HeeksCNC is an open source, 3D CAD/CAM software mainly written by Dan Heeks, danheeks@gmail.com.
It uses wxWidgets for the graphical user interface, OpenCASCADE for the solid modelling, opencamlib for the surface machining, Boolean and Clipper for the polygon offsetting used in the pocketing operation ( via the libarea project ), glfont2 for the text in the graphics window, voxelcut for solid simulation
I am not charging for my ownership of the code as it is open source and not all mine. I am just charging for my work in making a tidy Windows installation, writing some online help, replying to emails from people who have bought it ( danheeks@gmail.com ), fixing bugs.

Get The Source Code:

You can build HeeksCNC yourself, but you will need software skills to do this.

The source code and instructions ( see wiki pages ) are here https://github.com/Heeks/heekscnc

Usage Documentation
For HeeksCNC, check http://heeks.net/help