Best way to convert/rebuild .stl mesh to Rhino model?

People post many interesting models on However, they are almost always .stl meshes. Is there an easy way to convert to nurbs? I generally rebuild the models completely using the imported .stl as a general template, but something like this with screw threads is more difficult. Especially since I expect there must be a tolerance gap between screw/nut. How much should that be etc?

Hello - convert, no, but an object like this should be relatively easy to reconstruct in Rhino from cylinders or revolved cross sections. The threads will be the relatively tricky part but not that bad I should think.


What I thought. It’s the threads that gave me pause. I actually contacted the creator of the model and he added a .step version I can work with. At some point soon I’ll attempt creating threads. I’ve watched the videos. is a great source for downloading 3d models of many mechanical parts and components, including Metric and Imperial screws, nuts etc. They support the majority of industry standard NURBS file formats. Just select the desired part, click on “Product detail” and then the upper right corner will show a “Save” button to download the model.

I’d used McC in the past for 2d drawings. I did not realize 3d was also available. This is great.