I'm still trying to find the best technique for doing this, so this model has various anatomic flaws. Its very much a work in progress with a lot still missing.
Still, it shows that it is possible to do organic modeling in MOI. Crits and comments welcome.

I have some ideas on how to make this kind of modeling much faster and easier in MOI than it is right now.
But I think I'll wait until I've nailed the exact right technique for doing this before I start throwing feature suggestions about. =)

Hi curveman, that's a good looking result!

It certainly is possible to do this kind of work with MoI but I think it will take you more time overall to do it than if you use a polygon/sub-d type modeler.

This stuff just isn't really the focus of MoI's toolset. A sub-d type modeler has a lot more focus on making adjustments to smaller more localized areas, which can really make this particular type of modeling a lot easier.

- Michael

T-Splines for optimal modeling control with machine precision

http://tsplines.com/t-tools/

"The T-Spline technology addresses some important limitations that are inherent in conventional NURBS surfaces. T-Splines are based on solid mathematical principles. An important practical consideration is that T-Splines are forward and backward compatible with NURBS."
--Dr. Rich Riesenfeld, Pioneer of B-splines in CAD

Ill pay any price to have it in moi, pls consider it.

I don't think fancy gimmicks like T-splines are necessary for this type of work. My model is made from simple lofted curves running down the head and I've had no problem adding extra control points
where more definition is needed.

What would have sped this up a lot however would have been

1. a standard translation widget and XYZ axis lock to make it easier to push points in the right direction
2. a control point slide tool that lets you slide one or more control points along a curve

>> This stuff just isn't really the focus of MoI's toolset. A sub-d type modeler has a lot more focus on making adjustments to smaller more localized areas, which can really make this particular type of modeling a lot easier


I started doing it because I wanted to NURBs model a robot with a mechanical body and a human face. It was a little hard to get the hang of at first but now I'm starting to see benefits to doing it in NURBS. It really lets you design the facial features without wrestling with topology (subDs) or working with putty (Zbrush/Mudbox). I'm actually enjoying it more than messing with polygons.

Small update. Started modeling the inside of the nostrils and adding some definition to the face. The model has become more male in the process of resculpting the nose and mouth area with extra curves. The loft is also holding up pretty well considering that the control point count on the curves has become irregular and the control points don't line up horizontally as they did before. I'm using the "loose" option with points set to "auto".

btw, this is the first time I've modeled a head using NURBs, ever. I'm kind of excited that its working OK so far.

I agree, I also feel you can get some decent head models using NURBS just as you've shown - at least a base mesh that could be take further elsewhere.

Hopefully Michael will consider adding the point editing tools you've mentioned since they would obviously help with your workflow along with other curve editing chores.

-Will

I'm doing the face partly to get a better feel for creating NURBs designs with arbitrary curvature. I made this using the conventional "draw in 2D and loft/extrude/bevel" method
and realized doing it that I have to get more practice at constructing arbitrarily shaped freeform NURBs surfaces if I want to be able to create designs with more elegant lines
and contours.

The human face project is my entry point into the realm of "no fear" NURBs design. =) Its already given me a much better sense of how certain kinds of designs that I know how to
do with subDs can be realized in MOI, and it feels liberating. Good to push yourself this way every once in a while.

Hi curveman, the human face is definitely a great exercise for freeform shaping!

In the future MoI's toolset will generally cover more stuff and it should get less painful to do more freeform stuff. But it will take a fair amount of time before this really gets fully going though.

For MoI's early versions I have focused more effort on providing a toolset for the kind of industrial / mechanical type forms like you show in your image directly above. One of the reasons for this focus is that there isn't really anything else out there that targets this kind of modeling in a more artist-friendly way rather than an engineer focused way.

There is still some more ground that I want to cover in the "industrial form" kind of area before really digging into attempting more totally organic freeform stuff.

I guess it just seems to me that subd tools are handling the fully freeform area pretty well already. It's kind of less interesting (and just less useful to a wider set of people) for me to focus on stuff that is already being covered by some other tool, at least for a while.

- Michael

Hi Curveman,

Nice job so far. I will follow this thread as I'm interested in NURBS organic modeling too.
Please post your findings (and tips) while you develop your techniques...

Cya

I like the industrial design capabilities of MOI a lot and I'd also like to see improvements on that front. MOI is better suited to that kind of modeling than any subD or poly modeler I've tried
and things designed with MOI are CAD accurate and go out to manufacturable formats like STEP/IGES - huge plus.

I'm fascinated by the idea of being able to do both organic AND industrial modeling well in the same modeler however, so I'm trying to work out a workflow for doing organics in MOI
even if it isn't expressly supported with tools made for that purpose at this point. There are some possible industrial applications for NURBs humans - high end medical simulation, placing reference
humans inside CAD designs to get a better grasp of ergonomics and safety issues and so on. There are also CG renderers capable of rendering NURBs surfaces very quickly, like Pixar Renderman.

The loft algorithm in MOI is pretty robust. I'm using it with "loose" and "number of points - 17 points" and the model surface updates in maybe 500 - 600 ms when I make a change,
despite the huge number of (mirrored) curve points I have now. Realtime would be better but its good enough to work with.

oh, and rejoice. MOI has just joined the "can do butt ugly, wrinkly characters" club started by Zbrush. =]

> MOI has just joined the "can do butt ugly, wrinkly characters" club started by Zbrush. =]

Ha! :) That way you don't have to worry about any ripples and undulations from the loft, they just add more character in that case!

