From a point to a point, I think. We were talking about mouse picking and polygons and how to get the exact position by using shortest distance. Now that i think about it, though, I guess I wouldn't know the point. I would only know the polygon and be able to find the position of the vertices. Anyway, it was your idea so i was hoping you could explain it again.
Also, what about reproject2d3d? Would that work to find the point of contact?