Issue link: https://digital.copcomm.com/i/48986
n n n n Character Animation referenced the comic books for design and the real world for textures and dynamics. The film may trace its origin to comic books from the early 1940s, but this is not your father's ani- mated film. The attention to detail is amazing. "We ran this show exactly like every other show," says Simon Clutterbuck, digital crea- ture supervisor, "as if we were doing 100 shots in a visual effects movie. The focus on every texture, every motion, every simulation was intense. We never said, 'Oh, that's done,' and locked an asset. We looked at everything ev- ery day. We had a process where things ran in parallel; we even built while lighting. If some- thing in a shot needed to change, we changed it. All the way through production, shots con- stantly evolved and got better and better." for Hergé. But we had to develop a three- dimensional character." The artists started with the 2D character, picking frames that, when combined like a flip book, created a three-dimensional look. Next, they translated that look to a rigged CG mod- el, asked an actor to mimic Tintin's expressions from the comic books, and applied those ex- pressions to the 3D model. "Then, we began exploring changes," Stables says. "We changed the model's nose and gave Tintin cheekbones and a jaw. By the time we had a Tintin we liked, we had tried 1600 variations." In addition to the main characters, the modelers built hundreds of crowd characters. "We created new characters all the way to the end," says Marco Revelant, models supervi- the whole rig from a base model to the new model, and it's good to go. If we weren't happy with something, we'd fix it on the template and push it out to all the characters." For Avatar's nearly naked Na'vi, the crew had developed Tissue, a simulation system, to build muscles, skin, and fat. "It's a linear-elastic finite- element system," Clutterbuck says, "a stand- alone thing with a front-end bolted onto Maya so artists can interact with it. We plug anima- tion into the system and it adds the simulation on top; it's our tool set for deformation work." For Tintin, though, the crew pushed the system further to add dynamics to facial de- formations driven by the captured data and keyframed animation. The developers plan to submit a technical paper to SIGGRAPH 2012 on the technique. "We wanted wobbly cheeks, chin folds, skin colliding with itself around the facial area," Clutterbuck says. "To get that, we need- ed both dynamics and facial deformations. So we took what's effectively a series of blend- shapes rigged in the facial puppet and mapped them into the simulation system to add simu- lated elements to the face." To control the constraint-based simulation, Animators at Weta Digital started with performance-capture data for all the characters except Snowy, the little white terrier. Steven Spielberg directed actors who performed the characters on a motion-capture stage using a system at Giant Studios similar to the one James Cameron had used for . A Model Production A team of modelers that ranged between 40 and 60 people built the 4000 digital assets needed for the film, creating face shapes and deforma- tions for the animators and adding fur and hair to the characters. Modelers at Weta Digital work within an Autodesk Maya pipeline. Many modelers also sculpt using Autodesk's Mudbox, originally developed at the studio, and a few add Pixologic's ZBrush to the mix. Modelers moved back and forth between hard-surface models and characters, although one team specialized in fur and hair, and an- other in creating face shapes and deforma- tions. Also, the modelers gave the characters especially detailed hands. "We had amaz- ing reference—an MRI and a life cast of a guy's hands that we used to build new, high- fidelity hand models," Clutterbuck says. The main character, Tintin, had the most difficult face to model. "He's a balloon with two dark eyes and an oval mouth," says Wayne Stables, visual effects supervisor. "That worked 12 December 2011/January 2012 sor. "I remember adding a female character in the last month. We generate models from the same elements, even using the same topology for the main characters and the generic char- acters. The distinction between a main charac- ter and a crowd character is in the complexity of the facial system, not in the model itself. For the generic characters, we have an automatic way to generate a basic facial system." To rig the bodies, character technical di- rectors worked with a generic model, which they call "genman," a fully simulated muscle model. Two creature TDs rigged all the char- acters, one working on Snowy, the other on the human characters. "We hadn't done a dog, so that was a full- time job," Clutterbuck says. "But we had done a lot of development on bipeds for Avatar and had a good genman model. We used it on Apes, but we took it to an extreme for Tin- tin and built everyone from the same guy, all procedurally. We started with a surface model and used a process we call 'warping,' to fit artists painted attribute maps on the facial puppet. Clutterbuck gives an example: "We have a [jowly] character named Barnaby, and we have the performance for his chin and lips, but we wanted those areas to interact with his wobbly chin. So, instead of trying to do two separate solutions and blend them, this system unified everything. We painted little patches around his lips, and the attribute map set up everything once. After that, the simulation was procedural. The solver can also wobble, wrinkle, and buckle all at the same time. The animators didn't see any of this; they concen- trated on the performance." Perfecting Performances The animators received data for the characters' faces, bodies, eyes, thumb, index, and pinky fingers, captured performances that provided what animation supervisor Jamie Beard calls a "starting block." Beard worked on Tintin for five years, supervising the previsualization and then leading the team of between 50 and 60 animators. "We offered the director an animated and a live-action world," Beard says. "On set he could be a live-action filmmaker, blocking out the actors and directing them. Once captured, if the scene was perfect, we'd work on the per- formances only a limited amount to change them slightly if Steven [Spielberg] wanted to tweak them; directors being who they are A vat ar