Just made this .obj import script for my subdiv project.
It may not work with complex models, but it's better than nothing.

Seems works fine!


But what will be the process after ?
It's like an import import image as background for modelize something but in 3D ?

With Moi I tend to work the other way around where I model the nurbs part first and export to mesh, then open modo and finish it off.

Another program that imports meshes well is ViaCAD Pro. The new version 9 also includes some basic mesh and subdivision modelling tools.
He is also about to release a Powerpack addon http://www.masterviacad.com/powerpack/powerpack.html that will also allow you to convert your sub'd meshes to nurbs surfaces which is a pretty awesome addon. All up the cost of both together will be far less than Rhino, let alone Rhino and TSplines.

Hey guys, I used the search because I do not want to open a new topic.

I made a small tutorial that describes how to export marching cubes models from MagicaVoxel to Moi3D for Rapid Prototyping in Moi3D -> http://www.8bit-labs.com/article_t/3/
The interesting point in that story is that I use a dirty (not optimized) polygon mesh natively to generate a waterproof solid in Moi3D by doing 2 Boolean operations.
You can read the details in my tutorial.
Here is an image of the process in Moi3D and a short version of the description (Moi3D part) ...

1 Import obj file in Moi3D [4], select all faces and join them via join command.
NOTE: in the original tutorial I use a step file from Solid Edge. I generated that step file based on an obj file that I imported to Solid Edge before to export it as step file because Moi3D can import them out of the box. This step file is dump, means all faces are polygons itself. You can see it in [4]. Frenchy Pilou already gave me session on Discord that I can import obj file by a script of Max to Moi3D ;) .
2 Construct a solid box around the whole imported step/obj model.
3 Select the solid box, hit Boolean operation ‘subtract’ and use your imported model as ‘objects to subtract’. The result is a solid box that encapsulates empty volume corresponding to the imported model [5].
4 Construct a 2nd solid box, select this one, hit Boolean operation ‘subtract’ and use your result from the 1st Boolean operation as ‘objects to subtract’. The result is a solid model [6] of your original export from MagicaVoxel.

I wanted to share this small work around because I was really surprised that it is such easy to transfer a polygon mesh to a solid body in Moi3d; and such robust.
Thanks for your time and have fun!

;)
Cool...
Ok i have a little one other :)
- Export in PLY "Marching cubes" from MagicaVoxel (free) to Mesh Lab (free) - Export in OBJ format
- Import OBJ mesh inside SketchUP 20217 Make (free) by OBJ Plugin by Tig (free) 10 seconds
(import directly OBJ in Moi is not good because there are thousand of little cubes with no Ngons (triangulated) ! :)
- Clean Up plugin (free) by Thomthom = Ngons 3 seconds
- Export OBJ Format from Quad Face tool (6 seconds)

Import in Moi with 8mportOBJ ( object is not "Subdivisable" but totally perfect as Nurbs object ! )

Object on the left is from Magicavoxel after the process above!
( object itself in MagicaVoxel take maybe 3 seconds) it's for that this program is a true gem!

Object on the right is just a Moi Nurbs function applyed


and then with a moment of Inspiration with the object on the right :)


Export file formats from MagicaVoxel (free)


So if a direct importation to Moi will be possible that will be very fine! :)

Else discover the speedy Blender (free) Method! (with some hairs losted...this prog is a mess) :)

Import OBJ (no "Marching cubes" ) from MagicaVoxel : Select the Object ..Edit Mode / Face .... Press F
.
that all : triangulation is gone ... you can export ! :)

_importOBJ by Max Smirnov for MOI
You have a solid (no subdivisable) perfect for nurbs operations!



Some moments of inspiration later! :)

PS Find the ultima Blender Method : a nightmare for find the good process!
- merge by distance - unlimited disolve - clear custom split normal data!

Woks fine directly inside Blender for OBJ or PLY (Marching cubes) in one pass!

Thx to LOLock
https://i.imgur.com/LceY8nu.mp4

So in MagicaVoxel you make this volume in 1 second!
And can of course modify it in Moi3D (if wanted) by import an OBJ without triangulated faces!
_importOBJ by Max Smirnov