LocalFilamentEngine

The Engine backing the enclosing rememberFilamentScene, or null outside one.

Read it to give your own scene composables the same engine default the built-in loaders use:

@Composable
fun rememberMyResource(
    engine: Engine = LocalFilamentEngine.current ?: error("no engine in scope"),
): MyResource = ...

For the Scene itself — adding raw entities, per-frame work — use FilamentEffect, which hands you both the engine and the scene and manages the effect's lifetime.