Video is in real-time
Maya c++ node based on hierarchical bundling algorithm, developed by Danny Holten and described here . Implementation of the algorithm was used by Manuel lima of visual-complexity to elegant effect here .

Curve straightening (see video) is lame attempt based on local weights only.Hence doesn't 'hold' original shape very well. Probably needs 'pinning'/anchoring of some cvs.duno.will fight that battle another day.yet another battle-for-another-day: spring based curve-relaxing.