Computer Graphics World

JUNE 2010

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By GERGELY VASS Animation from models, landscapes, or other references. It is not any different for animators: One has to understand and completely embrace human or animal motion to be able to create expressive, stylistic, or realistic-look- ing animations. To study the mechanics of a talking face, only a mirror is needed; a galloping horse or a running cheetah, however, is a more complicated Early Motion-capture Techniques T o master the skill of creating imaginary characters or natural scenes—regardless of artistic style—painters, sculptors, and graph- ic artists spend a great deal of time replicating reality by working ever, a lot of old paintings showed running horses with all four legs stretched out, a pose that never occurs during any type of gait. Interest- ingly, horses and dogs in the shape of toys, sculptures, book illustra- tions, and stuffed animals are often depicted incorrectly. In 1872, Leland Stanford, governor of California, businessman, and race-horse owner, set off to find the answer for the popularly-debated question of the time: Did all four hooves of a horse leave the ground at the same time during a gallop? Supporters of one side believed that one leg has to provide support at any moment during the gait, but Stanford subject. Stepping through video sequences or 3D motion-captured data could be essential for learn- ing such complex motion—without good refer- ences, the subtle nuances of the movement are impossible to identify. But where should we look for quality references? Tere are some fine albums published more than 100 years ago that you should check out first! Te demand to capture animal and human motion emerged way before computers or even animation and motion pictures were born. Artists, doctors, and scientists were desperate to find out how different animals move, how birds and insects fly, or how cats manage to always land on their feet. One problem of particular interest was the locomo- tion of four-legged animals. As later research has proved, all four-legged animals have the same walking pattern for maximum stability. How- A former Maya TD and instructor, Gergely Vass eventually moved to the Image Science Team of Autodesk Media and Entertainment. Currently he is developing advanced postproduction tools for Colorfront in Hungary, one of Europe’s lead- ing DI and post facilities. Vass can be reached at gergely@colorfront.com. 8 June 2010 Left: The famous photographic sequence by Eadweard Muybridge, “The Horse in Motion” (1878). Right: An incorrect depiction of horse gaits on the painting “Le derby d’Epsom” by Théodore Géricault (1821). (and others) claimed the contrary, and wanted scientific evidence to back his belief. He commissioned the English photographer Eadweard Muybridge to develop some technique to capture the moment. Since motion-picture cameras did not exist at that time, Muybridge assem- bled a device with a special electrical trigger mechanism and custom chemical formulas for processing, and managed to photograph Occi- dent, Stanford’s race horse, completely airborne in 1877. (Tis can be seen in the famous 1878 photographic sequence by Eadweard Muy- bridge called “Te Horse in Motion.”) Expanding the experiment—still funded by Stanford—Muybridge devised a new (and, arguably, the very first) motion-photography, or chronophotography, scheme involving 24 high-speed cameras posi- tioned side by side and covering 20 feet of a long shed. Using innova- tive ideas to release the shutters as the horse (or other subjects) passed in front of the cameras, or alternatively by a clockwork mechanism, he cre- ated photographic sequences of a wide variety of animals and athletes in motion. Te images were not of particularly good quality, but the wood engravings based on them were successfully published in scien- tific and photographic journals. Muybridge ultimately produced more than 100,000 sequence photographs, of which approximately 20,000 were reproduced as collotype prints, and the reader is likely to find mul-

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