   Triangle to Triangle Collision
  I have been trying to find something good on triangle to triangle collision but the only real thing I found has little documentation but actual code. http://www.cs.lth.se/home/Tomas_Akenine_Moller/code/opttritri.txtIs what I found but I just do not see it visually how that works. Could someone explain triangle to triangle collision? I tried everything (including http://www.realtimerendering.com/int/ ) but I just can not visual it.   
  There are a lot of cases that need to be handled when doing triangle-triangle collisions.  Check out page 24 of this paper: http://www.geometrictools.com/Documentation/DynamicCollisionDetection.pdf