Longer and edgier than any of its previous work, Pixar's latest film benefited from a production pipeline more akin to a live-action feature. 3D World unmasks the technology that gave 'The Incredibles' its superpowers.
Opening to rave reviews and a box office of $70.7 million (second only to Shrek 2), Pixar's The Incredibles secured the studio's 100 per cent success rate, with all six of its animated films reaching the top of the hit list. Usually spawning U-rated features, Pixar stepped into new territory with this PG-certified tale of a superhero family stuck in the suburbs - and it worked. The Incredibles had the fourth biggest premiere for a superhero movie ever, right behind Spider-Man, Spider-Man 2 and X2.
The comparison to those live-action superhero movies is apt. Although The Incredibles is a CG feature, Director Brad Bird created a film with live-action attitude, plotting camera moves on storyboards, dividing the crew into first and second units - and even 'shooting' his characters as if they were on a greenscreen stage. Although the three live-action superhero films were based on comic books and The Incredibles isn't, the characters' designs reflect a comic-book style, not the style many expect from Pixar. In a sense, Pixar made a Brad Bird film; Brad Bird didn't make a Pixar film.
The film follows Mr. Incredible (Craig T. Nelson) from his marriage to Elastigirl (Holly Hunter) to their downfall and subsequent move to suburbia in a Witness Protection program. The former Mr. Incredible becomes Bob Parr, office worker, and Elastigirl becomes Helen Parr, mum to daughter Violet (Sarah Vowell), son Dash (Spencer Fox), and baby Jack Jack, all of whom have superpowers. The film also stars Samuel L. Jackson as the voice of ex-superhero Frozone, Jason Lee as the villain Syndrome, and Brad Bird himself as Edna E. Mode, the family's costume designer. Bird first brought the idea for The Incredibles to Pixar four years ago. Although a departure from its normal U-rated fare, the studio immediately got behind the project. "I knew my story would be protected," he says, "I could put all my energy into making the movie, not defending it."
Moving with Bird to Pixar were John Walker, The Incredibles' producer, who had worked with Bird on Iron Giant at Warner Bros., and Storyboard Artists, Mark Andrew and Andrew Jimenez. "Brad loves story guys who are strong stagers," says Walker. "The storyboard is not about dialogue; it's the movie. Andy was working in After Effects."
At Pixar, Supervising Technical Director Rick Sayre became Bird's liaison with the studio, acting like a visual effects supervisor on a live-action film. "At the start, I worked with the director to understand the film and the production process we'd need," he says, "I looked at what kind of R&D and outside tools it would take, and then just rearranged everything. Our motto was, 'Welcome to The Incredibles: we're still figuring it out.'"
From the start, Sayre and the Pixar crew had their hands full. Not only did the script call for more human characters than ever created at Pixar before, but also the film was almost 15 minutes longer than any of its previous efforts. Bird's storyboard style helped out here. "The storyboards were more like live action than animation," says Sayre. "They had timing, pacing, and camera moves. So, because he had specific notions about what he wanted, the layout department had a different role to that on a conventional CG movie: they offered suggestions; they didn't invent camera moves from scratch."
Bird explains the difference: "John [Lasseter] likes to be free to move the camera anywhere he wants," he says. "He likes to play with it. I like to flesh out the idea in the story reel, to get a feeling of how it's paced early on." For example, for A Bug's Life, directed by Lasseter, Pixar built an entire island and then, as Sayre puts it, "sent out location scouts" who looked for good camera angles. In contrast, the crew on The Incredibles team knew where the camera would be in advance, and therefore built only the models needed for particular shots, saving needed production time.
"We wanted to make the biggest movie [Pixar had ever produced], but we didn't want it to cost more," says Bird. "The only way to do that was to know exactly where the camera was so we didn't build anything extra. If the camera moved two virtual inches to the right, the shot would have broken down."
HOLY LIVE-ACTION, BATMAN
In addition to building sets from camera view only, the Pixar crew also borrowed the idea of first and second units from live-action filmmakers. First-unit teams were the animators who worked on hero characters and sets; second-unit teams comprised effects animators.
This separation of first and second units had some interesting consequences for the production pipeline. The shot during which Edna describes the new superhero suits to Helen, for example, was even staged like a live-action shot, with the animators treating the characters as if they were on a greenscreen stage. Separately, the second unit built the lab behind them and composited it into the final shot. Because the two units were working independently, they could even use entirely different software. Helen and Edna were built in Maya, rigged and animated using Pixar's proprietary tools, and rendered with RenderMan, while the stretchy suit behind the window in the lab was a 2.5D matte painting created with 3ds max and rendered with SplutterFish's Brazil rendering system.
