sync

Content/Python/generate_procedural_terrain.py

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+"""Run inside Unreal (Python console / Execute Python Script).
+
+Reads terrain_config.json (next to this script) and:
+  1. builds a heightfield mesh with GeometryScript (fractal value noise),
+     bakes it to a StaticMesh, and drops it into the level;
+  2. scatters tree/rock StaticMeshActors across it per "scatter_layers",
+     using the same noise field so foliage height always matches the
+     ground beneath it (no raycasting needed).
+
+Run import_environment_assets.py first so the mesh paths referenced in
+terrain_config.json actually exist.
+"""
+import os, json, math, random, unreal
+
+CONFIG_PATH = os.path.join(os.path.dirname(os.path.abspath(__file__)), "terrain_config.json")
+
+asset_tools = unreal.AssetToolsHelpers.get_asset_tools()
+actor_subsystem = unreal.get_editor_subsystem(unreal.EditorActorSubsystem)
+
+
+# ---------------------------------------------------------------------------
+# Fractal value noise (pure Python, no engine dependency) -------------------
+# ---------------------------------------------------------------------------
+class ValueNoise2D:
+    """Seeded, smooth, tileable-enough value noise for terrain-style height fields."""
+
+    def __init__(self, seed):
+        rng = random.Random(seed)
+        table = list(range(256))
+        rng.shuffle(table)
+        self._perm = table + table  # avoid overflow when indexing i+1
+
+    @staticmethod
+    def _fade(t):
+        return t * t * t * (t * (t * 6 - 15) + 10)
+
+    @staticmethod
+    def _lerp(a, b, t):
+        return a + t * (b - a)
+
+    def _gradient(self, ix, iy):
+        h = self._perm[(self._perm[ix & 255] + iy) & 255]
+        angle = (h / 255.0) * 2.0 * math.pi
+        return math.cos(angle), math.sin(angle)
+
+    def sample(self, x, y):
+        x0, y0 = math.floor(x), math.floor(y)
+        x1, y1 = x0 + 1, y0 + 1
+        sx, sy = x - x0, y - y0
+
+        def dot_grid(ix, iy, px, py):
+            gx, gy = self._gradient(ix, iy)
+            return gx * (px - ix) + gy * (py - iy)
+
+        n00 = dot_grid(x0, y0, x, y)
+        n10 = dot_grid(x1, y0, x, y)
+        n01 = dot_grid(x0, y1, x, y)
+        n11 = dot_grid(x1, y1, x, y)
+
+        u, v = self._fade(sx), self._fade(sy)
+        return self._lerp(self._lerp(n00, n10, u), self._lerp(n01, n11, u), v)
+
+
+class FractalHeightField:
+    def __init__(self, noise_cfg, height_scale):
+        self.height_scale = height_scale
+        self.frequency = noise_cfg["frequency"]
+        self.octaves = noise_cfg["octaves"]
+        self.lacunarity = noise_cfg["lacunarity"]
+        self.gain = noise_cfg["gain"]
+        self.noise = ValueNoise2D(noise_cfg["seed"])
+
+    def height(self, x, y):
+        amplitude, frequency, total, max_amp = 1.0, self.frequency, 0.0, 0.0
+        for _ in range(self.octaves):
+            total += amplitude * self.noise.sample(x * frequency, y * frequency)
+            max_amp += amplitude
+            amplitude *= self.gain
+            frequency *= self.lacunarity
+        return (total / max_amp) * self.height_scale
+
+    def normal(self, x, y, step=25.0):
+        h_l = self.height(x - step, y)
+        h_r = self.height(x + step, y)
+        h_d = self.height(x, y - step)
+        h_u = self.height(x, y + step)
+        # tangents along X and Y, cross product gives the surface normal.
+        tangent_x = unreal.Vector(2 * step, 0.0, h_r - h_l)
+        tangent_y = unreal.Vector(0.0, 2 * step, h_u - h_d)
+        nx = tangent_x.y * tangent_y.z - tangent_x.z * tangent_y.y
+        ny = tangent_x.z * tangent_y.x - tangent_x.x * tangent_y.z
+        nz = tangent_x.x * tangent_y.y - tangent_x.y * tangent_y.x
+        length = math.sqrt(nx * nx + ny * ny + nz * nz) or 1.0
+        return unreal.Vector(nx / length, ny / length, nz / length)
+
+
+# ---------------------------------------------------------------------------
+# Terrain mesh ----------------------------------------------------------------
+# ---------------------------------------------------------------------------
+def build_terrain_mesh(cfg, field):
+    steps = max(2, cfg["resolution"])
+    mesh = unreal.DynamicMesh()
+    primitive_options = unreal.GeometryScriptPrimitiveOptions()
+    mesh = unreal.GeometryScript_Primitives.append_rectangle_xy(
+        mesh, primitive_options, unreal.Transform(),
+        dimension_x=cfg["size_x"], dimension_y=cfg["size_y"],
+        steps_width=steps, steps_height=steps,
+    )
+
+    mesh, position_list, _has_gaps = unreal.GeometryScript_MeshQueries.get_all_vertex_positions(mesh, False)
+    positions = unreal.GeometryScript_List.convert_vector_list_to_array(position_list)
+
+    min_x = min_y = float("inf")
