thought
Awesome! This is ready.

Now let's build the **grass clutter scatter generator**!
Let's see: we want dynamic, beautiful overgrown grass blades scattered across the ground.
Let's define a function `generate_grass_scatter(name, num_patches=350, patch_radius=1.5)`:
- We can pick random coordinates `(X, Y)` across the terrain (e.g. from -18 to 18 on both axes).
- The height `Z` is queried using `get_terrain_height(X, Y)`.
- For each position:
  - We can create a small grass clump consisting of 3 crossed diagonal blades (planes).
  - Let's define the local coordinates of 3 crossed planes:
    - Plane 1: angled at 0 degrees.
    - Plane 2: angled at 60 degrees.
    - Plane 3: angled at 120 degrees.
    - Height of each blade is around 0.2m to 0.45m.
    - Width is around 0.05m.
    - We can tilt the blades slightly outward so the clump has a natural, beautiful volume.
  - This is extremely easy to calculate:
    We define 4 vertices for each blade plane:
    `local_verts = [Vector((-w/2, 0, 0)), Vector((w/2, 0, 0)), Vector((w/2, 0, h)), Vector((-w/2, 0, h))]` (with a slight curve or tapering at the top).
    Let's write a simple diamond shape for the blade:
    `v0 = (0, -w/2, 0)`, `v1 = (0, w/2, 0)`, `v2 = (0, 0, h)` (a simple triangular leaf), or a 4-vertex plane that tapers near the top:
    `v0 = (-w/2, 0, 0)`, `v1 = (w/2, 0, 0)`, `v2 = (w/4, 0, h)`, `v3 = (-w/4, 0, h)`.
    And then we rotate this plane by 0, 60, and 120 degrees around the Z axis.
    Then we scale the entire clump randomly (e.g. by 0.7 to 1.4), and translate it to `(X, Y, Z - 0.02)` (sunk slightly into the ground).
  - Let's combine all vertices and faces for all 350 patches into a *single mesh* object called `Village_Grass`!
    This is extremely elegant, completely lightweight, and will render with ultimate speed and stunning complexity in Cycles.
Let's code this grass generator. Let's make sure it assigns the `Foliage` material to all faces. Let's write the code and run it.

import bpy
import math
import random
from mathutils import Vector, Euler, Matrix

def generate_village_grass(name, num_clumps=400, x_range=(-20.0, 20.0), y_range=(-20.0, 20.0)):
    all_verts = []
    all_faces = []

    # Simple 4-vertex tapered shape for a grass blade
    # Blade is drawn on Y plane: width along X, height along Z
    b_w = 0.04
    b_h = 0.35

    # We will build 3 intersecting blades for a single clump
    # Bl_angles = [0, 60, 120] (in degrees)
    angles_rad = [0.0, math.pi / 3.0, 2.0 * math.pi / 3.0]

    for _ in range(num_clumps):
        # Pick a random position
        rx = random.uniform(x_range[0], x_range[1])
        ry = random.uniform(y_range[0], y_range[1])
        rz = get_terrain_height(rx, ry)

        # Don't place grass inside houses (we can check if close to house positions)
        # House 1 is at (-1.0, -1.5)
        # House 2 is at (5.5, 6.0)
        # House 3 is at (-8.0, 4.0)
        in_house = False
        for hp in [Vector((-1.0, -1.5)), Vector((5.5, 6.0)), Vector((-8.0, 4.0))]:
            if (Vector((rx, ry)) - hp).length < 2.5:
                # Give a 75% chance to skip grass inside the house boundaries, to keep paths clear (or we can let some grow inside!)
                if random.random() < 0.75:
                    in_house = True
                    break
        if in_house:
            continue

        clump_scale = random.uniform(0.6, 1.4)
        clump_rot_z = random.uniform(0.0, 2.0 * math.pi)

        # World matrix for the grass clump
        clump_mat = Matrix.Translation(Vector((rx, ry, rz - 0.02))) @ Euler((random.uniform(-0.1, 0.1), random.uniform(-0.1, 0.1), clump_rot_z)).to_matrix().to_4x4()

        for angle in angles_rad:
            v_offset = len(all_verts)

            # Local matrix for the blade rotation
            # Rotate around Z, tilt slightly outward around Y (bend)
            tilt = random.uniform(0.1, 0.25)
            blade_rot = Euler((0.0, tilt, angle)).to_matrix().to_4x4()

            # Blade scale
            bh = b_h * clump_scale * random.uniform(0.8, 1.25)
            bw = b_w * clump_scale * random.uniform(0.8, 1.2)

            # 4 vertices of a slightly tapered blade
            local_verts = [
                Vector((-bw/2.0, 0, 0)),
                Vector((bw/2.0, 0, 0)),
                Vector((bw/4.0, 0, bh)),
                Vector((-bw/4.0, 0, bh))
            ]

            # Transform and add vertices
            for lv in local_verts:
                world_v = clump_mat @ (blade_rot @ lv)
                all_verts.append(world_v)

            all_faces.append((v_offset, v_offset+1, v_offset+2, v_offset+3))

    # Compile into single Mesh object
    mesh = bpy.data.meshes.new(name)
    obj = bpy.data.objects.new(name, mesh)
    bpy.context.collection.objects.link(obj)

    v_tuples = [v.to_tuple() for v in all_verts]
    mesh.from_pydata(v_tuples, [], all_faces)
    mesh.update()

    mat_foliage = bpy.data.materials.get("Foliage")
    if mat_foliage:
        obj.data.materials.append(mat_foliage)

    bpy.ops.object.select_all(action='DESELECT')
    obj.select_set(True)
    bpy.context.view_layer.objects.active = obj
    bpy.ops.object.shade_smooth()

    return obj

generate_village_grass("Village_Grass", num_clumps=2000)
print("Grass scatter completed!")

Generate and compile optimized village-wide grass cover mesh with obstacle avoidance near houses


Error executing code: Communication error with Blender: Code execution error: name 'get_terrain_height' is not defined