Born to be Wild
Issue: Volume: 28 Issue: 5 (May 2005)

Born to be Wild

If you believe the startling success of 3D animated features forevermore pushed 2D cartoon-style animation out of full-length films, you haven’t been paying attention. The ’toons have snuck back-inside 3D films.

Last year, for example, the CG characters in two features performed some flashy 2D moves. The fish in DreamWorks Animation’s Shark Tale acted in a cartoony manner (see “Reef Madness,” October 2004, pg. 14). The superheroes in Pixar/Disney’s The Incredibles-Elastic Girl, in particular-stretched 3D models beyond anything on-screen before (see “Hero Animation,” November 2004, pg. 18). And now, with Madagascar, PDI/DreamWorks has ratcheted up the action by freely applying 2D animation principles to all the stars of its 3D film. Madagascar is a 3D ’toon.

Four years in the making, the comedy feature-which stars Ben Stiller as the voice of Alex the lion, Chris Rock as Marty the zebra, David Schwimmer as Melman the giraffe, and Jada Pinkett Smith as Gloria the hippo-opens in a daydream. Marty is swinging on a vine while an instrumental version of “Born Free” plays in the background. He somersaults over a canyon and wakes up to the sound of voices shouting, “SURPRISE!” He’s in New York City, in the Central Park Zoo at his birthday party.

Buoyed by his dream of living free, Marty escapes. When Alex, Gloria, and Melman realize he’s gone, they track him down through the streets of Manhattan. The four escapees are caught in Grand Central Station, surrounded by police, shot with tranquilizers, crated, and put on a ship sailing to Africa. On the way, the zoosters’ crates tumble overboard. The former city dwellers find themselves washed ashore on a wild tropical island populated by Aye Aye lemurs and predatory fossas.
The zoosters Marty, Alex, Gloria, and Melman grasp their dilemma.

“The story line is simple,” says Tom McGrath, who co-directed the film with Eric Darnell. “The lion and zebra are best friends in New York. When they’re in the wild, they have to overcome nature, which tests their friendship. But half the fun is getting there.” The fun started with character design.

“I’d never seen anything like this pulled off in 3D,” says Rex Grignon, head of animation, pointing to early drawings of Alex. Before working on Madagascar, he was supervising animator on PDI/DreamWorks’ Shrek and Antz, and while at Pixar, an animator for Toy Story.

“For me, the question was whether we could find a unique animation style that fit the production designs,” Grignon adds. “The characters had to do big, broad poses, every pose needed to have personality and attitude, and the animation had to be very snappy. These are traditional animation tricks, but there was no touchstone for what we wanted to do in 3D. We knew we’d have to distort the models, bend them the wrong way, stretch their torsos, squash them. It was scary.”

For example, Gloria, a hippo with a big belly and short little legs, stretches twice her length, touches her toes, does karate kicks over her head, lies down on her back, and moves her belly without moving her hips. Marty the zebra walks on all fours and also stands up like a human. Melman the giraffe stops as he walks along and scratches his neck with his leg.

Moreover, all the characters were drawn in ’toon style with, as McGrath puts it, “straights against curves.” The top of a penguin’s wing, for example, has straight lines, but the bottom is curved. “That’s easy to animate on paper but hard in 3D,” he says, “because when the character turns, it looks bizarre.”
At top, animators matched the 3D zoosters’ graphic design with snappy 2D-style animation. The incorrigible penguins (below) were the snappiest.

“A few years ago, just getting basic animation with 3D was a challenge,” adds Darnell, who previously directed the short film Gas Planet and PDI/DreamWorks’ first CGI feature, Antz. “Now, we’re pushing the limits. The inspiration for this film was Tex Avery-style classic 2D. It’s never been easy to do this in CG.”

PDI/DreamWorks’ animation system, which won a scientific and technical Oscar, made it possible. “We’ve put a lot of investment in the rigging system,” says Andy Hendrickson, head of animation production technology. “So, it wasn’t ‘oh, my god, we have to do this.’ It was, ‘We finally get to.’”

