_dark)
bolt_ring('L2_RootBolt', E + u2 * 0.0445, u2, 0.0135, 4, 0.0018, 0.0025)
cyl('L2_EndCollar', 0.015, 0.050, W - u2 * 0.028, axis=u2, mat=alu, bevel=0.003)
bolt_ring('L2_EndBolt', W - u2 * 0.052, -u2, 0.010, 4, 0.0015, 0.0022)
for s in (-1, 1):
    box('L2_Fork', (0.046, 0.008, 0.034), W - u2 * 0.006 + v * (0.022 * s),
        frame=(u2, v, w2), mat=alu, bevel=0.004)
s2 = optimized_strut('Strut_Fore', E + u2 * 0.038, W - u2 * 0.034,
                     0.052, 0.034, 0.0080, 0.0058, -0.010, 11, titanium)
membrane('Memb_F1', s2, 4, memb)

# ============================================================
# WRIST (J4 pitch + J5 roll) AND PARALLEL GRIPPER
# ============================================================
cyl('J4_Pin', 0.005, 0.072, W, axis=(0, 1, 0), mat=steel)
for s in (-1, 1):
    cyl('J4_Thrust', 0.0085, 0.0015, W + v * (0.0175 * s), axis=(0, 1, 0), mat=steel)
cyl('WristBlock', 0.016, 0.034, W, axis=(0, 1, 0), mat=alu, bevel=0.003)
cyl('J4_EncFlange', 0.0145, 0.003, W + v * 0.0275, axis=(0, 1, 0), mat=alu_dark)
cyl('J4_Encoder', 0.0135, 0.010, W + v * 0.033, axis=(0, 1, 0), mat=alu, bevel=0.002)
cyl('J4_EncCap', 0.010, 0.005, W + v * 0.0405, axis=(0, 1, 0), mat=alu_dark)
cyl('J4_EncCollar', 0.006, 0.004, W + v * 0.044, axis=(0, 1, 0), mat=steel)
cyl('J4_MotorFlange', 0.014, 0.003, W - v * 0.0275, axis=(0, 1, 0), mat=alu_dark)
cyl('J4_Motor', 0.0125, 0.028, W - v * 0.0425, axis=(0, 1, 0), mat=alu, bevel=0.002)
cyl('J4_MotorCap', 0.013, 0.005, W - v * 0.059, axis=(0, 1, 0), mat=alu_dark)
led('J4_LED', W + Vector((0, -0.0622, 0.004)), (0, -1, 0), ledg, r=0.0016)
# J5 roll actuator + tool flange
cyl('J5_Actuator', 0.0145, 0.034, W + u3 * 0.019, axis=u3, mat=alu, bevel=0.003)
torus('J5_Accent', 0.0148, 0.0016, W + u3 * 0.037, axis=u3, mat=accent)
cyl('ToolFlange', 0.019, 0.006, W + u3 * 0.041, axis=u3, mat=alu_dark, bevel=0.0015)
bolt_ring('ToolBolt', W + u3 * 0.0445, u3, 0.0135, 4, 0.002, 0.0028)
# gripper body
box('GripperBody', (0.036, 0.040, 0.024), W + u3 * 0.065, frame=(u3, v, w3), mat=alu_dark, bevel=0.005)
box('GripperFrontPlate', (0.004, 0.036, 0.020), W + u3 * 0.0845, frame=(u3, v, w3), mat=alu, bevel=0.001)
bolt_ring('GripPlateBolt', W + u3 * 0.0868, u3, 0.011, 4, 0.0016, 0.0022)
led('GripLED', W + u3 * 0.060 - v * 0.0206, (0, -1, 0), leda, r=0.0015)
# servo on top
cyl('GripServoFlange', 0.010, 0.003, W + u3 * 0.058 + w3 * 0.0125, axis=w3, mat=alu_dark)
cyl('GripServo', 0.0085, 0.018, W + u3 * 0.058 + w3 * 0.021, axis=w3, mat=alu, bevel=0.002)
cyl('GripServoCap', 0.0088, 0.004, W + u3 * 0.058 + w3 * 0.031, axis=w3, mat=alu_dark)
# rails + end plates
for s in (-1, 1):
    cyl('Rail', 0.0028, 0.045, W + u3 * 0.092 + w3 * (0.0065 * s), axis=(0, 1, 0), mat=steel, verts=20)
    box('RailEndPlate', (0.026, 0.004, 0.018), W + u3 * 0.092 + v * (0.0225 * s),
        frame=(u3, v, w3), mat=alu, bevel=0.002)
    # carriage, pivot, finger, pad
    box('Carriage', (0.014, 0.009, 0.016), W + u3 * 0.095 + v * (0.017 * s),
        frame=(u3, v, w3), mat=alu, bevel=0.002)
    cyl('FingerPivot', 0.0032, 0.012, W + u3 * 0.092 + v * (0.017 * s), axis=(0, 1, 0), mat=steel, verts=20)
    cyl('PivotCap', 0.0048, 0.0015, W + u3 * 0.092 + v * (0.0232 * s), axis=(0, 1, 0), mat=alu_dark, verts=20)
    box('Finger', (0.046, 0.0045, 0.012), W + u3 * 0.107 + v * (0.017 * s),
        frame=(u3, v, w3), mat=alu, bevel=0.0015)
    box('Pad', (0.012, 0.0030, 0.010), W + u3 * 0.124 + v * (0.01525 * s),
        frame=(u3, v, w3), mat=padm, bevel=0.001)
    for ds, dw in ((0.120, 0.003), (0.128, -0.003)):
        bolt('PadBolt', W + u3 * ds + w3 * dw + v * (0.0193 * s), (0, s, 0), 0.0016, 0.002, washer=False)
    rod('LinkRod', W + u3 * 0.058 + w3 * 0.0305,
        W + u3 * 0.100 + v * (0.017 * s) + w3 * 0.0075, 0.0016)

