One of the things I'm ultimately hoping to do is learn Moi well enough to do some of the high detailed ships/vehicles similar to the stuff that Daniel Simons has turned out (see http://www.cosmic-motors.com/main.html for example). In his book Cosmic Motors, he mentions that his workflow is a NURBS modeler, and then texturing/rendering in Maya.
So, being a naive newbie, I thought, OK, why use Moi as the modeler, then move it into the 3D package of choice for texturing/rendering. I've got Modo, I've got Houdini, and I've got Maya. I have a fair amount of experience with Modo and Houdini, but only a little with Maya, so my initial preference is for Houdini, if possible.
I know how to get things into Modo - use the LWO exporter, and Bob's your uncle. Job done.
Getting things into Maya/Houdini seems like a different challenge. Since both support the IGES, and both support a full (or close to full NURBS toolset) I figured that it made sense try using that. I tried this with my light cycle engine model. Both could import the iges file. Houdini got *really* sluggish, as did Maya, and it didn't seem like it would be very practical to work in that format. Selection was difficult because there were so many different little pieces.

So what is the preferred workflow for other packages? Is it better to stick with obj/lwo format? Or is it expected that if you want to work in NURBS that you have to go to a lot of trouble "reworking" the model after it's exported?

I use Modo to render MoI models. One of the main reasons is that if you want to change your model, you can do so in MoI and re-import in to Modo without losing all your shader settings and material allocations. Not as easy in C4D or other apps. Keep your material allocations in MoI as named styles. These will transfer into Modo as material allocations. The second time you import, a new group will be created which you can delete and the allocations revert to your Modo materials you set before. Keep the names the same as the MoI styles, for this to work properly. I have got it to 2 clicks on re-import to get where I was before.

Hi Jim, even though Maya and Houdini both support NURBS and the IGES format, they are not really very focused on handling it. In practice Maya users for example use OBJ format and polygon data much, much more frequently.

So even though they technically support it, it is an underutilized and less refined area of those programs, and it's probably best not to rely on it.

NURBS data is something that is more strongly supported in CAD programs, and it is not as well supported in animation programs just in general. In various animation programs their NURBS support is old and has not had many resources devoted to fixing it up over the years. They've been much more focused on sub-d modeling for quite a while now.

Maya, Houdini, Softimage, and 3DS Max are all kind of similar in this aspect.

For these particular programs you should get better results if you export polygon data in OBJ format (or FBX for Max) instead of trying to use their native NURBS functionality. For Modo or LightWave use LWO format.

- Michael

Thanks Steve for making me head over to the Modo website to learn so much more.

Hi Jim,

If I remember right, I get nice result in maya using the *.step/*.stp format.
We were using renderman at that time, so the tesselation was just perfect.

Stay away from IGES, it's old and doesn't work well even though Maya/Max support it. No one can agree on how to handled trimmed surfaces (128) and you end up with a lot of orphan patches etc.

STEP is good, but my experience in loading this format to Maya/Max isn't good as they still don't seem to treat the surface patches consistently. Especially if what you want to import is an assembly of components.

Normally I'm using Okino with Maya to direct import and tessellate.

Bummer. So from a practical standpoint it seems that you just stick with exporting polys. Not the end of the world. I'm kind of surprised that things are so creaky on this end. Working in Nurbs has been a pleasure so far for hard surface stuff like vehicles. I can't imagine wasting the time hassling with subds after this.

You really need to test it for yourself. I tend to deal with large assemblies, not small discrete part subsets. I've seen people use it but the other downside is getting it out of Maya while it resides in Maya as NURBS is horrible. It literally breaks up all the surface patches and you end up with 1 object per patch.

Hi Jim,

> I'm kind of surprised that things are so creaky on this end.

The problem is that animation programs largely abandoned NURBS back around ~15 years or so ago in favor of sub-d modeling (which is better suited for stuff like characters/faces/organics stuff like that), so their support is kind of vestigial and was never really driven in such a way to target the best strengths of NURBS in the first place (mechanical / hard surface modeling).

That's why you can find a lot of discussions in animation forums about avoiding NURBS and "NURBS are useless", etc.. etc... - a lot of those people just don't realize that their animation-oriented tool only has kind of half baked and undeveloped NURBS support, and then they judge NURBS modeling based on that.

But yeah if you use it for the right kind of model (mechanical, generally man-made things, things with holes and cuts in them, ...) a NURBS toolset that tries to generally target those strengths can be great.

- Michael