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Issue: Volume: 29 Issue: 5 (May 2006)

Oh Rats!


CG Short - In this year's SIGGRAPH best in show, artists go to extremes-dark/light, real/fantasy - to create a compelling animated short film.
By Barbara Robertson

"One Rat Short," a 10-minute animated film, focuses on extremes—repulsion and love, dark and light, realism and fantasy. It’s the first 3D animated short created by Charlex, a New York-based digital design and post production studio, and it won the first competition in which it was entered: the prestigious SIGGRAPH Computer Animation Festival.

"I was just hoping we’d get into the Electronic Theater," says the delighted director, Alex Weil. "One Rat Short" took that hope to the max by winning Best in Show over 726 submissions. The film now qualifies to compete for an Oscar.

"The jury felt this piece achieved greatness on several levels: emotionally, technically, and artistically," says Terrence Masson, SIGGRAPH Computer Animation Festival Chair. "We viewed hundreds of quality films, but this one stood out to all members of the jury. The audience connects with the central characters on such a level that the film stays with the viewer for days afterwards. Clearly with record submissions this year, it was not an easy decision—which speaks to the merits of this piece.

"The all-CG film begins in the dark. It opens with rats scurrying around subway tracks; it has the feeling of live-action film noir. The gritty background looks like it might have been a live-action plate; the camera feels handheld. But the camera moves to rat level and follows one dirty rat chasing after a bag of chips, and it becomes clear that this is an animated film. The bag leads the rat on a dangerous journey into a slick, bright, whiter than- white laboratory. There, he falls in love with a pure-white lab rat. There’s no dialog in the film; no jokes. The animals look and act like real animals for the most part. And, it has a film-noir ending.


                            
Lighters rendered scenes in EXR format to give compositors awide dynamic range to work with. By using
extremes of light, from the dark opening scenes outside in a rat pit (top left), to the bright, white lab inside (right),
the director pulled viewers into his CG short. Befitting the film-noir story, the rats were animated and rendered as
animals, not cartoons (bottom).


"One of my goals was to make a film that was not like a Pixar film," says Weil, an Emmy-winning director and Charlex founder. "Their work is so great. But there are so many imitators now. I wanted to do a New York-style animated film. I wanted to use CG to capture emotions that aren’t usually captured by CG. I’m tired of the voices making the jokes. I wanted to tell a story about a rat, the most repulsive of all creatures, and I wanted it to be a love story, not a cartoon."

That wasn’t his first idea, though. Three and a half years ago, when a team first began working on the film, it was called"Labratz," and Weil had in mind the kind of cartoony film that he later rejected. His turning point was seeing the dark subway scene realized by production designer Todd Winter and lead lighter John Parker."It was created to my direction," Weil says,"but when I saw it, with the camera feeling handheld at rat level and the filthier-than- filthy, darker-than-dark look, I realized I wanted to do my movie with a minimum of anthropomorphic animation."

The simple story allowed Weil to experiment with light. "With so much in the dark, viewers have to lean into the story," he says."They have to fill in the gaps with their imagination; it’s easier to imagine themselves as the character. In the bright parts, they almost have to look away because it's so bright they almost can’t see the character. I tried to make it so you have to make a story in your mind."

Doing so, however, was not so simple. The studio spent nearly two years in visual development, in part because the crew was working on the film between jobs. About a year ago, Weil and Chris Byrnes, Charlex president, decided to create a separate division with a dedicated staff of 15 people. "We rented half of another floor in our building, and put the team there," says Byrnes. "That’s when things got focused."

Improv in the Pipeline

The "Rat" team included several people who had worked on feature animations at such studios as Blue Sky and DreamWorks. They tried to help Weil understand how a standard pipeline for a CG-animated feature works. "We tried to usher in the standard techniques—start with a script, then do storyboards, layout, modeling, and so forth," explains Bryan Godwin. "We found out that with [Weil’s] style, it was more efficient to jump into 3D straight off the bat. We blocked the whole film in 3Dwithout going to paper first.

