There are a few tools such as T-Splines or PowerNurbs that allow modification of a nurbs model based on an underlying mesh. Unfortunately, the underlying mesh is quite limited in size. Since your data probably has millions of polys, I doubt that these would be useful. There are also some very high end tools that can convert polys to nurbs, but once you have the nurbs model, you loose the plasticity that is possible with a polygonal model and so I don't believe that will help you either.

So my next suggestion would be to look at some type of polygonal modeler. Many allow you to make a selection of polys and feather the border strength of the selection, so that the selection can be moved and the borders of the selection will move less, or not at all depending on the strength. I believe there are some modelers that will allow you to generate a lower resolution version of your model that you could use to affect changes on the high resolution version.

Hi Kevin, yeah also like Chris mentions above usually polygon modelers have various kinds of deformation tools in them which may also better suit what you're describing as well. In particular polygon modeling systems that are also oriented towards producing animation often have a variety of different kinds of deforms.

That's again just another area where MoI is not really focused on what you're trying to do - the deformation tools in MoI are more limited, and although there have been some new stuff in that general area added for the upcoming V3 MoI release (with new Flow and Twist tools), it's still something that's more focused on more broadly curved or twisting shapes, not really on the kind of stuff that I think you're describing.

So again I think it's very likely that a polygon modeling system is a far better fit for what you're trying to accomplish.

- Michael