Hi Keris, yeah I know that looking at the nice clean n-gon wireframes starts to make the gears go in sub-d modelers heads about how they could leverage those meshes for sub-d work.

But it's really a pretty big mis-match... The best example I have to demonstrate it is this simple model here:



Generating a n-gon oriented mesh creates just a single n-gon on the top cap there, which is the correct result to get a minimal number of polygons and a wireframe that follows the original NURBS object structure. It's a very clean result, and perfect for rendering (and potentially non-subd direct polygon editing).

But it's totally not the right result for what you want - you would instead want to have the top broken up into something like a hundred little quads that radiated inwards from the edges. That's not like a minor tweak from the current result, it is a radically different result that is needed.

You're going to run into stuff like this all the time unless you greatly restrict the kinds of shapes that you actually attempt to model in MoI.


> I do think that some of my thoughts on tweaks from
> this post might be of some use;

Well, the problem is that probably some of them would come at a detriment to other situations.

For example:


Here's an example of a NURBS trimmed plane created by drawing some curves and using the Planar command in MoI:



When saving to an n-gon mesh, the mesh result will be like this:




So notice here that every single vertex in this mesh only has two edges leaving from it, so according to what you wrote they should all be deleted and nothing should remain of this polygon?

The problem is that you're not really looking at the entire picture of what the mesher has to do, some of the things that would help for your particular goals are not able to be applied in general because they don't work universally.

One thing that sub-d modelers object to is adaptive subdivision - that's where the mesher changes levels of detail to put some more polygons in an area of a surface that has more curvature.

For example here:


There was a change in refinement level there at the red dot because the surface was going from a flat-ish area to a more curved area. When that happens there will be n-gons generated at the transition points.

It's not generally feasible to not have any adaptive refinement at all, because that would force surfaces that have curvature localized into a small area to get an extremely heavy mesh generated in their flat regions. For example a shape like this:


Trying to do that with no adaptive subdivision at all you have 2 choices - either you get a too dense mesh through the whole thing, or you get too sparse of a mesh through the whole thing and the small feature is not present at all.

So I understand that you don't build things like this, but it is the mesher's job to handle all kinds of situations like this without just blowing up...

- Michael