Hi Andy, a sub-d polygon modeling program is much better suited for modeling a head than a NURBS modeler.

The big problem area is that NURBS surfaces have a regular grid layout to them with a set number of rows and columns in it. That means that a single individual point can't be added into a surface, instead an entire row or column of points has to be added. This makes it difficult in areas that have small details like especially around the nostrils and ears.

Sub-d modeling was basically created to solve this problem and to make it easier to model organic shapes exactly like heads since in a poly modeling program you can add in a single point instead of a whole row or column.

NURBS modeling has its strengths in different areas, especially in man made mechanical objects where the NURBS mechanism for having "trim curves" on a surface that mark different areas of it as active or as holes. That's the foundational thing that makes booleans work well in NURBS modeling.

So it's basically a matter of different tools being suited for different kinds of models. A head model is very much in the polygon sub-d modeling area and not in the NURBS modeling area. For a mechanical part it's the reverse and it's much better done in a NURBS modeler.

There are some kinds of shapes like vehicles that are in a kind of gray area between these zones. But a head is definitely not in a gray area, I don't recommend trying to use MoI for that type of use it's not going to work well for that purpose.

- Michael

Hi Andy,

re:
> I was hoping the base Moi model would give me the tensioning / support shapes - hoping that by
> creating a cloud of lines that follow the main flow lines of the individual elements, that MOI would
> then be able to stitch together in a fluid flowing surface

Unfortunately it just does not work out like that. There is too much variation in shape as you move around a face. When you try to incorporate a localized feature like the nose, the effect of the shape change will tend to stretch out along the row and column structure of the NURBS surface.

NURBS surfaces work best when they form broader curved sheets without any small scale "high frequency" bumps or lumps within an individual surface.

When you use the Network command for something like that it's trying to make one single surface that has too much going on within it.

I strongly recommend not trying to use MoI for that work. It's theoretically possible - people did use NURBS modeling for that back a long time ago before sub-d modeling was widely available but it requires an extreme amount of practice and labor and it's ultimately just not a good fit.

- Michael

Thanks Michael / all for your most helpful comments