Fully Support Exporting As CSG

[EmperorArthur]

The CSG file format is a subset of full OpenSCAD file format. As a rough approximation, it can be considered analogous to a STEP file in that it does not contain meshes, but rather object primitives.

Advantages

• Mesh operations are tricky, and can be complex.
• CSG files should be reproducible, making testing the final output possible.
• Tools like FreeCAD primarily use CSG to interact with OpenSCAD, and need to use hacks for everything which cannot be converted to a CSG

Limitations

As CSG only allows object primitives, mesh operations are not allowed.

From the FreeCAD CSG Page:

• projection
• surface
• render (ignored)
• cgal operations: minkowski, glide, path, subdiv, hull

We currently use some of those gcal operations in our code. Specifically, minkowski.