sync

Content/Python/generate_procedural_terrain.py

@@ -9,10 +9,16 @@ Reads terrain_config.json (next to this script) and:
 
 Run import_environment_assets.py first so the mesh paths referenced in
 terrain_config.json actually exist.
+
+Set the TERRAIN_CONFIG env var to point at a different config file, e.g. to
+run terrain_config_variants_demo.json without touching the default config.
 """
 import os, json, math, random, unreal
 
-CONFIG_PATH = os.path.join(os.path.dirname(os.path.abspath(__file__)), "terrain_config.json")
+CONFIG_PATH = os.environ.get(
+    "TERRAIN_CONFIG",
+    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)
@@ -125,19 +131,33 @@ def build_terrain_mesh(cfg, field):
 
     dest_path = cfg["dest_path"]
     asset_name = cfg["asset_name"]
-    if unreal.EditorAssetLibrary.does_asset_exist(f"{dest_path}/{asset_name}"):
+    asset_path = f"{dest_path}/{asset_name}"
-        unreal.EditorAssetLibrary.delete_asset(f"{dest_path}/{asset_name}")
+    if unreal.EditorAssetLibrary.does_asset_exist(asset_path):
-    static_mesh = asset_tools.create_asset(asset_name, dest_path, unreal.StaticMesh, unreal.StaticMeshFactoryNew())
+        unreal.EditorAssetLibrary.delete_asset(asset_path)
 
-    copy_options = unreal.GeometryScriptCopyMeshToAssetOptions()
+    create_options = unreal.GeometryScriptCreateNewStaticMeshAssetOptions()
-    target_lod = unreal.GeometryScriptMeshWriteLOD()
+    static_mesh, _outcome = unreal.GeometryScript_NewAssetUtils.create_new_static_mesh_asset_from_mesh(
-    unreal.GeometryScript_AssetUtils.copy_mesh_to_static_mesh(mesh, static_mesh, copy_options, target_lod)
+        mesh, asset_path, create_options,
+    )
     unreal.EditorAssetLibrary.save_asset(static_mesh.get_path_name())
 
     bounds = (min_x, max_x, min_y, max_y)
     return static_mesh, bounds
 
 
+_mesh_base_z_cache = {}
+
+
+def mesh_base_z(mesh):
+    """Local-space Z of the mesh's lowest point, so we can plant its base on the
+    ground instead of its (often bounding-box-centered) pivot."""
+    path = mesh.get_path_name()
+    if path not in _mesh_base_z_cache:
+        box = mesh.get_bounding_box()
+        _mesh_base_z_cache[path] = box.min.z
+    return _mesh_base_z_cache[path]
+
+
 # ---------------------------------------------------------------------------
 # Foliage scatter --------------------------------------------------------------
 # ---------------------------------------------------------------------------
@@ -178,7 +198,11 @@ def scatter_layer(layer_cfg, field, bounds, origin, base_folder):
         placed_points.append((x, y))
 
         mesh = rng.choice(meshes)
-        location = unreal.Vector(origin.x + x, origin.y + y, origin.z + z)
+        scale = rng.uniform(layer_cfg["min_scale"], layer_cfg["max_scale"])
+        # Shift up by -min_z*scale so the mesh's lowest vertex sits on the ground,
+        # regardless of where the source asset's pivot was authored.
+        ground_offset = -mesh_base_z(mesh) * scale
+        location = unreal.Vector(origin.x + x, origin.y + y, origin.z + z + ground_offset)
         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.
@@ -189,7 +213,6 @@ def scatter_layer(layer_cfg, field, bounds, origin, base_folder):
             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}")
@@ -199,28 +222,112 @@ def scatter_layer(layer_cfg, field, bounds, origin, base_folder):
     return spawned
 
 
-# ---------------------------------------------------------------------------
+def place_explicit(entries, field, origin, base_folder):
-def main():
+    """Places an exact, hand-authored (or externally-generated) list of instances.
-    with open(CONFIG_PATH, "r") as f:
-        config = json.load(f)
 
