Michael,
I bought an academic copy of MOI with the expectation of using it to build and/or modify 3D geologic interpretation grids. Then using the interpreted 3D geology surfaces I can model the gravity effect of the expected geology interpretation; though I must confess that I haven’t had time to implement any testing yet.
I've attached an image of an interpreted surface of the crystalline basement created using a gridding algorithm that takes faults into account; but there are no programs that allow for simple free form modification of the gridded surface. One of the unique features of geology are discontinuities and faults, therefore geology surfaces are piece-wise continuous with faults and geologic parameters define boundaries between the areas of defined surfaces.
I realize that this is not the conventional use concept of MOI but I am hopeful that you can give some feedback about the concept and/or assist me in the development of one or more workflows to integrate/synthesize and modify geologic data and digitized expected surface interpretations. I believe an implementation of constrained “free form” surface modification would aid geologic interpretation techniques.

Kevin.

Since I pretty much do not know what you are talking about :-)
do you have any web references than would help to educate me?

Are you looking at surface topology/topography, or the result of subterranean geology?

There is GIS software out there...

- Brian

Hi Kevin,

> I realize that this is not the conventional use concept of MOI but I am hopeful that
> you can give some feedback about the concept and/or assist me in the development
> of one or more workflows to integrate/synthesize and modify geologic data and
> digitized expected surface interpretations.

I can try to help you, but my first reaction is that you probably need a more specialized kind of tool that's more focused on terrain handling to do that kind of stuff.

MoI is just not focused at all on many of the things that I think you'd need for this project - the overall modeling mechanism that it uses (NURBS surfaces) are more oriented towards man made type objects, stuff that generally has more broadly curved surfaces and not high frequency bumpy details in it. Usually shapes with that type of details in it are done using triangle mesh models and not NURBS surfaces. MoI is focused only on modeling using NURBS surfaces and not doing triangle mesh modeling, so it may just not be the right tool for the particular job that you require...

- Michael

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