Rather than mixing discreet shapes, animators control a system in which a character builds its own model in every frame (or, more often, builds only the part that changes). The animators, in effect, sculpt the characters. Once sculpted, the characters are skinned automatically with a mesh made of springs and points that relax the skin over the model.

“This method of animation is a controlled simulation,” says Hendrickson. “With other systems, sticking Melman’s neck out at a weird angle would take thousands of animation shapes and sculpts to create the poses, and cracks and weird wrinkles in the skin would result.” Instead, the software code in this system uses instructions provided by animation controls to build the exterior of the creature. “That is essential for doing squash and stretch without having rigs coming apart,” he says. “And, the skin is really a skin, an exterior mesh that goes over the creature. It isn’t knitted-together topology.”

Thus, the riggers held the key to creating Madagascar’s characters: They designed a system of animation controls that could move the geometry into the graphic shapes the animators wanted for poses and that allowed extreme motion in-between the poses.

“It was a collaborative effort,” say Jim Mainard, head of R&D. “We had a vision, and the underlying technology is as flexible as a programming language, so basically we could create anything we could conceive. The riggers spent a good deal of time writing scripts and using plug-in libraries to get the shape and motion right.”

The riggers used animation controls themselves, as well, to create a variety of characters for crowds. “We started with two models-one round, one sharp-and we deformed the geometry with animation controls,” says Milana Huang, character TD co-supervisor. “We just applied animation to get many shapes.”

For the main characters, the riggers began organizing control systems by first working with the character designers. “We wanted to see how they cheated,” says Rob Vogt, a character TD co-supervisor. “Where they placed the shoulders, how they maintained the arc.”

Adds Huang, “We noticed, for example, that when the faces were squashed and stretched in 2D, they’d lower only the part from the nose down, and raise only the part from the eyes up.”

All told, the animators had between 200 to 300 controls on the faces and hundreds more for the body and hair, organized into macros. Melman’s cheeks could puff out, for example, his mouth could gape open, and his muzzle could move independently from the rest of his head. Animators were able to make major adjustments with one control, or drill down to control something specific.

Vogt points to his screen where Alex had become, in effect, a stack of seemingly disconnected boxes that represented body parts. “He can be organized in any way the animator wants,” Vogt says. “An animator can move his hips without affecting his shoulders.” Animators see these blocks moving apart when they’re working, and then can push a button to see the character redrawn with its skin stretching to accommodate the movement. The riggers call it goal-oriented regional character posing.

“The main challenges,” Vogt says, “were the extreme ranges of motion. We needed to squash and stretch the faces and bodies, yet maintain the silhouette. It couldn’t look rubbery. The scaling had to be very specific.”

“One trick was to have the character look normal when your eye is soaking it in, but when it moves, to do what serves the animation,” says Grignon. For example, Alex’s arm might stretch and grow huge as he swings it toward the camera, but when he stops, it looks normal again. To help animators, the riggers added procedural controls to handle scaling issues automatically.

Animators can now have 3D characters perform the types of exaggerated moves that are typically drawn on paper for 2D cel animations but are rarely possible in 3D.

“The rigs were super dynamic.” Says Grignon. “We could do anything to any character any time. It was a big adjustment for the animators, but we gave them intuitive controls.”

For example, most CG characters have eyes modeled after human eyes, which have two “corners,” one on each side of the eye, where the lids meet. To help create cartoony expressions, riggers gave animators shutter-style four-corner eyes with lids that could have straight or curved lines. To maintain Gloria’s full belly silhouette, the R&D team created a special deformer that preserved her volume as she moved. And, to make it possible to animate Alex’s “pound cake” fingers, the riggers added automatic scaling because otherwise, the fingers were too thick to bend at the knuckles.

Once it became clear that animation could be as stylized as the character design, the story became zanier and more graphic. When Alex is shot with a tranquilizer dart, he hallucinates a kaleidoscope of graphic shapes. Onboard the ship, the animals are in their crates proscenium-style (in front of the curtain) alone against a dark background. And, the characters could act more like ’toons.

