As usual, the compositing role was the last step in the process. The image had already been broken down into every object that needed to be separate. Each object had been roto’d and geometry tracked. The geometry and roto was taken into an in house piece of software where the stereo depth was setup by a stereographer. This software produced a disparity map for every object in the scene.
Every time we started a shot there was an automated script that took all the roto and the disparity maps and rebuilt the stereo shot in Nuke. It was then our job as compositors to do all the paint work needed to clean up areas of occlusion, and to treat some of the edges to reduce artifacts that might appear in stereo.