SolidWorks mesher really isn't designed for rendering. It produces spikey triangles that screw up smoothing normals. Additionally, it seems to hang when creating files with more than 7 million triangles. I don't know if this has improved in SW2018.
The best option for generating meshes for rendering is via Moi3d. It does not import a native SolidWorks file, so you would save as STP.
Hello Matthew,.. there are two ways within SW,... if you have Visualize (using SW Pro),.. you can export it as FBX.
Or.. buying a FBX addin from SimLabs (it worked pretty good and was inexpensive)
I personally have Rhino3D (open sldprt/sldasm) and export FBX...
Alternatively, Chris' suggestion for Moi3d is spot on!.. using SW polygon exports are not very good... and Moi3D is a very nice/simple/inexpensive and known to be a very good with poly outputs!