I am currently in a project where a lot of 3D printing designs need to be done. They are all parameterized, so I'd like to write Python code to generate those design files (in .STL format) for me.
Is there a Python package that can do this? Because currently I am all doing those by hand using SolidWorks.
Yes there is... It's called FreeCAD.
The assembly module is already in the devel version (as of 06/15/2014) and will be of production quality really soon for real assemblies!