   Terrain Collision...
  Hey all,I understand for model to model collision tests, you''d use a bounding box / sphere and perhaps a couple of ray traces.How are collisions with the world geometery handled?  Do you create a bounding box / sphere for every polygon and then test against the world bounding box / spheres?Assume the map is small and I don''t feel I need to add quad / octrees. 
  It depends on. What kind of terrain do you have? A single courved surface? Tile-based? A complex tarrain consists of several small objects. If not, and the terrain is threated as one big object, simply use some space partitioning: put the terrain into a quadtree/octree. The simply call the special terrain-to-object collision detect, that uses this partitioning. Got the idea?   "Knowledge is no more expensive than ignorance, and at least as satisfying." -Barrin ;  The terrain is comprised of about ~512 triangles to form a the hills, valleys, etc.  Its modelled in a simple terrain editor that can export to the map format I''m using.I don''t really want to break the terrain up using an octree / quadtree just yet, I still have many things to do before this.  Is a tree the only method of collision that I can use to effectively check collision?ie, am I forced too? ;  if you have a heightmap for your terrain, then you don''t need tosee this thread. ;  Its not a height map.  Its formed terrain, something you could model in WorldCraft / Radient.  It could form a Half-Life / Quake style level if I so chose.  For now its outdoorsy terrain.Right now my World class stores a list of all triangles / quads and nothing else. ;  then you''re boned. To do it in an even relatively efficient manner, trees are the way. Although, 512 tris is well within real time territory. and you don''t need to break up the terrain, per-se. you just build a tree around it, and reference triangles in leaves. my preference goes to loose AABB binary trees (that''s a mouthful). Especially good for well balanced data sets, like a terrain. no bullshit, easy to implement, fast, you can compress them to 11 bytes per branch, for extra kicks.  