How to import (proE) prt files into Rhino 5?

How to import (proE) prt files into Rhino 5?

You can’t.
The ProE prt file is a proprietary format.
There probably is a plug-in on the Resources page that will add support for that file type.
The other option is to get a STEP file from ProE.

Except for online services that charge a conversion fee, the plugins range in the hundreds, if not thousands of dollars.

That’s correct. The file reading function libraries are licensed from the application owners; in this case, ProE.
ProE want you to use their software to edit their files.
That’s what “Proprietary” means.

Rhino has a native file format too “3dm” but we make the tools for reading and writing them available for free.
It’s a business decision.
ProE made a different one.

Thank you John, I’ll need to find someone with PRO Engineer here and see if they’ll agree to convert these old prt files for me - I’m in China! Should be easy!

You can sign up for the free onshape account (the one that is limited to 10 private projects).
Onshape should be able to open ProE files (and ll the other mayor Cad file types for that matter).
Then You can export to STEP, IGES or Rhino file format.

Cheers, Norbert