freeCAD

I came across FreeCAD software in the context of sailboat design.
I don't know how useful or easy it is to learn, but I found some promising results online. 

https://forum.freecad.org/viewtopic.php?t=64136&start=10

Here is the download page for MacOS, Linux, and Windows.
https://www.freecad.org/downloads.php

From the FreeCAD page:

"While the FreeCAD core functionality is coded in C++ for robustness and performance, large parts of the external layers, workbenches, and almost all the communication between the core and the user interface is coded in Python, a flexible, user-friendly, easy-to-learn programming language. From Python code, you can do just anything in FreeCAD, from simple one-line commands in the integrated Python console to recording macros, coding your own tools up to full custom workbenches."