Computer Graphics World

thing he'd have to judge. "e first drawing I did had Glago with a typical alien that had tentacles and a bunch of eyes," he recalls. "But I tried to come up with something more interesting than that. I pared things away until I was down to a minimal form." Many of those minimal forms, an orb, became the aliens now in the film. "I hadn't seen aliens look like that before," Williams says. "Also, because they're simple, blank, and faceless, Glago can project onto them intentions that might not be true." e aliens became the second motiva- tion for creating the film in CG. "One of the great things about CG is that it al- lows many creatures on screen moving in sync," Williams says. "We could give them a strangely unnerving quality that creates an interesting impression on the audience. at's something we couldn't pull off in 2D, and maybe not even in live action." Darin Hollings, who came to Disney Feature Animation by way of the visual effects studio DreamQuest Images and Disney's e Secret Lab, supervised "Gla- go's" visual effects. At Pixar, short films are often a springboard for talent and a testing ground for technical innovation, and Ed Catmull, Pixar's founder and now presi- dent of Pixar and Disney Animation, car- ried that tradition to Disney. "Ed Catmull and Andrew Millstein [ex- ecutive vice president and general manager of Disney Animation] wanted us to try in- novative things with the short," Hollings says. "So, we created a new pipeline from scratch. We wrote new tools to manage all the assets, and a new lighting package to send everything to [Pixar's] RenderMan. Our goal was to get the highest quality level with the least amount of artist time as we could. We wanted to make things fast throughout the pipeline so when animators opened a scene, they could scrub the anima- tion. ey didn't have to do a playback." Pushing Pipeline Speed Although the crew based the pipeline on Autodesk's Maya, they designed it to be independent. "All the metadata, the way we put shots together, and the way we lit shots was independent," Hollings says. "e geometry stood on its own, and you could light a scene without opening Maya. Because the metadata holds the scenes to- gether, the pipeline is agnostic. However, everything comes back to Maya." Yun-Chen Sung, who had worked on a lighting package for DreamWorks' Shark Tale, created new lighting tools called Lilo for "Glago." Using Lilo, the artists would position lights in Maya, but they would adjust values, assign materials, and launch renders from Lilo. "Its base function is to create and manage the render passes," ex- plains Hollings. Lighters used such standard techniques as subsurface scattering, ambient occlusion, and so forth for Glago, the aliens, and the snowy world. "Chris wanted big expanses of emptiness, with sky, snow, and a dark figure, especially in the first part, photoreal in a contrasty way," Hollings says. "But, when you get close, he wanted lots of de- tail and lushness." With the streamlined pipeline in mind, Sung made sure Lilo could produce quick renders. "We didn't use AOVs," Hollings says, referring to RenderMan's arbitrary output variables, used to separate images by such attributes as diffuse, specular, re- flections, ambient, and shadows. While that provides control over individual layers, this multipass technique creates extra steps in the production pipeline. "We created efficient RIB files and did Glago on one level, the spaceship on an- other level, and so forth," Hollings explains. "We did old-school levels in compositing. It made it really fast to work on a shot. Toward the end of production, I could check out a shot, change the lighting, composite it, and put it in the queue in a couple of minutes." Helping make that possible was the crew's attention to speed throughout the process by creating lightweight models, textures, and rigs. "We had one super-light rig for the animators that didn't show every deformation, and then a second rig with all the deformations that animators could choose to use or not use," Hollings says. For facial animation, senior modeler Hi- roki Itokazu created a rig based on blend- shapes. "We wanted the animation of Glago to be subtle and different from ani- mation done in the past, so it was impor- tant to make sure the facial controls could convey that," Hollings says. "We thought about going with a next-generation defor- mation slider approach, but Hiroki had already set up a series of shapes and a user interface, and had the whole thing working without even being asked." Disney's proprietary XGen software grew hair inside tufts modeled with geometry to create the art-directed look of Glago's beard. February 2009 19 CG Short Films n n n n

• Cover