We all use free open-source software to run our printers and design the things we print. Please remember to say “thank you” (or flattr / make a small donation) to the developers who dedicate their free time to these awesome projects.
My thanks go out to (including, but not limited to, in no particular order):
OpenSCAD: OpenSCAD - Community
Erik Zalm with the Marlin Firmware: GitHub - ErikZalm/Marlin: Reprap FW with look ahead. SDcard and LCD support. It works on Gen6, Ultimaker, RAMPS and Sanguinololu
Kliment with the Sprinter Firmware and Printrun: GitHub - kliment/Sprinter: Firmware for RepRap printers and similar devices , GitHub - kliment/Printrun: Pronterface, Pronsole, and Printcore - Pure Python 3d printing host software
@foosel with @OctoPrint : http://octoprint.org/
@Daid_Braam with Cura: GitHub - daid/Cura: 3D printer / slicing GUI built on top of the Uranium framework
@Alessandro_Ranellucc with Slic3r: http://slic3r.org/
@Roland_Littwin with the Repetier Host and matching Firmware: http://www.repetier.com/
@Mark_Moissette_ckaos with CoffeeSCAD: http://coffeescad.net/
Please let me know if i forgot someone!