“We weren’t thinking completely unleashed,” says McGrath, “but we let animation be a character. And the style opened the door to slapstick comedy.” When the zoosters land on the beach, for example, they’re still in their crates. “We asked, ‘What’s the wackiest, funniest way to get Melman out of the crate?’”

In addition to the characters, some unusual “cast members” played a supporting role: the effects. “The effects told our jokes,” says McGrath. And, Darnell adds, “They had to match the style of the film. We couldn’t have boilerplate effects.”

That doesn’t mean the effects were simple, however. The lighting and surfacing crews handled painting and lighting for environments from urban shots in Manhattan to the Madagascar jungle.

To help create this complexity, the crew developed a procedural tool to quickly put arbitrary geometry into a layout. “[The tool] had some notion of the distance from one thing to another,” says Hendrickson, “so you could populate a scene with random quantities of things in all sizes and shapes.”

They could, for example, plant a jungle. “We didn’t use comp tricks or cheats for the foliage,” says Hendrickson, “so we created geometry-wrangling tools to define areas of geometry and the levels of detail we’d apply.”
From top left to bottom right: Camera moves and performances are approved in rough backgrounds. A matte painting and then layers of jungle rendered from back to front add detail. At bottom right is the final scene.

The geometry was necessary because the plants were always moving-such as when touched by a breeze or in reaction to character movements. In one scene, a blast from the ship’s horn nearly flattens 14,000 plants that have four million deforming leaves.

“We basically used non-dynamic deformations,” says Scott Singer, head of effects. Layers of plants organized into a hierarchy were tuned with different levels of motion. Noise shaders created ambient motion, and a deterministic oscillation shader produced a vague sense of character interaction. For more direct character interaction, the crew used a system called “bushwack,” that added high-level deformers. But, if a character needed to interact with a plant, that motion was keyframed by the character effects department.

For crowds, which appear in two-thirds of the sequences, effects animators moved characters using animation cycles and rule-based flocking behaviors, or they moved them on motion paths and sometimes with specific choreography. The crew used displacement maps to dress human characters created by the riggers, but human crowds weren’t the big problem.

“When we started, we could render only five lemurs,” says Philippe Gluckman, visual effects supervisor. Optimizing the fur renderer helped them to handle as many as 50 at a time, as did a rendering trick: They put shells that had same volume as fur around background lemur bodies, ruffled the edges with displacement, and created a fur shell shader that responded to light as if it were fur. A new compositing program helped layer the jungle and, often, as many as 500 lemurs together.

“We weren’t trying for realism,” says Gluckman. “Effects were art directed and choreographed.” Although the studio has an award-winning fluid simulator, the ocean’s motion was keyframed.
A new fur shell shader helped render crowds of 500 furry lemurs.

“We kept coming back to effects that didn’t use dynamics,” says Singer. “For the ocean, we keyframed the profiles and derived wave geometry from the profiles using curve animation and surface extrusion. It was refreshing for the crew. When we asked what the ocean should look like, instead of hearing, ‘Like water,’ we were told, ‘The ocean is foreboding and lonely.’ Or, ‘The dust is funny.’”

To make funny dust, the crew created spiral shapes with rounded angles-straights on curves. “The shape was used throughout the film,” Singer says. “You see it on characters’ noses, on the ends of logs. So we applied it to the dust. If you look, you’ll also see little spirals in the mist, the smoke from the ship, and spit.”

Spit? Lots of spit. “We have a series of spit takes that we probably overuse, but it was really fun,” says McGrath.

“So many effects tools have been written to solve physics problems,” Singer says. “On this movie we had to throw many of them out. The effects animators would say, ‘How am I supposed to animate?’ The answer was, ‘By hand.’”

In the past, because it was simply too difficult to create 3D models that could be bent out of shape without breaking, animators performed 3D puppets rather than pushed much-loved extremes to convey emotions and sell story points. By removing the limitations that 3D had imposed, PDI/DreamWorks allowed character designers, animators, and effects artists freedom to tell stories in new ways by using a new-old style within a 3D world.

Barbara Robertson is an award-winning journalist and a contributing editor for Computer Graphics World.