Graphics3D from Mathematica to SolidWorks (for 3D-printing)

You need to use Normal to explicitly apply the various transformations, resulting in an ordinary collection of polygons which Export can translate to STL. Unfortunately, it looks like Normal has a problem when multiple transformations are supplied to GeometricTransformation. We need to handle this with a specific rule.

Assuming g is your Graphics3D:

gn = Normal[g /. GeometricTransformation[prims_, tf_List] :>
    (GeometricTransformation[prims, #] & /@ tf)]

Export["test.stl", gn]

This produces an output file. I do not have SolidWorks to tell if it's any good or not.