Don't try and apply sub-d in Modo. There is no need and it won't work properly.

Thank you for all the help and great tips Michael. That looks great now.

SteveMacc,

Yeah, getting a meshed model that can be sub-d is tricky. The problem with leaving it as plain polygons is that while the vertex normals will smooth the look of the surfaces, you can see the polygonal shape on the edges sometimes if you view them from the right angle. Right now I'm experimenting with getting meshes from MOI into MODO. Hopefully if I build the model right in MOI I can avoid having to sub-d, but I'm not sure that will always be possible.

Right now this model looks good when I render it whether I sub-d it or not, so I'm inclined not to.

Hi Sun - re: polygonal silhouettes - the main method to eliminate those is to increase the density of the export from MoI, you can just move the slider in the meshing options dialog towards the "More polygons" side to produce a finer mesh with more polygons in it and no other work will be involved.

Trying to do a sub-d refinement of the MoI generated mesh on the other hand is going to involve quite a lot of additional work because sub-d smoothing requires a particular kind of polygon topology to work well. MoI generates a kind of sparse efficient polygon topology that resembles the original NURBS model and it's a totally different kind of topology than what sub-d actually needs.

Here's a quick example object to help illustrate it more clearly:



So note there that MoI's mesher generates a single planar n-gon on the top there, which matches the original object which had just a single planar surface for the top face. That's a great result for getting a clean and efficient polygon structure for uv mapping or rendering but it's very very different than the kind of topology that you need for sub-d smoothing.

For use as a sub-d cage you would want that top piece to be tiled into a bunch of quads that radiate out from the outer edge and try to have some good organization where they then collide into each other. That would mean generating quite a lot more little polygons for that case than what MoI's current mesher does, and it would mean producing the mesh in a completely different way.

So it's generally not feasible to apply sub-d smoothing to polygon output from MoI expect in some special cases. If you want to apply sub-d smoothing you're probably better off creating the polygons by hand because then you'll be able to control the specific kind of topology that is required for the sub-d smoothing - either that or you can use a retopologizing tool like TopoGun or some of the tools in 3D Coat but you should expect to have quite a bit of work and effort involved in doing that.

Meanwhile for making a denser mesh when exporting from MoI only involves moving a slider over a bit so that's a couple of seconds of work as compared to a huge amount of work for re-topo and then sub-d smoothing.

- Michael

Yes, I've been experimenting with the various meshing parameters to come up with something that doesn't need to be sub-d, or if that doesn't work well, will sub-d in an acceptable way. I know that making a mesh suitable for sub-d is going to be tricky, and may require some editing in modo.

My own experience with Moi to Modo is that if you set the mesh angle to 6, you will not get any faceting in Modo. You can then adjust the other parameters to reduce the poly count. "Smaller Than" is a useful one where you have small fillets. The rendered poly count is similar to a mesh constructed in Modo with a subdivision level high enough to avoid faceting.