As a beginner, I can appreciate a challenge like this. So here's the formula: x=10*(u-.5); y=10*(v-.5); z=10-(x*x+y*y)/4; Apparently u and v vary from 0 to 1 (like in UVMapping coordinates), so I had to keep it at u-.5 and v-.5 to get a full surface of revolution. It looks like x and y limit the boundaries, and z is the real equation for the surface.