+    max_x = max_y = float("-inf")
+    displaced = []
+    for p in positions:
+        z = field.height(p.x, p.y)
+        displaced.append(unreal.Vector(p.x, p.y, z))
+        min_x, max_x = min(min_x, p.x), max(max_x, p.x)
+        min_y, max_y = min(min_y, p.y), max(max_y, p.y)
+
+    new_list = unreal.GeometryScript_List.convert_array_to_vector_list(displaced)
+    mesh = unreal.GeometryScript_MeshEdits.set_all_mesh_vertex_positions(mesh, new_list)
+    mesh = unreal.GeometryScript_Normals.set_per_vertex_normals(mesh)
+
+    dest_path = cfg["dest_path"]
+    asset_name = cfg["asset_name"]
+    if unreal.EditorAssetLibrary.does_asset_exist(f"{dest_path}/{asset_name}"):
+        unreal.EditorAssetLibrary.delete_asset(f"{dest_path}/{asset_name}")
+    static_mesh = asset_tools.create_asset(asset_name, dest_path, unreal.StaticMesh, unreal.StaticMeshFactoryNew())
+
+    copy_options = unreal.GeometryScriptCopyMeshToAssetOptions()
+    target_lod = unreal.GeometryScriptMeshWriteLOD()
+    unreal.GeometryScript_AssetUtils.copy_mesh_to_static_mesh(mesh, static_mesh, copy_options, target_lod)
+    unreal.EditorAssetLibrary.save_asset(static_mesh.get_path_name())
+
+    bounds = (min_x, max_x, min_y, max_y)
+    return static_mesh, bounds
+
+
+# ---------------------------------------------------------------------------
+# Foliage scatter --------------------------------------------------------------
+# ---------------------------------------------------------------------------
+def scatter_layer(layer_cfg, field, bounds, origin, base_folder):
+    min_x, max_x, min_y, max_y = bounds
+    rng = random.Random(layer_cfg.get("seed", 0))
+    meshes = [unreal.load_asset(path) for path in layer_cfg["meshes"]]
+    meshes = [m for m in meshes if m is not None]
+    if not meshes:
+        print(f"  [{layer_cfg['name']}] no valid meshes found, skipping")
+        return 0
+
+    max_slope_cos = math.cos(math.radians(layer_cfg.get("max_slope_degrees", 90.0)))
+    min_spacing = layer_cfg.get("min_spacing", 0.0)
+    min_spacing_sqr = min_spacing * min_spacing
+
+    placed_points = []
+    spawned = 0
+    max_attempts = layer_cfg["count"] * 25
+
+    attempts = 0
+    while spawned < layer_cfg["count"] and attempts < max_attempts:
+        attempts += 1
+        x = rng.uniform(min_x, max_x)
+        y = rng.uniform(min_y, max_y)
+
+        if min_spacing_sqr > 0.0 and any((x - px) ** 2 + (y - py) ** 2 < min_spacing_sqr for px, py in placed_points):
+            continue
+
+        z = field.height(x, y)
+        if not (layer_cfg["min_height"] <= z <= layer_cfg["max_height"]):
+            continue
+
+        normal = field.normal(x, y)
+        if normal.z < max_slope_cos:
+            continue
+
+        placed_points.append((x, y))
+
+        mesh = rng.choice(meshes)
+        location = unreal.Vector(origin.x + x, origin.y + y, origin.z + z)
+        yaw = rng.uniform(0.0, 360.0)
+        if layer_cfg.get("align_to_normal", False):
+            # Approximate tilt from the surface normal; good enough for gentle slopes.
+            pitch = -math.degrees(math.atan2(normal.x, normal.z))
+            roll = math.degrees(math.atan2(normal.y, normal.z))
+            rotation = unreal.Rotator(roll=roll, pitch=pitch, yaw=yaw)
+        else:
+            rotation = unreal.Rotator(roll=0.0, pitch=0.0, yaw=yaw)
+
+        actor = actor_subsystem.spawn_actor_from_object(mesh, location, rotation)
+        scale = rng.uniform(layer_cfg["min_scale"], layer_cfg["max_scale"])
+        actor.set_actor_scale3d(unreal.Vector(scale, scale, scale))
+        actor.set_folder_path(f"{base_folder}/{layer_cfg['name']}")
+        actor.set_actor_label(f"{layer_cfg['name']}_{spawned:04d}")
+        spawned += 1
+
+    print(f"  [{layer_cfg['name']}] placed {spawned}/{layer_cfg['count']} ({attempts} attempts)")
+    return spawned
+
+
+# ---------------------------------------------------------------------------
+def main():
+    with open(CONFIG_PATH, "r") as f:
+        config = json.load(f)
+
+    terrain_cfg = config["terrain"]
+    field = FractalHeightField(terrain_cfg["noise"], terrain_cfg["height_scale"])
+
+    print("Building terrain mesh...")
+    static_mesh, bounds = build_terrain_mesh(terrain_cfg, field)
+
+    loc = terrain_cfg["location"]
+    origin = unreal.Vector(loc[0], loc[1], loc[2])
+    terrain_actor = actor_subsystem.spawn_actor_from_object(static_mesh, origin, unreal.Rotator(0, 0, 0))
+    terrain_actor.set_folder_path("ProceduralTerrain")
+    terrain_actor.set_actor_label("ProceduralTerrain")
+
+    print("Scattering foliage layers...")
+    for layer_cfg in config.get("scatter_layers", []):
+        scatter_layer(layer_cfg, field, bounds, origin, "ProceduralTerrain")
+
+    print("Done.")
+
+
+main()

