I've seen a similar trick in numerical analysis. You add an fourth dimension to a computation grid and it reduces numerical problems with the 3D computation. I dont know if there is a name for this trick.
There is also a trick (read: algorithm) in computational geometry that computes (2D) Delaunay triangulation by mapping the points onto a (3D) paraboloid, and then computing the convex hull of that. E.g.: http://i.stack.imgur.com/OuWmZ.png
