I was wondering if anyone has any idea how I can go about getting a .3dm file to Substance Painter with-out converting the file to another format. Preferably a bridge where in Rhino, I would use mesh to nurb, then create a new UV and then call up Substance Painter to add the texture, add it to the nurb then use all the functions in Rhino to unroll/flatten the object with the texture intact! As all know…a textured mesh when converted to nurb destroys the UV data, and converting the file to another format does not allow me to use the unroll/flattening capabilities of Rhino. Before anyone suggest it…I understand I can save the file to an object, then texture in Substance then flatten in Pepakura, but it’s capabilities are EXTREMELY lacking compared to RHINO…and then Rhino becomes nothing more than an expensive file converter, and I could just as easily use a free converter or Blender and have saved hundreds of bucks…
Hi Scott - sorry, I have no idea how to help here. Sounds like you need to pester the Substance developers to support the 3dm format.
-Pascal
Yep Thanks…I did that… I saw my request for needed additions shuffled off to user support instead of add ons…so I can guess it actually went in that round metal can next to the desk. 
Hi Scott - in case it helps the pestering, you can point them here:
http://4.rhino3d.com/5/rhinocppsdk/index.html
-Pascal
Thanks…I was looking at that. and wondering about it…but being so new to Rhino I soon got so lost I gave up for the time being…seems plausible to create a bridge if one had a clue what they were doing!
The so called bridge from a .3dm file to 3ds max does nothing more than convert a .3dm file to .fbx and that you have to load into 3ds max manually, same with the Substance bridge to 3ds max, they are not bridges but file converters. Autocad will read and import directly a .3dm file but even software in house at Autodesk does not play well together and getting from autocad to 3ds max you are stuck again…they really don’t want anything transferring back and forth…I used to use Poser and Bryce and the bridge there was great…great back and forth between the programs!
You can use this LIVE connection, not for Rhino, but who knows:
You can contact the developer using Discord: https://discord.gg/BTpZq5d