ABSTRACT
When compositing CGI some very different issues arise as opposed to greenscreen shots. A very fundamental yet confusing issue is the whole premultiply/unpremultiply thing, so that will be addressed fi rst. Also, CGI elements are now rendered in multiple separate light passes – ambient, specular, refl ection, occlusion, and so on. The modern compositor is expected to know how to deal with these multi-pass CGI renders. Additionally, there is an increasing need to know how to work with High Dynamic Range (HDR) images when compositing CGI.