-    terrain_cfg = config["terrain"]
+    Unlike scatter_layer's density/slope rules, this reproduces a literal
+    manifest byte-for-byte: the same JSON always yields the same named
+    landmarks at the same coordinates - useful for hero props, quest markers,
+    or a layout exported from an external design tool, none of which a
+    rule-driven scatter (ours or a graph-based tool like PCG) is meant to pin down.
+    """
+    placed = 0
+    for entry in entries:
+        mesh = unreal.load_asset(entry["mesh"])
+        if mesh is None:
+            print(f"  [explicit] missing mesh asset: {entry['mesh']}")
+            continue
+
+        x, y, z_offset = entry.get("location", [0.0, 0.0, 0.0])
+        scale = entry.get("scale", 1.0)
+        if isinstance(scale, list):
+            scale_vec = unreal.Vector(*scale)
+        else:
+            scale_vec = unreal.Vector(scale, scale, scale)
+
+        z = z_offset
+        if entry.get("snap_to_terrain", True):
+            z += field.height(x, y) - mesh_base_z(mesh) * scale_vec.z
+
+        roll, pitch, yaw = entry.get("rotation", [0.0, 0.0, 0.0])
+        location = unreal.Vector(origin.x + x, origin.y + y, origin.z + z)
+        rotation = unreal.Rotator(roll=roll, pitch=pitch, yaw=yaw)
+
+        actor = actor_subsystem.spawn_actor_from_object(mesh, location, rotation)
+        actor.set_actor_scale3d(scale_vec)
+        actor.set_folder_path(f"{base_folder}/Explicit")
+        actor.set_actor_label(entry.get("name", f"Explicit_{placed:04d}"))
+        placed += 1
+
+    print(f"  [explicit] placed {placed}/{len(entries)}")
+    return placed
+
+
+def generate_tile(config, terrain_cfg, tile_label):
+    """Builds one terrain + its scatter layers + its explicit placements, all
+    under a dedicated Outliner folder so multiple tiles can coexist in one level.
+    """
     field = FractalHeightField(terrain_cfg["noise"], terrain_cfg["height_scale"])
+    base_folder = f"ProceduralTerrain/{tile_label}"
 
-    print("Building terrain mesh...")
+    print(f"[{tile_label}] building terrain mesh (seed={terrain_cfg['noise']['seed']})...")
     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_folder_path(base_folder)
-    terrain_actor.set_actor_label("ProceduralTerrain")
+    terrain_actor.set_actor_label(f"Terrain_{tile_label}")
 
-    print("Scattering foliage layers...")
     for layer_cfg in config.get("scatter_layers", []):
-        scatter_layer(layer_cfg, field, bounds, origin, "ProceduralTerrain")
+        scatter_layer(layer_cfg, field, bounds, origin, base_folder)
 
