FreeCAD - An open-source parametric 3D modeler
MATLAB - A high-level language and interactive environment for numerical computation, visualization, and programming
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
Wolfram Mathematica - Mathematica has characterized the cutting edge in specialized processing—and gave the chief calculation environment to a large number of pioneers, instructors, understudies, and others around the globe.
SketchUp - 3D for Everyone
COMSOL Multiphysics - COMSOL is the developer of COMSOL Multiphysics software, an interactive environment for modeling and simulating scientific and engineering problems.