"It was great fun," says Sayre. "Liberating. I think every freaking tool in the world got used here and there. It was the least 'in camera' film that we've done. Usually we poke the render button and out comes the shot. [With The Incredibles] we poked the render button and out came a bunch of elements for compositing." For this purpose, Pixar primarily used Shake, with an occasional shot assembled in After Effects. The studio also, in Sayre's own words, "cheated like crazy." Among the cheats were (whisper it) practical effects. "We used live-action water that we filmed in a kiddie pool when the baby is in the sink," he says. "And we filmed trees to create shadows on the wall."
"When Brad first came here," Sayre adds, "he said the one thing that drove him crazy was that people built spaceships when it made more sense to throw a damn saucer." But although Bird's live-action inclination may have helped the production team cope with the ambitious project, his stylised human characters presented numerous new challenges.
"We had two opposing ideas," says Bill Wise, Character Supervisor. "The characters were cartoony in shape and proportions, but they needed to be believable as humans. And since many of them were superheroes, they had to perform in wild extremes." So not only did the characters need to have muscles, but Elastigirl needed to stretch and twist her arms. Bird also wanted a cartoony squash-and-stretch animation style for the other main characters. And if that wasn't bad enough, there were 12 of them.
The characters were modelled in Maya and rigged using proprietary systems. "The challenge was in the rigging," says Wise. "We developed a template with basic rotates at major joints that could be applied quickly to characters so that we could easily apply musculature to them. Every character referenced the template, and changes to the template would propagate to all the characters."
All character rigs included something called 'bendbow'. "The characters could not only bend at the elbow and wrist," explains Mark Therrell, Character Articulation Artist, " but we could take the angle and smooth it; shape it into an arc or a curve. When an arm is moving through a fast arc, instead of motion blur, which is a fake arc of colour, the animators actually shaped the character into the arcs." Thus, the animators could exaggerate the characters motion using a graphic, Tex Avery kind of style.
For Elastigirl, who needed extreme bending and stretching, a special rig based on a new curve deformer [see p. 29] allowed animators to shape her arms into arcs, curves, zigzags or loop-the-loops. Because Bird wanted the audience to see the turmoil Elastigirl goes through when she decides to use her stretchy superpowers, a simple morph wouldn't do. "One of the biggest challenges for Elastigirl was that we needed an appealing attractive woman that we could articulate in a traditional way using joints, elbows, wrist, knees, and girly features," says Mark Therrell, Character Articulation Artist. "I then needed to figure out a way to transition this attractive human rig into a monsterlike thing that still looked elegant, slender and feminine while doing something humanly impossible."
To do that, he created two rigs: The first was a normal rig that was articulated in the usual way in Pixar's proprietary animation software. The second rig was a separate 'snake' rig that used the new curve deformer with a duplicate of Elastigirl's geometry. The 'snake' duplicate was piggybacked onto the normal rig. "The curve skeleton deforms another version of Helen that you never see exactly like the real Helen minus hands, feet and head," says Therrell.
The team would animate Helen normally, like any human character and then when they wanted her to make stretchy movements, they just flipped a switch. "Suddenly, Elastigirl was doing the same thing but with a completely different rig," says Therrell. "They could take the tabs - the control points along the curve - and constrain objects and also have objects constrain to them." In addition, they could translate the tabs up and down a curve like path animation, so that her arm could snake out, for example, and wrap itself around a telephone pole.
When animators wanted Elastigirl to go back to Helen, they animated all the control point values back to zero, the control points moved back into place, riding piggy-back on the skeleton again, and the animators could then blend back to the skeleton. "It was like a magic trick," says Therrell, "they'd flip the switch when you didn't expect it."
Another 'magic trick' turned Elastigirl into a parachute: "We took the curve deformer into another dimension," says Therrell. "Instead of curves, we used flat surfaces and had a little gingerbread man-style of surface that moved with the normal Helen skeleton. So, not only could we do a chewing gum linear stretch, we could blend to a malleable 'parachute Elastigirl.'"
MUSCLES, SKIN AND HAIR
Most of the characters also needed muscles to look believable, so a musculature system was built on top of their rigs with skin that slid over the muscles. The bones moved the muscles, which were deformer objects attached to bones at two points, and the skin dragged along - a standard type of muscle-skin simulation system for CG characters. Animators typically create the performance with this type of dynamic simulation, and then technical directors run the muscle and skin simulations. Pixar animators, however, wanted to see the muscles as they animated. "They didn't want to give up control of the silhouette," says Sayre.
Skin simulations don't run fast enough for animators to see the results in real time, so Software Engineer John Anderson and Pixar's tools group created an alternative method using an entirely new technique: statistical modelling. This produces a model based on data rather than geometric transforms; the shape is based on probability - a best guess inferred from previously calculated results. Statistical modelling also allowed animators to see how the characters' costumes looked in motion for any particular performance based on previously calculated dynamic simulations.
