[LDCad] Concave collision detection

[Stefan Frenz]

by collision detection alone

I tried collision detection with the mesh triangles for LDInspector, and it's not too easy to have an appropriate tolerance band. If I just calculate intersections between triangles, it works in most cases, but as soon as rotating or not-rectangular-angles come into the game, the tolerance band has to be adjusted and some cases are "not solvable the easy way". Consider the attached example: two pieces with "round" shape, in green perfectly aligned and in orange rotated by 5° which produces three "false positive" intersections.
  Example.jpg (Size: 7.01 KB / Downloads: 37)

I also tried the quickhull algorithm. Maybe this would have been useful for checking multiple times, but as LDInspector checks all objects only once and not multiple times, it's not used anymore there.