Content/Python/import_environment_assets.py

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+"""Run inside Unreal (Python console / Execute Python Script).
+
+Imports the tree (FBX) and rock (OBJ) meshes from DemoAssets as StaticMesh
+assets, so generate_procedural_terrain.py has something to scatter.
+"""
+import os, unreal
+
+DEMO_ROOT = r"C:\Users\koleg\Documents\Unreal Projects\ExampleProject\DemoAssets"
+DEST_ROOT = "/Game/ImportedAssets"
+
+# folder under DEMO_ROOT -> (destination subfolder, file extension)
+SOURCES = {
+    "trees": ("Trees", ".fbx"),
+    "rocks": ("Rocks", ".obj"),
+}
+
+asset_tools = unreal.AssetToolsHelpers.get_asset_tools()
+
+
+def import_task(filename, name, dest_path, options=None):
+    task = unreal.AssetImportTask()
+    task.filename = filename
+    task.destination_path = dest_path
+    task.destination_name = name
+    task.automated = True
+    task.save = True
+    task.replace_existing = True
+    if options:
+        task.options = options
+    asset_tools.import_asset_tasks([task])
+    return unreal.load_asset(f"{dest_path}/{name}")
+
+
+def import_static_mesh(filename, name, dest_path):
+    ext = os.path.splitext(filename)[1].lower()
+    options = None
+    if ext == ".fbx":
+        options = unreal.FbxImportUI()
+        options.mesh_type_to_import = unreal.FBXImportType.FBXIT_STATIC_MESH
+        options.import_mesh = True
+        options.import_as_skeletal = False
+        options.import_materials = True
+        options.import_textures = True
+        options.static_mesh_import_data.combine_meshes = True
+    # OBJ has no import-options struct exposed to Python; Interchange picks sane defaults.
+    return import_task(filename, name, dest_path, options)
+
+
+imported = []
+for src_folder, (dest_subfolder, ext) in SOURCES.items():
+    src_dir = os.path.join(DEMO_ROOT, src_folder)
+    if not os.path.isdir(src_dir):
+        continue
+    dest_path = f"{DEST_ROOT}/{dest_subfolder}"
+
+    for f in sorted(os.listdir(src_dir)):
+        stem, file_ext = os.path.splitext(f)
+        if file_ext.lower() != ext:
+            continue
+        name = f"SM_{stem}"
+        mesh = import_static_mesh(os.path.join(src_dir, f), name, dest_path)
+        imported.append(f"{dest_path}/{name}")
+
+print(f"Imported {len(imported)} static mesh(es):")
+for path in imported:
+    print(f"  {path}")

Content/Python/terrain_config.json

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+{
+  "terrain": {
+    "location": [0.0, 0.0, 0.0],
+    "size_x": 8000.0,
+    "size_y": 8000.0,
+    "resolution": 96,
+    "height_scale": 600.0,
+    "dest_path": "/Game/ImportedAssets/Terrain",
+    "asset_name": "SM_ProceduralTerrain",
+    "noise": {
+      "seed": 1337,
+      "octaves": 5,
+      "frequency": 0.00035,
+      "lacunarity": 2.0,
+      "gain": 0.5
+    }
+  },
+  "scatter_layers": [
+    {
+      "name": "Trees",
+      "meshes": [
+        "/Game/ImportedAssets/Trees/SM_tree01",
+        "/Game/ImportedAssets/Trees/SM_tree02",
+        "/Game/ImportedAssets/Trees/SM_tree03",
+        "/Game/ImportedAssets/Trees/SM_tree04"
+      ],
+      "count": 250,
+      "min_height": -50.0,
+      "max_height": 350.0,
+      "max_slope_degrees": 25.0,
+      "min_scale": 0.85,
+      "max_scale": 1.3,
+      "align_to_normal": true,
+      "min_spacing": 250.0,
+      "seed": 7
+    },
+    {
+      "name": "Rocks",
+      "meshes": [
+        "/Game/ImportedAssets/Rocks/SM_rock1",
+        "/Game/ImportedAssets/Rocks/SM_rock2",
+        "/Game/ImportedAssets/Rocks/SM_rock3"
+      ],
+      "count": 150,
+      "min_height": -100.0,
+      "max_height": 600.0,
+      "max_slope_degrees": 45.0,
+      "min_scale": 0.5,
+      "max_scale": 2.0,
+      "align_to_normal": true,
+      "min_spacing": 150.0,
+      "seed": 42
+    }
+  ]
+}