Stereo: Three sorry cases studies

You probably have seen movies such as Avatar or other cg movies from Disney, Pixar, Dreamworks etc ... which are made in stereoscopic 3d.  The principle is to render two images from two different cameras placed at standard inter-ocular distance from each other. By projecting the two images and using special 3d glasses to filter out each side, you then get a sense of depth as in a real world.
In cg movies, working in stereo poses a lot of challenges so that it works well, doesn't look too gimmicky and doesn't give any headaches to the viewer.

Cyclops don't bother