+    explicit_entries = config.get("explicit_placements", [])
+    if explicit_entries:
+        place_explicit(explicit_entries, field, origin, base_folder)
+
+
+def main():
+    with open(CONFIG_PATH, "r") as f:
+        config = json.load(f)
+
+    base_terrain_cfg = config["terrain"]
+    variants = config.get("variants")
+
+    if not variants:
+        # Single-tile mode: unchanged behavior for existing configs.
+        generate_tile(config, base_terrain_cfg, "Main")
         print("Done.")
+        return
+
+    # Variant mode: one JSON list of seeds becomes N independent, deterministic
+    # tiles laid out side by side in a single run - each a full reproducible
+    # world driven by nothing but that seed. There's no "batch-produce N baked,
+    # comparable layouts from one data file" workflow in the Foliage tool or a
+    # PCG graph; you'd re-author or re-seed each one by hand, one at a time.
+    gap = base_terrain_cfg["size_x"] * 1.2
+    base_seed = base_terrain_cfg["noise"]["seed"]
+    base_layer_seeds = {layer["name"]: layer.get("seed", 0) for layer in config.get("scatter_layers", [])}
+
+    for i, seed_offset in enumerate(variants):
+        tile_label = f"Variant_{seed_offset}"
+        terrain_cfg = json.loads(json.dumps(base_terrain_cfg))  # cheap deep copy
+        terrain_cfg["noise"]["seed"] = base_seed + seed_offset
+        terrain_cfg["asset_name"] = f"{base_terrain_cfg['asset_name']}_{tile_label}"
+        terrain_cfg["location"] = [
+            base_terrain_cfg["location"][0] + i * gap,
+            base_terrain_cfg["location"][1],
+            base_terrain_cfg["location"][2],
+        ]
+
+        tile_config = json.loads(json.dumps(config))
+        tile_config["terrain"] = terrain_cfg
+        for layer_cfg in tile_config.get("scatter_layers", []):
+            layer_cfg["seed"] = base_layer_seeds.get(layer_cfg["name"], 0) + seed_offset
+
+        generate_tile(tile_config, terrain_cfg, tile_label)
+
+    print(f"Done: {len(variants)} variant(s) generated side by side.")
 
 
 main()

Content/Python/terrain_config.json

@@ -51,5 +51,23 @@
       "min_spacing": 150.0,
       "seed": 42
     }
+  ],
+  "explicit_placements": [
+    {
+      "name": "LandmarkTree_Overlook",
+      "mesh": "/Game/ImportedAssets/Trees/SM_tree01",
+      "location": [1200.0, 800.0, 0.0],
+      "snap_to_terrain": true,
+      "rotation": [0.0, 0.0, 30.0],
+      "scale": 2.5
+    },
+    {
+      "name": "RockCairn_Waypoint",
+      "mesh": "/Game/ImportedAssets/Rocks/SM_rock2",
+      "location": [-1500.0, -600.0, 0.0],
+      "snap_to_terrain": true,
+      "rotation": [0.0, 0.0, 0.0],
+      "scale": [1.0, 1.0, 1.8]
+    }
   ]
 }

Content/Python/terrain_config_variants_demo.json

@@ -0,0 +1,57 @@
+{
+  "_comment": "Presentation demo: run with TERRAIN_CONFIG env var pointed at this file. One 'variants' list turns this single config into 4 independent, deterministic worlds laid out side by side in one run - no hand re-authoring or re-painting per tile.",
+  "terrain": {
+    "location": [0.0, 0.0, 0.0],
+    "size_x": 3000.0,
+    "size_y": 3000.0,
+    "resolution": 48,
+    "height_scale": 500.0,
+    "dest_path": "/Game/ImportedAssets/Terrain",
+    "asset_name": "SM_TerrainDemo",
+    "noise": {
+      "seed": 1000,
+      "octaves": 5,
+      "frequency": 0.0006,
+      "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": 60,
+      "min_height": -50.0,
+      "max_height": 300.0,
+      "max_slope_degrees": 25.0,
+      "min_scale": 0.85,
+      "max_scale": 1.3,
+      "align_to_normal": true,
+      "min_spacing": 200.0,
+      "seed": 7
+    },
+    {
+      "name": "Rocks",
+      "meshes": [
+        "/Game/ImportedAssets/Rocks/SM_rock1",
+        "/Game/ImportedAssets/Rocks/SM_rock2",
+        "/Game/ImportedAssets/Rocks/SM_rock3"
+      ],
+      "count": 30,
+      "min_height": -100.0,
+      "max_height": 500.0,
+      "max_slope_degrees": 45.0,
+      "min_scale": 0.5,
+      "max_scale": 2.0,
+      "align_to_normal": true,
+      "min_spacing": 150.0,
+      "seed": 42
+    }
+  ],
+  "variants": [0, 1, 2, 3]
+}