This post is for CAD Managers for Plant 3D! I found a great decompiler for Python the other day. It is called Easy Python Decompiler and i found it on SourceForge. If you want to get into the Variants.ZIP file and see how all of these 3D solids in Plant are created and attempt to create your own, try it out!
You can download it here: https://sourceforge.net/projects/easypythondecompiler/files/bin/