Hi ado1, could you share that 3D file? That way I can take a better look and maybe I can get you a usable model for your purpose.

Although at this point I have to admit I might not have understood what you’re aiming for by having an STL model imported into SubD, which isn’t possible because of the triangles.

However, if your goal is to have a SubD model in Moi3D, the best thing you can do is re-topologize using mesh modeling applications like Blender, or buy an add-on for Blender, “Quad Remesher”, which costs just over 100 dollars and does an excellent quad-topology reconstruction of 3D meshes, and that lets you import it into Moi3D.

There are issues using those kinds of models directly, though, because Moi3D can’t recognize the sharp edges of subdivision surfaces, so you could still use Blender and other add-ons that let you export the models to IGES or STEP, which take the sharp edges in SubD models into account.

Quad Remesher link -> https://exoside.com/

For example this model below was done manually by me yesterday for a beginner user, and I "retopologized" the model with Blender from a file STL of a laser scan.

Model exported from Blender 3D as STEP file.


Cheers