That's exactly what the render element output feature does, yes. It outputs separate images for each "pass" (element) you select to to save, including the typical depth, alpha, etc. as well as motion vectors, separate lighting passes for atmosphere and surfaces, etc. The Layers functionality allows you to group the scene and output only components from a given group (layer) from a particular renderer, which gives you even more control than just full-scene elements. These two things can be combined, of course.
- Oshyan