Quote:There must be a way to use the SAT to find distance to collision for 3d convex objects as well, yes?
Yes. The principle is the same, but whereas in 2D the axes to test are simply the normals to the edges, in 3D they are the normals to the faces, as well as the cross products of each edge from object A with each edge from object B.
SAT is invariant under axis length and sign (i.e. v and -v are equivalent). So for, say, oriented bounding boxes, where edges and face normals are colinear, the number of axes to test can be reduced considerably. For arbitrary polytopes, however, the number of edge cross product tests required can be prohibitive.
Also, as Christer mentioned, 3D introduces the problem of degenerate axes resulting from near-colinear edges, and the resulting numerical problems.
