#determinism

When the world is deterministically generated from a spec, a save is {version, spec, edits[]}, never a geometry snapshot. Load = validate → regenerate → replay edits. Same format works for save, co-op edit sync, and late-join replay.

Two proven architectures on top of the engine networking primitives: replicate the generator spec (not the geometry) for deterministic worlds, and retrofit local-only gameplay systems to host-authority without breaking single-player.

A joining client can build a code-generated world twice -- once on local StartupScene load, once on the networked scene handoff. A non-idempotent world author that clears its tracking lists but never destroys prior GameObjects stacks a whole second world. Make the author idempotent, and compute any sync hash from the build recipe, not a live scene scan.

bpy.ops.wm.obj_export can reorder face lines across runs on the same mesh: diff the manifest, not the raw OBJ bytes.

Dev-host streaming sends assemblies and compiled assets but NOT loose data files read via FileSystem.Mounted: a joining client that loads a raw JSON manifest builds differently, silently.

Deferred Destroy() leaves the old code-built world overlapping the fresh one for a frame: use DestroyImmediate for teardown before rebuild, and pair it with a recipe hash for belt-and-suspenders join verification.

Sandbox.Decal self-seeds with Random.Shared.Int(10000) on enable: a decal spawned identically on two peers renders differently by default.