Free and open source pattern design software
a parametric 3D CAD modeler
LibrePLM integrates CAD editors in Odoo / LibrERP
Open-Source Multiphysics FEA (FEM) Package
Demonstrates a quadtree for spatial indexing of triangles
An Open source Analysis and SImulation Toolbox for Fuel Cells
ALST is a CAD for all imaginable logic systems (binary, ternary, etc)