Universal Gcode Sender - A full featured gcode platform used for interfacing with advanced CNC controllers like GRBL and TinyG.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
bCNC - Development
FreeCAD - An open-source parametric 3D modeler
Candle - GRBL controller application with G-Code visualizer written in Qt
MATLAB - A high-level language and interactive environment for numerical computation, visualization, and programming