Breathing (the movement of chest and face features): I'd like to ask if it is hard to model and whether it is computationaly expensive. I recently noticed the great effect it has in Madagascar 3 movie, but (please, correct me if I am wrong) don't remember seeing it in any games (except maybe steam cloud in cold/winter setting) and very few animated movies does that to noticable degree (e.g. when it is necessary by the plot or situation).

I'd greatly appreciate answers from both movie graphics and game graphics perspective.