How does 3d rendering work?

Answer 1

3d Animation works like clay modeling but in a computer. You start with basic shapes and then you tweak it to create a 3d figure.you can view your model from any possible angle. Then you can add a sort of skeleton to make it move. then you can tell each bone or the whole thing how and when to move. Then hit the play button. This is the simple answer. there is a great deal of complexity to creating full 3d animations.

Answer 2

Your computer will assign each of its cores to calculate a portion of an image through an external program, most likely mental ray or render man, your computer can work on more portions at a time if it has more cores however it will do each piece slower if you are using Hyper Threading to boost your number of cores.

Each core will calculate the objects in the foreground and background in the 3d space and flatten them out onto a two dimensional image that represents a three dimensional scene.