A former gymnastics coach turned game developer delivers the technical knowhow behind delivering convincing character motion, in Gamasutra's latest feature,
Center of Mass: Tools and Techniques for Animating Natural Human Movement, taken from Game Developer magazine.
Eiko Oba works for Kung Fu Factory, which collaborated with THQ and Yuke's on
UFC Undisputed 2009 -- helping work on character animation for the popular mixed martial arts game. She also has a background as a gymnast and coach.
In the feature, Oba describes how finding a character's center of mass (or "COM") is essential to realistic character animtion. She writes:
Your balance and movements are always affected by gravity. As a gymnast I learned how to control and adjust my body's COM to perform various actions. Tumbling, balancing, and so forth, all require an adjustment of the COM. Some animators I know who are martial artists also understand this concept, so they can see how the COM flows and adjust the character's body appropriately. Adjustment of the COM is something we all do naturally in real life when performing actions like dancing, running, and so forth -- but it's not easy to create this in a fictional character.
Oba goes onto describe how the animation team uses Excel as a tool for properly simulate character animation:
The advantage of using Excel is that once the formula is set up properly, the calculation result is updated immediately when variables are updated. Excel can also export a visual representation of how the COM should move in the form of a graph. By doing this, COM translation and rotation is broken down into x, y, and z components, which can be used as a visual aid for reference.
Oba shares the equations necessary for this work, as well as tools -- and describes the tricky trouble that animators have gotten into when miscalculating the center of mass.
The full feature,
Center of Mass: Tools and Techniques for Animating Natural Human Movement, is live today on Gamasutra.
