Biped ragdoll movement with physics or animations?

Hello!

I’m trying to understand how ragdoll movement works because in there aren’t a lot of tutorials or info in internet and I have questions for work with it.

First, if you can guide me to work with this physics thread… thanks a lot.

Secondly, I saw videos about biped movement and some of them have a cube or something like that near. Is the movement of this cube the basic of ragdoll movement or animations? How it works?

Thanks a lot!
Álvaro.

Up, can somebody help me?