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VFX Pro Feature Incredible Animation: Pixar's New Technologies
The supervising technical director is responsible for setting up that pipeline and the accompanying departmental structure, and deciding in what ways the company's proprietary software and procedures will be pushed--or identifying any third-party software that will be required to do the job. "Then, once the show is up and running, I ride shotgun with the director, helping him negotiate the production process." Computer-animated feature films go through the same four stages as animated and live-action films: development, pre-production, production and post. In the development phase, storyboards are drawn based on a text treatment of the film to serve as the blueprint for the action and dialogue. For "The Incredibles," Pixar story artists then created 'story reels' to depict writer/director Brad Bird's script. It was in these reels that the timing of sequences was first addressed and fine-tuned. "In a typical animated film, the storyboard is only about the story. It's like an illustrated script," explains Sayre. "It shows the emotional interaction between characters, but there's very little to do with camera, camera moves or composition. Brad's storyboards, or story reels, are essentially like an animatic. They're very specific, with 3D camera moves and the beginnings of effects." Story reels for "The Incredibles" were created using a new combination of technology for Pixar. Working in Adobe Photoshop, story artists drew scenes on Wacom Technology Cintiq LCD tablets instead of drawing on paper and then scanning those drawings for manipulation in the computer.
The Character Team After the storyboards and reels are completed, the animation process begins, though not before a few preparatory steps are accomplished. The characters to be animated must first be created in the digital world. This process, which entails character sculpting, rigging and shading, is handled by a character team comprised of technical directors and artists. Basic character design is first worked out via physically sculpting a maquette figure of each character based on illustrations from the art department. While for past feature projects, such as "Monsters, Inc." and "Finding Nemo," Pixar artists would have scanned the maquette into the computer using a touch digitizer (accomplished by drawing a grid onto the figure and identifying each grid point in 3D space using a pen-like digitizing instrument), a different process was applied for "The Incredibles." "This time we did it entirely without digitizing," says Sayre. "We had a small team -- two people -- of digital sculptors. They literally just looked at the maquettes, talked to the head animators, the director and character designers, and sculpted directly into the machine." They used Maya software. "We've always had the opinion that 3D scanning is valuable if you're trying to match something directly, like tracing. But there are plenty of artists who don't need that step. A really good artist can just draw."
"This film was a big departure for us because it's all about humans, as opposed to animals or toys," said Sayre. "We had to almost completely overhaul the character rigging process to come up with a system that was more anatomically based, with bones, muscles and skin. You want the audience to feel like the characters are, say, being put in jeopardy, and the subtleties of how skin and bones move relative to each other help accomplish that." Not to say there's no hint of cartooniness. "Nobody's going to mistake them for real humans. They don't look like anybody you've ever seen." Once the characters are modeled and rigged, they were shaded. Shading defines the way the surface of an object or character responds to light, both in terms of color and texture. "A good analogy is the difference between human skin and plastic," Sayre explained. "They have might the same color, but the human skin is going to have light scattering around inside it, whereas plastic will have light bouncing directly off of it." Clothing and Hair While the digital sculpting, rigging and shading of characters was handled by the character team, another group of artists focused on modeling the characters' clothing and hair. "We actually had to tailor the clothing," noted Sayre. "The difference between an ill-fitting suit and a well-fitting suit is how it's tailored. It's quite a challenge when you have a character who, earlier in the film, is a trim Mr. Incredible, and then later, he's an aging superhero with a big gut." Pixar clothing simulation artists first visualized the wardrobe items using off-the-shelf commercial tailoring/patterning software, then brought these models into Maya for pixel manipulation using the company's proprietary plug-in suite. The wardrobe models then moved into Pixar's simulation software. Animators are not required not have the clothing design completed before they begin their character work, unless the character is to have several costume changes. "Even in that case, you don't actually need to have the costumes completely figured out before you begin animating," explained Sayre. "But from a production flow, there are a lot of incentives to having the basics of what clothes the characters are going to be wearing buttoned down before you get into production. For a character such as the intriguing Mirage, for instance, you'll need to know if she's wearing a dress or a pant suit in a shot because it affects the way she's going to be able to walk." The final prep step is layout, the animation equivalent of blocking a shot. The layout crew choreographs the characters and uses a virtual camera to create shots that capture the emotion and story point of each scene. Layout often produces multiple versions of shots to provide the editorial department with choices for cutting the scene for maximum storytelling effect. "The layout artists break down how long each shot will take, working closely with the editorial department," Sayre said. "They determine basic things like where the camera will be in a shot, if and how it will move, what characters are in the shot, and, if so, how they will move, very broadly, relative to each other."
