The computer gives the ability to create images that look absolutely real. Especially with the latest techniques in rendering, texture mapping, ray tracing and radiosity, you can make an object look just like it’s made of marble or rubber or whatever you wish. But to make it look like marble or rubber when it is in motion, has very little to do with the way the object is rendered. It has everything to do with the way the object is animated. It is animation that gives an object its physical properties. More that anything else, the timing of the movement of an object defines the weight of that object.