Justin...what i worked on was collision detection..which was used for the entire animation. Think of it like this...imagine there being these invisible "cards" around the character (shaped similar to a pringles potatoe chip*..whenever 2 of these get close to each other.they press against the mesh and cause it to "collide" realistically so that 2 characters dont go thru each other..
the image above is showing how it worked with all characters at once..but it was used for the entire thing..