I read a fascinating article by Mick West in Game Developer magazine (August 2006). It’s called "A Shattered Reality," and it’s about realism in games. One of the things we often strive for in games is realism. There are scads of SIGGRAPH articles that include "realistic" in the title: realistic hair, realistic skin, realistic clouds, realistic materials, realistic facial animation, realistic trees, and on and on. Mick makes a bold statement:
Hyper-realistic simulation is not yet feasible in video games — not even close.
He then goes on to back up his claim in great level of detail. The specific example he uses is shattering glass. Scientists don’t even understand what makes glass break, let alone how to physically simulate it. The point of the article is that you can often get perfectly realistic results in games by avoiding massive amounts of physics calculations, and simply simulating observable effects. The example he provides for shattered glass is brilliant. Highly recommended reading.