Viewports and Coordinates
This demo features three animated models, each with a different layer mask:
1) A partially transparent cylinder, with a rotation animation using yaw, pitch, and roll; this model is not lit by any of the scene lights.
2) A cube, moving along a curving path as rotation around the world axes shifts its local translation vectors; this model is lit by by directional "sunlight".
3) A torus, spinning around its local axes as it moves relative to the world axes; this model is lit by a flickering blue light.
The terrain is lit by both light sources; each mesh casts a shadow only in the light source illuminating it.