Re:Impressive. (Score 1)

I think you're referring to normal mapping, which is what of the latest games are using. Actually, the Unreal 3 tech is pretty cool. They start with a 1-2 MILLION poly mesh, simplify it to 20-50 THOUSAND, and then to raycasting/tracing (I'm not sure what's it called), from the low-poly model to the high poly model to get the normal map, and use that for rendering. They get the about the same amount of geometric detail as the other games of the day, but 100x more lighting detail.

Unreal 3 tech can be found Here.