i''m making a space invaders clone and i''m having a really hard time making collision detection Can someone tell me where to find info on this subject? Right now i''m checking if any point inside an object is inside another object. it works fine cause its 2D and there are few ships and bullets but i wonder how they do it in quake3, where there are lots of objects in 3D coordinates, i don''t think they just check every objects position with all the other objects Sorry if i didn''t explain myself right, but english is not my natural language

This website is loaded with threads and articles on the subject of collision detection; I posted extensively on the topic in this same forum just about three weeks ago. I suggest you familiarize yourself with the search tool (look up, then right) as well as the "Articles and Resources" section. You''ll find a lot there.

As to how the number of collision tests are reduced in commercial applications like Quake, keep in mind that a collision between object A and object B is the same as a collision between B and A. Therefore, it is possible to organize your objects in a data structure that makes sure you only perform one test per pair of objects. I forget the names of some common schemes, but searching the Maths and Physics forum will give you tons of results.