I am interested to know if it is possible to create a plugin /extension/add-on/ add-in to import designs from Free, Libre, and Open Source CAD Software such as FreeCAD and SolveSpace into SolidWorks. Given that the file format of those software is openly available, one should be able to write plugins for other software (i.e., SolidWorks) to import them. However, I can't find a simple tutorial, or any documentation for that matter, explaining the basics of creating plugins for SW. I guess it has to do with Visual Basic API. I would appreciate it if you could:

1. Point me towards simple instructions or even a tutorial on how an import extension could be made.
2. Tell me about the feasibility of creating a plugin to import from FreeCAD, and SolveSapce
3. inform me about the feasibility of parsing code based CAD software such as OpenSCAD and other programmatic CAD software.

P.S. I am aware of open standards such as STEP (step/stp Standard for the Exchange of Product model data) and IGES (iges/igs Initial Graphics Exchange Specification) but I'm obviously not interested in using those for transferring design across different software.