2.5D Relief carvings ?

[Steven L.Patterson]

I am trying to do some 2.5D relief carving and read in the SB manual that it could be done by shading an object. I have tried to use variations of radial shading in both Corel and Adobe but instead of a curved surface on a test "ball" shape I get a cone shaped surface. I suppose that this is due to them using an equal stepped shading from white to black instead of thighting up the shade steps which would create a true sphere shape. Am I barking up the wrong tree???
Do I use a different method or program? Who might have some experience in this realm?
Thank you, Steve