Converting polygons to NURBS. Possible?

Hello. I have this doubt? I have a scanned head on stl. All came as triangles, then converted to quads. Next step is. I want to convert it to NURBS. Is this possible or I would have to model it with nurbs? Thanks

I want to convert it to NURBS. Is this possible
Not in blender

Which software and how? Would you know?

You have to remodel it. Rhino has good nurbs tools. Blender is better at polys.

rhino has a plugin called rhino resurf, geomagic is other software, rapidform from innus; the last two are the reverse engineering standards. catia and siemmens nx have modules to accomplish that kind of work, solidworks has a dedicated module for this too.

how many quads have the model?; if the topology is correct for animation, you can use plugins like powernurbs or t-splines available for rhino, maya, solidworks, max, modo, etc. this plugins can do the work pretty straightforward, but only if the topology is correct; i mean, do not expect convert an stl file with thousand or millions of poligons. catia has a module for this kind of tool called imagine and shape i think, that kind of tool take a mesh and subdivide it just like the subsurf modifier in blender, then build the patches for every coarse polygon and sew the surfaces.

The metod and the kind of software will be defined for your stl file, quality and accuracy required, feel you free to make any specific question if i was not enough clear.


So Rhino resurf, geomagic, rapidform, catia and nx all can achieve polygon->nurbs? My mesh have 20k-30k vertices/quads, correct topology, sounds like I should try powernurbs or t-spline for rhino, maya, solidworks, max? Which one would you recommend tho? Also it sounds like Catia takes in polygons and subdivide it again then rebuild them into nurbs, but it might end up with way more surfaces than needed.

Also how do you use T-spline in Rhino to turn poly mesh to NURBS tho?

T-Splines has been discontinued.
Rhino version7 (not yet released) will have subd to nurbs.

Fusion360 has T-Splines built in

Subdivided poly mesh to nurbs, Maya already has it built in right?
Is there any other software able to achieve it with good result tho? So far I’ve only seen a visual demo for maya subd->nurbs on a simple cube.

see new Nurbs in blender
there is a way to built it
not certain about an SVN !

happy cl

Look here. By the end of post.

The Rhino developers are working to make it usable; at the moment its lacking a way to optimize the result into as few Nurbs surfaces as possible so it can easily be modified.

I’m not familiar with Maya.

An important requirement to the subd to nurbs process is a way to generate optimized quad based topology from existing meshes. Rhino developers are working on this in parallel with subd to nurbs.

When I used Fusion360 retopo’d all the meshes to quads before I used T-Splines.
At the time I did not know how to use any built in retopo or optimization, so perhaps it is possible without using another tool.
(I used Instant Meshes to make quad meshes to use T-Splines.)
I don’t know that T-Splines forces one to use quad meshes, so there may be a way to use a randomly triangulated mesh.

The monkey demo from subd->nurbs in freecad? Hmm, would be nice if this is completely done inside Blender.

there is also a Dev looking at new Nurbs
so hope it can be added in blender


happy bl

As a long time blender user, I know that it’s better to use alternative open source tricks like that instead of waiting that it ll be cooked inside blender for you. There is to much development points to do before, for the blender team.
I ve spended hours exploring all that hacky stuffs before. And you cannot imagine how much incredible solutions I ve learned with that !

I just tried poly->subd->nurbs in maya, opened it in Alias. It works, but has too many cvs. Let me try your option now. Do you just download the .blend file and the github freecad .zip, and load the blend file into freecad?

No you have to install svershok addon and also the svershok extra addon… and a specific version of free cad… but perhaps this last point is not necessary because of the library’s included in the svershok extra addon… read the end of the post svershok for more info…
I m in a 3d rush for now. Sorry.

Any News on this?

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