Import from CAD System Which experiences and hints do you have when it comes to importing data from CAD systems like Siemens NX, SolidWorks, SolidEdge and so forth? 

I'm struggeling with this topic for one week now and just found the suitable solution of STL files. This comes with the downside of having tons of triangles where one single face would be sufficient, a huge file size and overall only flat surfaces which looks ugly with round objects e.g. tires. 

I just found out after trying a lot of combinations and options today, that NX has a well usable DXF export when it comes to curves and faces. They are even importable to blender as connected real splines. I was kind of astonished.
The downside is...exporting the volume body itself was not not of that charme. The body is made of flat faces and the resolution value is not respected. Whatever one inputs the resolution of the volume body remains constant.

VRML export has a usable resolution/tolerance value input option that works out fine. The wrl file gets imported in blender nicely. Downside: every connected face (all faces are flat) is an extra object. Joining the objects together is necessary. I also experimented with the wrl file in MeshLab and exported it from there to Collada, PLY and CTM files. The compression with CTM worked really well and didn't loose any visable faces or vertices. Also loading went like a charm. Faces as single objects issue remains, though.
The best solution I have found is .FBX.  Tried a lot of others including OBJ but settled on this.

In my case, SolidWorks files opened in Rhino, saved as .FBX, import that into Blender.

There are lots of export options when saving to .FBX in Rhino, had to set Maximum Angle to 2.0 (instead of 1.0) in order to get the rounded surfaces to appear round, and not jagged.