Blender - Blender is the open source, cross platform suite of tools for 3D creation.
FreeCAD - An open-source parametric 3D modeler
Onshape - Onshape is the first full-cloud 3D CAD system. It runs in a web browser and on any mobile device.
MATLAB - A high-level language and interactive environment for numerical computation, visualization, and programming
MatterControl - MatterControl is a free, open source app that lets you organize and manage your 3D prints.
Inventor - Inventor is a 3D CAD software that lets you quickly create 3D models with embedded intelligence, intuitive workflows, and optimized performance.