   Time an edge intersects a triangle
  I want my collison detection to know when collisions occur so I can ''rewind'' to that point before doing bounces etc. Testing a vertex against a triangle in this way is simple.I could find the plane an edge extrudes as it moves (cross product of edge and velocity) and test the edges of the triangle against this using line/plane tests but it sounds slow to me. I guess I could find the time when the edges themselves intersect instead, what are anyones'' opinions?Speed is important considering even a box/triangle test involves 12x3 edge tests (each edge of box against each edge of tri). 