I have seen someones make STEP ---> FreeCad (free) --> STL --> Blender (not personally tested)
they say that works fine...

.stl is a printing format. No colors, no uvs, you are even not supposed to store normals. (normals are recreated by the loader, based on the vertex order, and normalized ... so not for shading purpose, as it should result into a faceted "look").

So I guess the .stp loader is welcome :O).

It will be still a nightmare to manipulate I guess (like doing so uv's etc), dealing with nasty unselectable triangles etc ... you can't beat MoI mesher so easily :)

There an experimental build for windows that has the ability to import 3dm file into Blender Nubrs surface object but is at early stage and need some workaround after importing.. now file import can read rhino 6 or higher file.
This at early stage and need some tweaking of surfaces with end point U V. And for now don't supports all features, such as trimmed surfaces but works better after saving file and open that in standard build e changing the end point selecting sometime both end UV or one side end..
Below my test.












Link to Blenderartis topic.

https://blenderartists.org/t/branch-soc-2014-nurbs-update-to-master/1207889/6