Assuming that you have a VEX-provided STEP file for a part, generating a LDraw/SnapCAD-compatible part file is doable. I described a procedure for doing that in this post (expand the details section):
Assuming that you have a VEX-provided STEP file for a part, generating a LDraw/SnapCAD-compatible part file is doable. I described a procedure for doing that in this post (expand the details section):