as the topic says , i would like to know how to make a 3d world like quake or doom. I know it not easy. But i need to find tutorials about it. Can anyone tell me what i need to do to create a 3d world. I know it involves something called MATRIX right ? Thanks "The shortcut is not always the best way " Metal Typhoon

Here are some links to some introductory allegro 3d tutorials:
http://www.rbsite.freeserve.co.uk/mystex22.htm
Explains example 22, working up with points, wireframe, and I think flat shading, then textures.
http://home.planet.nl/~monstrous/logbook.html
Explains the easier things and a little more like clipping (the guy explains why clip3d is better than his own), file i/o (this is all in c), and bsp trees. Actually, it''s not all explained but the source is good enough to learn by.

Since you say like Quake or Doom, I suggust you look into ''Portals''. They would probally fit in something like that. I don''t know how thoes games are built but the source code is out.