Yannada,

Thanks for the .3dm i/o plugin for MODO tip. The existence of this plugin further consolidates MoI and Modo as a powerful modeling combo.

The plugin however only imports and exports polygon meshes.

 

The ability to being directly able to convert between NURBS and SDS is something which much more interesting.

For Rhino users there are 2 different plugins available to convert polygon meshes into NURBS. First there is the T-Splines for Rhino plugin and there is also available something called Smurf or Smurf3D.

http://www2.rhino3d.com/resources/display.asp?language=&listing=93

Smurf just helps you create the patch networks in a semi-automiatic way, but you still have to do it by hand. T-Splines is automatic. And there is also Rhino Reverse, which is somehere in the middle, but has some very interesting features of it's own such as history-updating of the patch network inputs and n-sided patches with very low surface deviation to original mesh...

jonah

Hi yannada,

> Will it read Moi 3DM files? That could be the best combo, Moi for
> nerbs Modo for the rest, SDS etc.

No, I don't believe that it will read MoI 3DM files, because it only reads polygon mesh data from a .3dm file, and MoI only saves NURBS data to 3DMs, not any polygons.

But that's not really a problem - you can already reliably send data from MoI into Modo by exporting from MoI as LWO format.

Exporting by LWO actually gives you more capabilities as well, since LWO supports n-gons while polygon mesh objects inside of a .3dm file are limited to only having triangles and quads, not n-gons.

- Michael

Hi jbshorty

So Smurf works by enabling you to project polylines on a mesh surface and you can subsequenly loft and/or network these polylines and thus recreate the mesh object as an object made of NURBS patches?

By the way, Li Wan-Chiu has written a Ph.D. thesis on the automatic conversion of triangle meshes to rectangular spline surfaces....

Here is the link:

http://alice.loria.fr/php/article.php?pub=../publications/papers/2006/wan_chiu_li_phd_thesis

http://alice.loria.fr/php/article.php?pub=../publications/papers/2006/TOG_pgp

Hope you enjoy,

All the best,

Boatstalker

@ Boatstalker - It's something like that. I don't think Smurf adds any new functions to Rhino. It just creates a little easier time of trying to do the conversion by hand. But it's nothing which you can't do with the native Rhino tools.

jonah

Ops sorry guys I did not notice that detail.Thanks, next time Ill read the instructions first.

Onother question for you masters, Tsplines vs Catmull-Clark SDS ? just your thoughts pls.

Hi Yannada,

T-Splines is forward and backwards compatible with NURBS. That is you can convert NURBS to T-Splines AND vice versa. Basically T-Splines is a specific expression of Catmull-Clark subdivision surfaces but what makes it so beautiful is that it is also a superset of NURBS, thus it bridges these 2 variations of expressing or modeling surfaces.

Modeling with T-splines is basically like modeling with any other variation of CC subdivision surfaces. The advantage of T-Splines is that you can model something with NURBS, then convert the NURBS into T-Splines and continue to refine the shape working in the same way as you were modeling in any standard SDS modeler. Of course the workflow can be reversed in the different direction.....starting modeling something using subdivision surfaces modeling style, then convert the model to NURBS and continue working NURBS style using Booleans, lofting, sweeping and trimming.

So to summarize T-Splines is a pretty cool thing, but unfortunatly it is currently only available as a plugin for Rhino. For those of us who prefer MoI we just have to wait for a while until a plugin for our favorite application becomes available.

.....P.s. one more thing, I just received a copy of an article on extended subdivision surfaces (ESUBS) today, which is some variation of bridging NURBS and Catmull Clark SDS, similar to T-Splines, but haven´t had time to read the paper yet.

But maybe (if we are lucky) we will have an ESUBS plugin for MOI in the future ;-)

an Importer / Exporter Modo / Rhino
http://www.luxology.com/whatismodo/plugins/plugin_rhino_translator.aspx
Don't know if that works with Moi :)

Hi Pilou,

you wrote:
> Don't know if that works with Moi :)

I don't think it will work with MoI since it only deals with polygon meshes and not NURBS - see this message earlier in this same thread: http://moi3d.com/forum/index.php?webtag=MOI&msg=1258.4

- Michael

You right soon posted some posts previous ;)

Hi Boatstalker,

>>Basically T-Splines is a specific expression or subset of Catmull-Clark subdivision surfaces
>>but what makes it so beautiful is that it is also a subset of NURBS



Petr

That's correct. The T-splines people say that it's able to duplicate any nurbs surface exactly, and any catmull-clark surface exactly. This of course must be under the right conditions, and with enough CPU power to handle complex objects. A t-spline is probably carrying more overhead than either Nurbs or Subd...

jonah

Hi Tyglik,

Thanks for correcting my errors. Guess I need to do my homework more properly ;-)

Anyway, for those interested in the topic of the convergence of NURBS and SDS the article on extended subdivision surfaces is higly recommended. It seems like ESUBS offer even more possibilities than T-NURCC surfaces (t-splines).
Here is the link:

http://portal.acm.org/citation.cfm?id=1138455

Happy modeling!!!