Once layout is complete and the scene has been cut, the final version is released to animation. These artists animate the characters by making use of the work of their predecessors in the production chain. "The animators don't have to deal with all of the chewing gum and bailing wire details that the technical directors do. They're able to see the characters in a much higher-level interface. Their interface is more on the level of, 'Here are the characters, and here are some controls that I can grab and manipulate,'" explained Sayre. "It's quite an achievement that we've gotten it so that we're doing skin and muscle and bone with high-level controls they can actually see. They don't have to just work in skeletons or cut-ups. The skin will be in the same place it will be when we render it out at film quality." One of the systems responsible for providing the animators such control is the arrangement of Pixar's computer processing and storage systems into a Model Farm, Image Farm and Render Farm. The Model Farm, a collection of Network Appliance FAS960 filers, contains all of the intellectual property -- created in the steps described prior to animation -- to generate the components that make up each frame or object. Pixar artists have called this collection of modeling data a 'digital backlot.' The Image Farm is a pool of storage containing the completed image frames. A third area, the Render Farm, actually generates those completed frames, pulling together the information from the Model Farm in a process referred to as rendering. The Render Farm consists of 1,024 Intel Xeon processors inside eight RackSaver BladeRack supercomputing clusters running Pixar's RenderMan software. The Render Farm features two terabytes of memory and 60 terabytes of disk space. "The Render Farm is a room full of about 2400 CPUs that just crunch away," said Sayre. The artists require almost 0.25 million NFS operations a second -- a number that would destroy the CPUs if precautions weren't taken. To ensure their supercomputing clusters aren't overloaded by sheer number of operations requested of them, DNFS caches sit between the Render Farm and the Model Farm filers. Accessing a volume of 3D imagery via DNFS cache reduces the amount of traffic to the server, allows artists faster access to the imagery and, therefore, decreases render times. During animation, the digital artists access the intellectual property (the characters' shading, textures, etc.) using a collection of proprietary dynamic shared objects (DSO) in combination with the RenderMan shading language. The data is compiled quickly, allowing the textures to be represented without having to utilize the resources that would be required during complete rendering. This process allows the animators to get a sense of how the characters will appear when finally rendered while still allowing them to manipulate characters easily during the animation stage. After character animation is finished, several other steps take place to complete the scenes. "You have to remember, in animation, everything is production designed," Sayre said. "If there's a can of soda in the scene, an artist has to design it. They're actually modeled and then shaded so that they can be set-dressed and the final set can be built."
The effort actually follows in the steps of classic cel animation, which also employed the work of effects animators. "We actually had one artist who had previously drawn completely hand-animated 2D effects for the former Sullivan/Bluth Studios, for both live-action and animated feature films," Sayre said. "He was so well versed in effects animation that he was sculpting lightning bolts in 3D in the computer. It was amazing." The Directors of Photography Computer animation also utilizes the talents of another artist, who works under a title common to live-action film work: director of photography. "The Incredibles" actually had three DPs: Janet Lucroy, who concentrated on lighting, Andy Jimenez, who concentrated on camera, and Patrick Lin, who focused on the layout and composition aspect of the camera. The animation DP's background must be a varied one. "Janet, for instance, actually has a painting, fine art background, as well as a CG background," explained Sayre. "Because these films are so heavily art directed, heaving a strong art background is crucial."
Animation is reviewed in a process that, again, borrows from the classic animation period. The director and supervising animators view work in progress through occasional walk-throughs, visiting individual artists' workstations. Animation sequences are viewed in dailies to ascertain the current state of a scene or sequence. The team views footage on a color-calibrated CRT monitor as well as with widescreen projection to assure the accuracy of color decisions.
Film dailies are also screened, though not to the extent they were for previous projects. "Previous to 'Finding Nemo,' film dailies were an important part of the process, but now they're really just something for me and the DP," said Sayre. "The DP is concerned with color contrast and creative issues, while I'm mostly concerned with making sure everything looks as good as it possibly can on film. All of the finals and approvals come from watching sequences digitally projected in our main theater." While the computer animation field still draws on the process of its cel animation heritage, it now has many of its own disciplines, and specialists are required for things never imagined in those days. "I'm sort of an old-timer," Sayre said. "Back when I started, there wasn't coursework in computer animation or anything like that. It's been really fascinating to see this industry evolve." © Copyright 2003 by United Entertainment Media, Inc. |