Before subd became mainstream it was a lot more common to do faces using NURBS. I think someone posted Jeremy Birn's tutorial and there are some other ones floating around, like:
http://highend3d.com/maya/tutorials/modeling/nurbs/156.html

One technique that used to be commonly used was a kind of radial layout of cross-sections around the mouth (shown in the above tutorial).

Another method that I see sometimes used is a kind of hybrid NURBS / Polygon approach where different individual pieces are modeled using NURBS tools like a sweep for a top cheekbone, or most of a nose, but you keep all the pieces separated with some space between them and then in the poly modeler add polygons to connect the pieces together.

- Michael

I just knocked together a very quick and dirty tutorial for getting a face from a poly modeling or polysculpting software to MOI NURBS model. Sorry that it turned out a bit ugly. Only have GIMP installed on this machine so it was a monumental struggle to lay this out. =P

This is more or less how my head started, even though I completely resurfaced it a couple of times with new curves.

This could actually be semi-automated in the obj23dmwireframe tool if it automatically deleted any edge more vertical than say 45 degrees to the horizontal and just left the horizontal edges useful for curve creation. A choice of horizontal or vertical lines wouldn't be bad either.

Hope some of you find this useful, even though it is annoyingly manual.

>> Another method that I see sometimes used is a kind of hybrid NURBS / Polygon approach where different individual pieces are modeled using NURBS tools like a sweep for a top cheekbone, or most of a nose, but you keep all the pieces separated with some space between them and then in the poly modeler add polygons to connect the pieces together.<<

Dassault Systemes seem to be using a subD/NURBs hybrid modeler in their Imagine and Shape product

http://www.youtube.com/watch?v=RwOuaNvpPLI

It looks like a subD control cage being used to a drive a NURBS engine.


I would personally love to see a voxel based freeform foam/gel modeler driving a NURBS surface engine or some kind of metaballs -> NURBS modeler for organic stuff. One can dream, heh heh. =]

Hi curveman,

> It looks like a subD control cage being used to a drive a NURBS engine.

Yup, it's pretty interesting! And only something like $10,000 to buy...

From what I can tell, the modeler itself is all sub-d and then the interesting part is that it has the ability to convert the Subd surface into a set of stitched together NURBS surfaces that can then be imported into their regular NURBS CAD tools.

There is actually a pretty close relationship between the Catmull-clark type subdivision surfaces and NURBS - in fact when you have a very regular quad layout (with each mesh vertex having 4 edges coming out from it), there is a really easy direct conversion possible between Catmull-clark subd and NURBS.

It gets much trickier where there is a non-quad layout. In those areas there isn't an exact conversion and instead something has to be done that calculates a kind of fitted NURBS approximation in there.

Maya actually has some similar conversion tools built in, although they don't seem to have gotten much development for quite a while, and T-splines on Rhino is the other recent thing that is pursuing this kind of Subd + NURBS hybrid approach.

In the future I think this kind of combination will get to be more common.


> I would personally love to see a voxel based freeform foam/gel modeler driving
> a NURBS surface engine or some kind of metaballs -> NURBS modeler for
> organic stuff. One can dream, heh heh. =]

That's a lot more difficult because at least with Sub-d there are a lot of areas that have the exact conversion.

With these other types, there is no exact conversion anywhere, so the entire thing has to go through a kind of fitting / optimization type process.

There are some types of "reverse engineering" type tools that are set up to do this kind of processing, for example check out geomagic.

- Michael

Hi Curveman - It's very interesting and thanks for the quick guide.

I'm a rhino user so I think I can approach to MoI a bit easier than other tools. Even the functions in MoI are not so many as Rhino but I think that some of functions in MoI are stronger than the Rhino or other tools.

I couldn't withstand temtation of MoI and I'm enjoying it. :-)


Thanks,
momso

Hi Momso, I'm glad you're enjoying MoI!

One quick note - it is easy to use MoI and Rhino in combination with one another, you can share data back and forth using Copy and Paste between them, you don't even need to save to a file.

- Michael

Michael,

Thanks for the tip. I didn't know about it, so I was save as .3dm file and open it in Rhino again. It's cool for using copy and paste in between MoI and Rhino.
As you said, even official release is not so different from the current beta version, but I'm waiting for coming it out .

/momso

>> That's a lot more difficult because at least with Sub-d there are a lot of areas that have the exact conversion.

>> With these other types, there is no exact conversion anywhere, so the entire thing has to go through a kind of fitting / optimization type process.

There's all sorts of clever ways to go from unstructured stuff like voxels to NURBS without necessarily getting into super complex fitting algorithms. Here's one "cheap and dirty" =) way I can think of doing it.
This method would run into problems when a model has a hole or cavity that goes from one side all the way through to the other, or with something like a tree where things branch off from the main trunk and need to be handled separately. But even that could be fixed with a bit of clever coding I think and the user himself could be tasked with segmenting or color coding the voxel volume so that it can be parsed easily by the NURBS conversion algorithm.

I think this is one potential method for creating a bridge between truly 3D freeform sculpting that feels like shaping things with a soft modeling foam or gel, and more structured NURBs modeling. It would be enough if you could rough out a 3D organic shape quickly with a voxel brush/nozzle and get an "OK" quality NURBs model or set of curves out of it that can serve as a guide for the construction of a cleaner, better defined NURBS model.