Built-in prefabs

Prefabs live in the Rust crate crates/scene (PrefabLibrary::builtin). Each has a stable numeric ID stored in level JSON as prefab_id. Do not renumber IDs without bumping format_version and migrating levels.

Rendering note (MVP)

The engine currently draws instances from positions; distinct meshes per prefab type are not implemented yet. All prefabs still appear in the ECS as Position + PrefabRef so gameplay and future rendering can branch on prefab_id.

Catalog

ID	Editor name	Category	Intended use
1	Cube	Primitive	Placeholder solid / blocking volume.
2	Sphere (proxy)	Primitive	Stand-in for round props until mesh variants exist.
3	Spawn point	Gameplay	Player / pawn spawn marker.
4	Waypoint	Gameplay	Path, AI, or script anchor.
5	Light probe	Utility	Future lighting sample location.
6	Tree	Environment	Vegetation placeholder.
7	Rock	Environment	Scatter / obstacle placeholder.
8	Terrain marker	Environment	Annotates terrain regions; full terrain painting is separate from this marker.
9	Camera	Utility	Spawns an ECS CameraRig at the object position; the first active camera supplies the engine view matrix. Serialized via optional camera on PlacedObject (fov/yaw/pitch degrees, active).

Constants in code

Rust code can use scene::ids::CUBE, scene::ids::SPAWN_POINT, etc., from the scene crate (see crates/scene/src/prefabs.rs).

Adding prefabs

1. Add a new PrefabInfo entry in PrefabLibrary with a new unused ID.

2. Document it here and in the repository README.md prefab table.

3. When per-prefab rendering exists, hook PrefabRef in the renderer.