 Peter Gabriel's latest MTV video hit, Steam, is sexual, intellectual, and metaphysical. Director Stephen Johnson, best known for creating and directing Gabriel's Sledgehammer video, has developed a "visual shotgun, a rocket sled to heaven and hell" packed with computer-graphics effects, accordine to Colossal Pictures  (San Francisco), who produced the video in association with London-based Real World Productions. "This video was definitely conceived with computer graphics in mind," says Brad deGraf, the computer animation director at Colossal.
    A large part of the video was created using deGraf's own performance-animation software in combination with a motion-capture system develo~ed bv Umberto Lazzari
 and Francesco Chiarini of Superfluo (Los Angeles). With this setup, the movements of live dancers are used to drive the computer animation. In one scene, in a computer-generated Eden complete with dancing vegetation, the bodies of Gabriel and his female companion are transformed into doll-like characters, with Gabriel's head on one of the dolls and the woman's on the other. These "dolls" are actually digitized models of human bodies that are completely driven by the actors' motions. DeGraf explains that the dancers wear retro-reflective dots on their joints. Infrared light, emanating from four cameras, is reflected off the dots and tracked hv a  computer to produce the 3D coordinates of the joints over time.
    This system is used in another scene where fire and ice come together to make steam. In this case, two female dancers drive the fire (created with  particle software) and Gabriel provides the motion for the ice. The video also features dancing Metaball blood (Metaballs are a relatively new computer graphics primitive) and a Cyberwaredigitized, fully animated version of Gabriel's head that is practically indistinguishable from reality.
    Almost as im~ressive as the computer graphics in the video are the logistics behind its creation. "It was kind of a liveaction paradigm," says deGraf In fact, the project began just one week after deGraf signed on with Colossal to start the company's computer animation group. "Essentially, we didn't have any computer animation capabilitv here at that time. We basically ramped up the group to do the project in two days. We did everythin~ in five weeks. which is a ridiculous amount of time to do what we did." About one-quarter of the computer animation, including the fire and ice dancers, was co-produced by Homer & Associates (Los Angeles). The group hired a number of freelancers, rented four Silicon Graphics workstations, and relied heavily on Softlmage and Wavefront software.
    According to deGraf, Gabriel and the professional dancers adapted to the technology quickly: All the motion capture was completed in two days. Many of Gabriel's scenes were shot in front of a blue screen, which meant that he had to imagine situations and respond to them in a field of blue. And the technology involved performed beautifully as well. "I was really amazed," says deGraf. "Consid-
 er that we started out with no crew and no equipment and that we had to deliver at 25 frames per second on PAL to London. And we only had the director for one day in the middle of the production. But it all went like clockwork." Every shot has from six to 37 levels of layered imagery.
Although he was pressed for time on this project, deGraf is pleased with the outcome. "One of the things that was so enjoyable about this project is that we asked, 'What can we do in one day,' and we did it. Maybe we could have fiddled with something a little more, but [the difference] wouldn't have been that noticeable."
    To date, the motion-capture and performance-animation techniques have been used mostly to produce 30-second commercials. Such work  alone, says deGraf, is not sufficient to further the technology. Although there is no longer a resistance to using these techniques in videos such as Steam, deGraf believes that there is still a lack of understanding of their capabilities. However, with the success of its first computer animation project under its belt, Colossal already has a number of other productions in development, including some feature-film work, that promise
to create more steam.   CGW
