Shortest distance

Point me in the right direction with this problem since I have no idea on how to tackle it.You're given 4 set of coordinates in R^3 that form a tetrahedron, then another 4 set of coordinates in R^3 that form another tetrahedron.
How do I find the smallest distance from the surface of one tetrahedron to the other?

>>4
Okay, fine. Also project vectors for each point onto the plane of the other tetrahedron. And some other stuff.

In fact, just test each point in the 10 voronoi regions for the other tetrahedron.