Based upon Google search:

The Siemens Jupiter Tessellation specification is available.
The format can contain both polygon and brep information, +...
There is a $199 Rhino importer.
There is a $60 Sketchup importer.
Can be opened in Fusion 360.
I have never seen a JT file.

How enormous would a NURBS file translation be?

- Brian

ASPOSE link saved for the future!

https://en.wikipedia.org/wiki/JT_(visualization_format)