# ============================================================
# CONTROLLED CABLE ROUTING (slim black lines + clips)
# ============================================================
cyl('GrommetA', 0.005, 0.006, (-0.022, -0.033, 0.100), mat=alu_dark, verts=20)
cable('Cable_J2Motor', [(0, -0.107, 0.156), (-0.005, -0.094, 0.126),
                        (-0.014, -0.058, 0.106), (-0.022, -0.034, 0.102)], 0.0020)
cyl('GrommetB', 0.005, 0.006, (0.012, -0.026, 0.100), mat=alu_dark, verts=20)
pts = [(0.012, -0.026, 0.104)]
pts += scpts(s1, 0.072, [0.10, 0.28, 0.52, 0.74], -0.026)
pts += [s1['center'](0.92) - s1['w'] * 0.060 + s1['v'] * (-0.05),
        Vector((E.x, -0.069, E.z + 0.004))]
cable('Cable_Link1', pts, 0.0022)
for t in (0.28, 0.52, 0.74):
    cable_clip('Clip1', s1, t, 0.072)
pts = [Vector((E.x + 0.003, -0.069, E.z + 0.008))]
pts += scpts(s2, 0.050, [0.15, 0.40, 0.65, 0.88], -0.024)
pts += [Vector((W.x, -0.056, W.z + 0.004))]
cable('Cable_Link2', pts, 0.0020)
for t in (0.40, 0.70):
    cable_clip('Clip2', s2, t, 0.050)
cable('Cable_Servo', [W - v * 0.017 + w2 * 0.006,
                      W + u3 * 0.030 - v * 0.020 + w3 * 0.006,
                      W + u3 * 0.058 + w3 * 0.020 - v * 0.009], 0.0016)

# ============================================================
# TARGET OBJECT + SMALL DESK PARTS
# ============================================================
OX = Vector((obj_x, 0, 0))
cyl('Obj_Puck', 0.020, 0.006, OX + Vector((0, 0, 0.003)), mat=alu, bevel=0.0015)
torus('Obj_Ring', 0.0175, 0.0012, OX + Vector((0, 0, 0.006)), mat=accent)
cyl('Obj_Neck', 0.0115, 0.014, OX + Vector((0, 0, 0.013)), mat=alu, bevel=0.002)
cyl('Obj_Head', 0.013, 0.016, OX + Vector((0, 0, 0.028)), mat=alu, bevel=0.004)
torus('Obj_Ring2', 0.0128, 0.0014, OX + Vector((0, 0, 0.024)), mat=accent)
cyl('Obj_Socket', 0.004, 0.0015, OX + Vector((0, 0, 0.0362)), mat=alu_dark, verts=6, smooth=False)
# small bearing + washer nearby
BX = Vector((0.395, 0.115, 0))
torus('BearingOuter', 0.0095, 0.0026, BX + Vector((0, 0, 0.0032)), mat=steel)
torus('BearingInner', 0.0050, 0.0022, BX + Vector((0, 0, 0.0030)), mat=alu_dark)
for k in range(6):
    a = 2 * pi * k / 6
    cyl('Ball', 0.0021, 0.0042, BX + Vector((0.0074 * cos(a), 0.0074 * sin(a), 0.0031)),
        mat=steel, verts=16)
torus('Washer', 0.0045, 0.0016, (0.435, 0.075, 0.0016), mat=steel)

