Animation modelling with physics

This is an old video: Marisa, Reimu and Sakuya from Touhou dancing to Michael Jackson's Smooth Criminal.

This is a newer one. A bunch of silhouettes in a remix/rearrangement of a Touhou song.

I believe both have been done by using some 3D modelling program that can use physics models to model how the hair etc go.

I'm very impressed with the latter one. No clipping - for obvious reasons and it looks great. Now if I only cared about that piece of music...