My dream is to have a 3d world simialer to Motocross Madness 2, about 1/4 the level size, BUT with some SOLID buildings on par with Quake 2 or Half Life, with about 14-20 players in game. The world itself would be static. Only the player models and (maybe) a vehicle or two would be dynamic. Playablility not Eyecandyitius. In all of your opinions, what is the best route to go for the engine? Voxel (uhm, relax, I''m just joking) BSP PVS PORTALS QUADTREE OCTREE KD_TREE HIEGHT MAPS LOD/ROAM ???? any/all/none of the above? Please elaborate on your choice/choice''s and a brief how-to-implement (no code just theory) to help me understand why you suggest what you do. Also if you could, name any articles or books that contain information to collaborate your choice, it would be appreciated. Thank you up front for the time and effort to answer this post, .Aman. aman@twcny.rr.com