Computer Graphics World

November 2008 24 n n n n CG Animation of layers for each material in Bolt. "When we rendered the materials, we could decide whether we wanted a looser, abstract interpretation, or more detailed look," Lusinsky says. Sometimes, the artists made the decisions arbitrarily; other times, they set up the system to make procedural decisions based on depth cues for example, to render less detail when a material is some distance away from the camera, or, similar- ly, to render looser details in shadows. Lastly, to create painterly shadows, the technical team developed new technology that works within RenderMan to fringe the shadow edges. "We developed tools and techniques that give the edges a different color than the interior," Lusinsky notes. To do that, the shaders referenced libraries of painted brushstrokes. For the deep shadows in the characters' hair, though, the crew leveraged the capa- bilities of technology already within XGen. "XGen keeps track of where each groom (guide) hair grows, how many hairs are as- sociated with it, how far away it is from the camera, how big, and so forth," Lusinsky says. "Because it is open-ended and anyone can write expressions or plug any kind of code into it, we used XGen to shade the hair in a more art-directable way. Rather than being dependent on volumetric shad- ers, we derived volumes of hair using in- formation from XGen, which helped speed up hair renders quite a bit." Believable Light For cinematography, Felix turned away from animated films and toward live-ac- tion movies of the early '70s. In particular, he liked Vilmos Zsigmond's cinematog- raphy in Heaven's Gate and the "soft sen- sibility of light" in Ridley Scott's McCabe & Mrs. Miller. Scott's photography in the "traveling picture" elma & Louise also inspired him. On the technical side, Lusinsky's team studied film stocks, particularly older ones. "We developed film curves that all the ren- ders used on our show," he says. "at gave us a painterly textural world that seems pho- tographic because the light is photographic." One film stock provided the color curves and contrast range for the sequences in which Bolt stars in the TV show; the other provided correct exposures for the rest of the movie, when Bolt rumbles through the real world. To accurately light Bolt's jour- ney across the country, Lusinsky and others traveled his route themselves. "We wanted to have a naturalistic feel for the lighting, so we spent a lot of time studying light across the country," Lusin- sky says. "We wanted to capture the qual- ity of the light in each area and pull color palettes from each area." To light shots in the garment district of New York City, for example, they developed a desaturated color palette that mimicked humid afternoons when the sun is soft and muted. In Ohio, they discovered that the humidity in the air tended to cast the sky a turquoise color. For Los Angeles, they ren- dered the sun hot and hard. "We really tried to capture the subtleties that make each place different," Lusinsky says. "e light, the architecture, the foli- age. We wanted to be true to the locations so you felt like Bolt was in the real world. We thought if we made it too stylized, peo- ple wouldn't believe he's in a real world; it would feel like fantasy. We wanted it to be believable. And, John Lasseter is really big on details in the environments." When Lasseter and Catmull arrived at Disney Animation, they tore down walls, literally and figuratively. Formerly walled- off offices became an open conversation pit with a jukebox, magazines, and a cereal bar. Layers of management peeled away, too, which invigorated the studio with new, creative energy. "Before John [Lasseter] and Ed [Cat- mull] arrived, I kept saying how great it would be if we had a boss like John," Howard says. "He's like a big kid who loves animation, and that enthusiasm fil- ters through the crew." Williams adds, "John brought so much energy and excitement. He raised the qual- ity bar. He gave us a real creative surge." Bolt was the first lightning rod for that renewed energy, and it could hardly be more fitting. In the film, the star learns that he doesn't have superpowers. In making the film, the animation studio remembers it does. n Barbara Robertson is an award-winning writer and a contributing editor for Computer Graphics World. She can be reached at BarbaraRR@comcast.net. Animators gave Bolt cartoony superpowers when the dog starred in his TV show. When Bolt travels through the real world, though, the animators followed John Lasseter's maxim of "truth to materials," and made sure the little dog behaved as a real dog would.

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