SketchUp - 3D for Everyone
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.
GNU Octave - GNU Octave is a programming language for scientific computing.
DraftSight - Discover Dassault Systèmes®' DRAFTSIGHT™ Professional CAD software that lets you create, edit, view and markup any kind of 2D drawing. Learn more here.
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.