An important notion to keep in mind is that a CG image need not be created entirely in a single render. Most of the time, it’s better to composite different elements together to form the final image. Professional CG workflow almost always requires multiple render passes that are composited together later for the maximum in efficiency and quality.
Maya does a great job of making rendering in layers much easier with render layers. As you saw earlier in this book, using Display layers helps a lot in keeping your scene organized. Render layers operate in basically the same way, although they function by separating different elements of the scene into separate renders.
The functionality behind render layers is very powerful. We’ll address ...