I struggle with this topic since forever, I hope this time you’re close to solve this problem and leave it in the past.
I can’t export correctly UV unwrapped Breps with Edge Softening.
I can’t rely on extracting render meshes out of geometries and exporting them because every change means new meshes and losing the connection between UE4 and Rhino objects.
RH 7 Datasmith mapping soft edges.3dm (2.1 MB)
Please take a look at mapping - on the right side it looks how it should
These are the same meshes, but the left one has wrong UV mapping
Rhino 7: Everything looks fine