Google Sketchup

[Eric222]

I would definitely second everything everyone has said already. I have used Sketch Up just to play around with some house designs and other things, but if you need anything complex, Autodesk products are the way to go, especially since you can get them for free. Certain things such as the robot chains, belts, and electronics would be impossible in Sketch Up from my understanding. If the preloaded tutorials do not help your learning, try looking into getting some workbooks. That is how I learned at first.