How do we move when we breathe?

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How does your body move when you breathe? Well, of course the rib cage expands and contracts, but surprisingly the movement is more up and down than it is in and out, says Michael Black, co-author of a computer graphics study presented at the recent Siggraph.

There are many more small but observable movements going on. The arms push out, the head goes back and forth, and the spine flexes. The movements are slightly different for "stomach breathing" compared to "chest breathing," something that singers are very conscious of. One possible flaw in the methodology of this study is that subjects were asked to "breathe normally," a sure way to make them breathe unnaturally.

Once you learn to recognize the subtle body changes that accompany breathing, you won't look at a posed model the same way, and you'll notice actors in movies controlling their breathing as part of their performance.

Animators will be able to input this breathing data with simple controls, including a spirometer, which records breathing volume. In the future, when actors record their voice parts for CG animated films, they'll be able to record their breath acting as well. That information will yield a more believable and lifelike performance, whether the character they're playing is a realistic human or a talking turnip.

The authors are: Tsoli, A., Mahmood, N. and Black, M.J.,
The paper is entitled: "Breathing Life into Shape: Capturing, Modeling and Animating 3D Human Breathing"