There is a good discussion of the issue here: Import Solidworks 2015 files and several other threads if you search for “Solidworks”.
In sum, current versions of SW do not import into current Rhino5 and development efforts from Solidworks for this ability have been (are?) stalled or unknown?
In the meantime, I’m importing STEP files from my Solidworks-using engineer with good success regarding model integrity. However, this is far from ideal since:
A) everything comes in as one layer and
B) all blocks need to be exploded in order for me to edit anything.
This process is very time-consuming for iterative design changes (and files sizes increase by a factor of at least 5).
Ultimately, ideal behavior in Rhino would provide layers and block behavior for SW files. In a perfect world (to dream, right?!?) various assembly components from SW would be a 1st level layer, with the individual geometry for these components being sublayers. This would permit much MUCH simpler viewing of desired components and editing.
Thanks for looking into this and good luck!
~Dave