This project is soooo exciting !
Mecha was sleeping for a long time before I stumbled upon this article, Advanced Character Physics, and decided to implement it (in Ruby of course).
Wow, now I have not been sleeping for 3 days, hacking my little game. This article changed my vision on doing physic simulation in 3D. I have implemented motors, controls over strings with keyboard, and designed a nice little excavator arm with hydraulic cylinders that you will find in the examples.txt file!