Can Rhino convert STEP files to .3dm?

As I export 3dm files I can convert them to STEP format. Can I reverse that process and import STEP files and convert them to 3DM ?

Ed Cooper

Yes. Just save as a rhino (.3dm) file.

Thank you Siemen. Why can’t I edit them once I have them in Rhino?

Are they edit protected like PDFs?

I am particularly interested in importing nuts and bolts to include in my designs.

Your advice is greatly appreciated


Hello - use ExplodeBlock on incoming step files if you see the warning about the objects being inserted as block instances.


Hello Pascal

Thank you for your advice.

I am still finding some problems with importing and editing both step files and STL files of threaded bolts into Rhino for Mac. I can get them into Rhino and can explode them but then cannot get the exploded components to accept editing procedures like wire cut, union or cap planar holes.

I am enclosing sample files. When the step file is imported and exploded, the thread of the bolt is no longer present. The STL comes over with the thread and can be exploded into its component parts but those parts will not allow the editing procedures to apply to them.

Your further advice will be gratefully received.

Ed Cooper

Screw-M5-20-20-6-8-25-Yes.stl (2.03 MB)

Screw-M5-20-20-6-8-25-Yes.stp (42.4 KB)

.STL files are meshes. It’s a different type of file and cannot be edited in the same way as Rhino’s NURBS (Poly-)surfaces.

Try using the step files. With those it is possible to use procedures like wirecut etc.

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Thanks Siemen but as you can see in your demo, the thread itself does not appear in Rhino when Step files are used. Do you know of a source of ready made 3dm files of screw threads? Alternatively are there any Rhino for Mac tutorials showing how precision threads can be made?

Thank you for your prompt response


If you want accurate threads that can be imported and edited check out
I download SolidWorks files and import them because they come in on a layer with the part # so I can then order them for the job later on.

Yes, you’re correct I didn’t read properly. I’m guessing they leave the thread out because it would highly increase your file size if you use a lot of those in your model.