Hi Michael and Max,

i just recently discovered an open source solution, based on the FreeShip
software, available at Github, which allows one more or less to convert a
subd mesh to a NURBS model. While this solution somehow works, the
final model is however not stitched and there are some areas which needs
to be reworked. Anyways i thought to show this to you, so that maybe it
could lead in the future to an easy? subd to NURBS solution for MoI.
Compared to Max's solution this one has fewer patches and not like for
every polygon a patch.

https://blenderartists.org/forum/showthread.php?412430-From-Blender-Subdivision-To-N-U-R-B-S-(IGES)-for-free

Best regards
Stefan

Does this the last workflow ?

The steps to convert:
1. Export from Blender in OBJ. (or from any subD modeler)
2. Convert from OBJ to VRML1, with Meshconv. (Command line for Windows) **
3. Start FreeShip, and import the VRML1.
4. Export the file to IGES (NURBS).
5. Start FreeCad and then open IGES file and export it, to IGES or other formats NURBS, Moi3d does not open the file exported by FreeShip.

https://www.freecadweb.org

http://www.patrickmin.com/meshconv/

** Meshconv usage: meshconv -c wrl -vrmlver 1 blender-file.obj

No more recent FreeShip or easy install than https://github.com/markmal/freeship-plus-in-lazarus/releases ?

Hi Pilou,

yes, because it requires to import in VRML 1 and the IGES export is not
compatible with MoI, hence the usage of FreeCAD, to get the model
into MoI.

Best regards
Stefan

Darn, no Mac OS version of Freeship. I could very much use this tool in my workflow.

Stefan, I thought you're a Mac user like me. Did you run this on a Windows PC, or am I wrong about a missing Mac OS version?

Anyway, thanks for the tip.

Hi,
it's possible to translate ".obj" to ".wrl 1" only with Freecad.
Open ".obj" mesh in Freecad into Mesh workbench, select mesh and save to "#Inventor V2.1 ascii".
Open file "#Inventor V2.1 ascii" with notepad or other and change the header from "#Inventor V2.1 ascii" by "#VRML V1.0 ascii".
Open file .wrl 1 with FreeShip.
Enjoy

Hi Metin,

yes i'm a Mac user, but i have also a Windows/Linux Notebook.

But i quickly tested FreeShip under Wine and compiled
the mesh converter under OS X. When running FreeShip
under Wine the top graphics? buttons are black, but one
can still convert via the menus.

P.S. don't expect to much from the converted NURBS models...
I only wanted to show a possible solution for Programmers
like Michael and Max etc. to maybe get an idea of how this
is done with FreeShip, because it's OpenSource.

Best regards
Stefan

Hi Stefan

Unfortunately, this method doesn't support surfaces with extraordinary vertices. Using FreeShip you can't create nurbs surfaces with smooth transitions across edges.

Hi Max,

thanks for looking at it and explaining to us!

Best regards
Stefan

@ Stefan: Thanks for the info. I guess I'll stick to Max's subdiv tools for MoI.

@ Max / Michael: If you could build something like this for MoI, I'd gladly pay an extra sum for it — http://masterviacad.com/powerpackoverview/PowerPackPro/page36/page36.html

Here's a video:
http://www.csi-concepts.com/Demo/videos/objToSTEP.mp4

The main difference with Max's current subdiv tools is that not every quad polygon is converted into a NURBS patch, but the patches are generated based on curvature and detail level, resulting in relatively lightweight, uncluttered solids. T-Splines works that way as well.

Hi Metin,

i did a test with Max's subd script and the merge command in other software. I could bring down
the file size from 10 MB to 5,7 MB. Now i must find a way to replace the 3 and 5 edges pole areas,
because merge does not work well with them. If we had a least something like merge in MoI then
we would have a good start with MoI and Max's subd script, i would say. This is of course a time
consuming process, but IHMO worth to explore more.



Regards
Stefan

Hi Stefan,

Interesting!

A few questions:

1: How did you get the nice all-quad topology on the Stanford bunny?

2: Which tool did you use for the merge command?

Thanks,

Metin

Hi Metin,

the quad mesh is auto retopo from 3DCoat or was it ZBrush (trial) ZRemesher,
i did years ago. Can't remember wich one i used...

The merge command i used is from ArtForm Pro 4.0 NURBS Modeler module.
But i think others like Rhino etc. have a merge command too.

Regards
Stefan

Thanks Stefan!

Have a nice Sunday,

You're welcome Metin.

Have a nice Sunday too!

Best regards
Stefan

I really hope/pray Max will find the time and will to work on the surface simplification from his amazing subdiv script. The work he did on the surface quality was (is) amazing !

Maybe it could even become a native MoI function ?

Hi PaQ.

@You : "...Maybe it could even become a native MoI function ?..."

You hit the crux of the matter :)

We all know that Michael is super super busy right now, but it could be amazing if he could bring the excellent job that Max did with subDiv tools,
into the "core" of Moi (doing a translation the Max's JS code into the native compiled language with which Moi was written)

I think, and I'm sure I'm not the only one who thinks so, that Max's subDiv code "deserve" to be stable part of Moi's core :)

Ciao!

I was under the impression that there still some remaining issues about surface continuity at extraordinary vertices. Is that not the case anymore?

- Michael

@You ".. remaining issues about surface continuity at extraordinary vertices. Is that not the case anymore?"

Well...Maybe you're right but for what I've tested so far I didn't see any issues lately. But I'm not the best person to check this kind of "math" things.

Maybe it's a better idea to ask Max or other "math" guys here :)

Thanks.

Hi Marco,

> Maybe you're right but for what I've tested so far I didn't see any issues lately.

Could you post a couple of the tests?

- Michael