Hi Chris,

> Its clear that there are no tools in the nurbs world (ie. ZBrush)
> for pushing around surfaces like they were clay, but if anyone
> is aware of something that can do this now, please clue me in.

The only thing that really comes to mind is the sensable system: http://www.sensable.com/ although I don't think it pushes NURBS surfaces around directly, it's something like pushing around voxels and then fitting NURBS to it at the end or something along those lines.

Usually stuff that focuses on pushing stuff around tends to be polygon based because it's easier to add refinement to just one area of a model with polygons. NURBS surfaces always have a rectangular control net to them and so you can't just add in a single new vertex somewhere in the middle of a NURBS surface, you have to add in an entire row or column of them when you want to refine it with more points for more displacement control.

- Michael