Hi Chris,

> Not sure why you would think it would melt it.....

Well, try hypernurbing a cube and you will see it greatly change shape, melting down to a kind of ovoid shape similar to a sphere.

Just in general the action of applying sub-d smoothing changes the shape of things like that.

You can reduce the amount of change by having more polygons that don't have very sharp angles between any pair of them. But the shape change is still present, so like I mentioned previously things like vertices that used to be perfectly arranged in a circular shape will not have the smoothed results exactly arranged in a circle anymore.

It's also quite easy for ripples or lumps to be formed in the sub-d result in response to some kinds of topologies. See this video for some examples of that kind of stuff:
http://guerrillacg.org/home/3d-polygon-modeling/subdivision-topology-artifacts

So it's quite possible during this conversion process that some kinds of ripples and bumps will get introduced into what was previously a very exact and smooth NURBS-generated model.

Applying sub-d smoothing does not just automatically "improve" a model in all cases, it modifies the model and the modification is not guaranteed to be always good. Particularly if you had the model in its proper exact shape already (which is frequently how NURBS modeling works - the basic functionality of NURBS modeling involves making exact geometry, things like perfect spheres, carving precise holes in things, etc...), you would not want to apply sub-d do it because you would then mutate it.

If you want things to be kind of melty/lumpy then it's certainly fine, but if that's what you want then you probably should be using a poly modeler to create those types of models from the start. MoI is generally better suited and designed for making models that are well defined by profile curves, it's not focused on melty lumpy type model creation.

- Michael