# ============================================================
# CONTROLLER BOX + DESK CABLE
# ============================================================
box('Controller', (0.10, 0.070, 0.032), (-0.20, -0.13, 0.016), mat=boxm, bevel=0.006)
box('ControllerLid', (0.090, 0.060, 0.003), (-0.20, -0.13, 0.0330), mat=alu_dark, bevel=0.001)
led('CtrlLED', (-0.175, -0.145, 0.0350), (0, 0, 1), ledg, r=0.0018)
cyl('CtrlGrommet', 0.0045, 0.005, (-0.149, -0.115, 0.014), axis=(1, 0, 0), mat=alu_dark, verts=20)
cyl('BaseGrommet', 0.005, 0.006, (0, -0.0605, 0.022), axis=(0, 1, 0), mat=alu_dark, verts=20)
cable('Cable_Desk', [(-0.146, -0.115, 0.014), (-0.10, -0.105, 0.005), (-0.05, -0.085, 0.004),
                     (-0.015, -0.070, 0.005), (0.0, -0.062, 0.018)], 0.0022)

# ============================================================
# DESK, LEGS, STUDIO COVE
# ============================================================
box('Desk', (1.6, 0.95, 0.045), (0.18, 0.02, -0.0225), mat=deskm, bevel=0.012)
for lx in (-0.48, 0.84):
    box('DeskLeg', (0.05, 0.85, 0.755), (lx, 0.02, -0.4225), mat=alu_dark, bevel=0.008)
prof = [(-3.0, -0.80), (1.0, -0.80)]
for k in range(1, 10):
    a = pi / 2 * k / 9
    prof.append((1.0 + 0.9 * sin(a), -0.80 + 0.9 * (1 - cos(a))))
prof.append((1.9, 3.0))
cverts = [(x, y, z) for (y, z) in prof for x in (-3.5, 3.5)]
cfaces = [(2 * i, 2 * i + 1, 2 * i + 3, 2 * i + 2) for i in range(len(prof) - 1)]
cme = bpy.data.meshes.new('Cove')
cme.from_pydata(cverts, [], cfaces)
cove = bpy.data.objects.new('StudioCove', cme)
bpy.context.scene.collection.objects.link(cove)
for p in cme.polygons: p.use_smooth = True
cme.materials.append(floorm)
sol = cove.modifiers.new('Solid', 'SOLIDIFY'); sol.thickness = 0.05; sol.offset = 0.0

# ============================================================
# LIGHTING / CAMERA / WORLD
# ============================================================
def area_light(name, loc, energy, size, target, color=(1, 1, 1)):
    ld = bpy.data.lights.new(name, 'AREA'); ld.energy = energy; ld.color = color
    ld.shape = 'DISK'; ld.size = size
    ob = bpy.data.objects.new(name, ld)
    bpy.context.scene.collection.objects.link(ob)
    ob.location = loc
    look_at(ob, target)
    return ob

area_light('Key', (0.5, -1.0, 1.6), 800, 0.9, (0.25, 0, 0.2), (1.0, 0.96, 0.90))
area_light('Fill', (-1.1, -0.6, 0.7), 280, 0.8, (0.2, 0, 0.2), (0.85, 0.90, 1.0))
area_light('Rim', (0.7, 1.1, 1.4), 650, 0.6, (0.3, 0, 0.25), (1.0, 0.95, 0.90))
area_light('Top', (0.1, 0.3, 2.3), 450, 1.0, (0.2, 0, 0), (1.0, 1.0, 1.0))

world = bpy.data.worlds.new('Studio')
scene.world = world; world.use_nodes = True
bg = world.node_tree.nodes['Background']
bg.inputs['Color'].default_value = (0.62, 0.63, 0.67, 1)
bg.inputs['Strength'].default_value = 0.35

cd = bpy.data.cameras.new('PresentationCam')
cd.lens = 60; cd.sensor_width = 36
cam = bpy.data.objects.new('PresentationCam', cd)
bpy.context.scene.collection.objects.link(cam)
cam.location = (1.00, -1.30, 0.58)
look_at(cam, (0.21, 0.0, 0.175))
cd.dof.use_dof = True
cd.dof.aperture_fstop = 7.0
focus = bpy.data.objects.new('FocusPoint', None)
bpy.context.scene.collection.objects.link(focus)
focus.location = (0.37, 0, 0.15)
cd.dof.focus_object = focus
scene.camera = cam

bpy.ops.object.select_all(action='DESELECT')
bpy.context.view_layer.update()

# ============================================================
# SAVE
# ============================================================
try:
    bpy.ops.wm.save_as_mainfile(filepath=bpy.path.abspath('//robotic_arm_studio.blend'))
except Exception as e:
    print('Save skipped:', e)
print('ROBOT ARM SCENE BUILD COMPLETE')
```