I will go through using free cad to model parts for any one interested, i am thinking I will demo it initially and then you can try and model something.
If you want to take part i recommend you find some simple parts to model, and install freecad 016 or 0.17 (they are only slightly different, and are available on all platforms for free).
If not we could try and model some of the parts from the robot.
Install instructions below.
https://www.freecadweb.org/wiki/Installingif your on ubuntu 0.16 is in your software list or there is a ppa for 0.17.
freecad can do all sorts of things like architecture, PCB and other things but i will focus on designing parts for printing or cutting.