I'm working on a system that requires a deformable surface. That is to say a surface I can carve into. I'm having a hard time finding a starting point for research, hopefully just because this type of surface has a special name I don't know.
My current surface is a simple triangular mesh. When I position the mesh in the world space it is aligned so that it's normal is parallel to the most common direction of carving. I then have a sphere I can fly about which does a hit test with each vertex on the surface. If a hit is positive the vertex is moved away along the surface's relative normal.
This worked quite well but as the project expanded the surface limitations became a problem. As the vertex motion is only along the z-axis I've only produced a 2.5D surface. I now need to be able curve the surface around on itself. Also I need to be able to tunnel into the surface making a full 3D surface necessary.
If anyone can offer any help I'd really appreciate it, even if it's just a search term, as I've had no luck so far.
I don't know if it helps, but when I hear "carving into a surface" I immediately think of Constructive solid geometry. (An an OpenGL(R) CSG library called OpenCSG).
Regarding the sphere-cursor surface deformation, I've seen something like that implemented in Ogre3D. (See here, not sure if that is what you meant, but sounds like your description)
Thanks for your reply, they both look quite promising. The video at the bottom of your last link pretty much shows what I'm after.