GNU Octave - GNU Octave is a programming language for scientific computing.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
MATLAB - A high-level language and interactive environment for numerical computation, visualization, and programming
FreeCAD - An open-source parametric 3D modeler
Xoctave - The Affordable Matlab alternative which makes you save money. Xoctave is a powerful software that is meant to unleash the power of GNU Octave by creating a complete scientific computing environment.
SMath Studio - Tiny, powerful, free mathematical program with WYSIWYG editor and complete units of measurements support.