For cloth and hair simulations, the crew used an engine originally developed by Andrew Witkin, David Baraff, and Michael Kass to create Boo's T-Shirt and Sully's blue fur in Monsters, Inc. They updated it to meet the demands of The Incredibles by, for example, adding methods for controlling the hair simulation. "Hair was part of the characterisation," says Wise." For example, Bob habitually runs his fingers through his hair and Violet hides behind hers. In one scene, Helen tucks Violet's hair behind her ear - a familiar motherly action and very difficult to simulate.
To solve the problem, Pixar had to dramatically redevelop its hair technology. "The core simulation did evolve," says Anderson, "but mostly we were developing new kinds of internal and external forces. In addition to the pure simulation technology, we made a lot of targeting and parameter adjustments." A character's hair could be sculpted into a rest behaviour, for example, and attracted to a keyframe.
"We also worked on keeping movement coherent," says Anderson. "You can't simulate every hair but when you replace the bulk properties, the hair tends to lose coherence." This became especially important in a scene that sent Helen and Violet swimming underwater, Violet's hair flowing behind her.
Another difficulty with hair was lighting it. "The shadows created by strands of hair needed to be at full density so you could see the separation," says Janet Lucroy, Director of Photography. "But the characters had translucent shadows unless the scene was very graphic. So we handled the hair with extra fill light."
For the soft, translucent shadows themselves, the crew used ambient occlusion judiciously. "Only where we got the most bang for the buck," as Lucroy puts it. "When Helen puts her hand on Bob's arm, we get a lot of payoff."
Throughout the film, the lighting crew also used contact shadows. "Our motivation for using them for the dark line in nooks and crannies was that if two things should touch each other, it doesn't matter where the light comes from," says Sayre. "No light gets there." In each case, the lighting artist decided whether the contact shadows would be baked or computed every frame. "If Helen and Bob are facing each other, the contact shadows are computed," explains Sayre. "If the shadow is caused by a picture frame on the wall, we can bake it."
In most 2D animation, characters eyes are brightly lit and faces are seldom in shadow. But this film had lighting that ranged from natural to theatrical. "Brad's point of reference was inspired by live action, action movies, and film noir," says Sayre. "We have strong harsh shadows on faces where we see only one eye. The lighting accentuated or toned down the graphic forms of the characters." For example, when Mr. Incredible stands in front of a wall of red lava, he's so starkly backlit that he's just a black shape. But domestic scenes such as Helen and Dash riding home from school, a family dinner, and other scenes at home were lit softly. "The lighting didn't call attention to the characters," Lucroy says. Because there were so many locations in the film, the crew devised techniques that allowed lighters to work more interactively than before. "We were in outer space, on an island, underwater, and in a city," says Bird. All told, there were 179 master lighting setups, which compares to 56 for Monsters, Inc.
Illumination Engineer Daniel McCoy worked on technology that would approximate final renderings quickly enough for the crew to see the lighting effects interactively. "We would render images with lighting parameters that corresponded to the surface under each pixel and then bake them out," he says. "If the surface was skin, it would have lighting parameters for skin; if it was a carpeted floor, it would have those lighting parameters."
"When a light was moved, the images would be updated with hardware rendering," he continues. "So the lighters could drag a light around and get a close approximation of the look they wanted. They could change the colour of the light, the intensity, the shape, and even reflections." Although it was designed to help lighters with master setups, the system was used for shot lighting as well. "The lighters would do the first 50 per cent interactively, and then switch."
What the system couldn't take into account, however, was Subsurface Scattering. For this, the team applied the same ideas used for muscles and cloth so that it became a fast off-line process that was informed by a statistical analysis of the character. When it came to skin, the designers were in a quandary. "The character design was difficult," says Bird. "CG looks plastic without detail, but beyond a certain point with the stylised deformed people, it starts to look creepy. So we went with less detail in the pores and more in the Subsurface Scattering."
Pixar films typically push state-of-the-art computer graphics in new ways. Toy Story proved that a 3D feature film could not only be made, but it could be a smash. The short film Geri's Game introduced the graphics community to Subdivision Surfaces. And when Boo pushes her little hand into the fur on Sully's shoulder in Monsters Inc., Pixar demonstrated how hair simulation could make a story point.
For The Incredibles, Pixar solved two major problems: creating and animating oddly-shaped yet believable 3D human characters in a cartoon style, and producing a film with many of these characters in every frame (and in numerous locations) without breaking the bank. Pixar's technical wizards created new tools - a spline-based deformer, statistical modelling algorithms, and a hardware-based interactive lighting tool - and the production crew adapted live-action techniques such as the concept of first unit and second unit teams. As a result, with The Incredibles, the studio that gave birth to CGI feature films proves that 3D animated films can now offer the creative flexibility of live-action films - given the proper tools and an inventive team.