One very important thing I'm learning by being at Ghost is how to use Mental Ray. It used to be a stand-alone render that has been recently incorporated into Maya. The rendering stage is a 3d program's final stage of converting everything in a scene into it's final pixel images. On the left side of the sceen is a skull textured and rendered with Maya's default renderer, and on the right is a skull rendered in Mental Ray. Mental Ray has amazing capabilities to simulate real light and materials. The skull has a technique called sub-surface scattering on it, which allows light to hit geometry and bounce around underneath the surface of an object before it is finally reflected back.
Unfortunetly, I'm probably not going to be able to use mental ray very much on the heart surgery animation I'm working on. While mental ray is a lot mroe powerful, the time it takes to render each frame can take considerably longer. Depending on how advanced a scene in, a single frame that may take a minute in the normal renderer might take over an hour with Mental Ray features on. Mental Ray also takes much longer to setup in a scene because it is far more complex and is much more likely to cause errors than the default renderer. Basically, since Mental Ray usually takes much longer to produce work, it costs more to use. This means most companies that are not concered withcinematic quality simply stay away from Mental Ray because they can't budget for it. On the up side, One of the programers at Ghost gave me a training DVD to study Mental Ray in much more depth. There are a lot of techniques which signiticantly reduce setup and render time, but it requires a lot of training and knowledge to use them all. This is essentially why some CGI artists specialize in rendering exclusively.