Free and open source pattern design software
LibrePLM integrates CAD editors in Odoo / LibrERP
Python script for calculation of deflection of elastic ropes.
Software for electromagnetic simulation
Python tool for section property evaluation and stress calculation
OpenNum lets you distribute solvers with a nice graphical interface
An Open source Analysis and SImulation Toolbox for Fuel Cells
CNC control software
dedalo is a 2d cad drawing software written in python3.