"Weil calls it "writing the movie in camera."Rather than moving shotbyshot from storyboards or animatics, animators working in Autodesk’s Maya created the camera’s viewpoint and performed the characters from plot point to plot point. They knew the objectives, but not the shots in between. Because they didn't work from a layout with a locked off camera, they moved the camera freely for Weil and played with focal depth.

"If you want a film to feel like live action, the camera has to feel like a human being is moving it," notes Winter. Weil improvised and refined the story and the camera movement along the way, collaborating interactively with the animators and lighters, and editing online with Autodesk’s Discreet Smoke. The happy accidents that resulted from the interaction among the animators, editors, and Weil—and a lot of attention paid to camera curves—helped give the film its handheld camera feel.

"It was a very organic process,"explains Weil. "I discovered much of the visual writing as I did the film; a lot of the storytelling is in the way the movie looks and feels. We couldn’t previz the whole movie because the texture is part of it, too." That meant Weil wanted to see lighting early in the process as well, so the animators used Maya play blasts—OpenGL renders—to give him a sense of how the scenes would look after rendering.

"He works in a fast-paced commercial world, and he’s used to seeing animation and lighting live," says Winter. "From my experience in the feature-animation world, that’s unheard of, so we had a lot of adapting to do. We had to create play blasts early to get as much mood as possible." They developed other techniques, as well. For example, because the play blasts allowed only a limited number of lights, to create the mood for one dramatic shot, the lighters stretched transparent polygons through the scene to create fake light beams.

Godwin believes that the process helped the film makers achieve the movie’s distinctive look and feel. "When I first started working with [Weil] on the commercial side," he says, "I thought it was crazy that he wanted to work live with animators. But when I got over my initial fear, I realized we got a lot done and more quickly. We often put animators live in a room with the client and editor. They could look at 10 versions a day and think more creatively. Many times, we’d see an animator tumbling a viewpoint and say, ‘That’s it, that’s the shot.’ I’ve learned that taking a unique approach to making a film results in a unique film."

Tools and Techniques

For reference, the animators had a pair of pet rats in the studio;the characters in "One Rat Short" were rigged like animals, not humanoids. And yet, they’re actors, not cartoon characters. In fact, the crew named the subway rat Cagney and the white female rat Audrey. The crew grew and groomed the rats’ fur with Maya's tool set, and developed a custom solution for rendering the fur in Mental Images’ Mental Ray. "The rats aren’t real, but we wanted to make sure the viewers empathized with them," says Winter.

To animate crowds of rats—in the rat pit near the subway, in lab cages, and running on the floor of the lab—the Rat team developed custom simulation tools within Maya. One tool made the rats scatter, for example, and another streamed animation cycles in and out. Animators could fill ll cages with idle caged rats in the background and put a more active colony into a shot;they could randomly select cycles for particular parts of a crowd, and could "kill" rats that behaved badly.


Rim lighting added in Digital Fusion outlines
the stars for a tender moment. Cage lights
behind were rendered in Mental Ray and
baked into textures.

The film's lighting team relied on Maya lighting tools, Mental Ray shaders and scripts, and Eyeon Software’s Digital Fusion, with which they composited layers rendered in 32-bit fl oat through Mental Rayin EXR format. "We had a huge range of contrast in terms of exposure," says Godwin.

Lighters started with color keys that Winter painted in Adobe's Photoshop and with the play-blast lighting created in Maya during the production process. Then they created beauty passes that Winter often enhanced further. "I’d grab a frame and paint it one more time to communicate exactly what we were looking for," he says.

To create the brightly lit lab that also had lights in each cage, the crew baked in much of the lighting. Then, they added lights in Maya to the baked textures and, later, in Digital Fusion, integrated the powerful glaring light. Inside the lab, red lights and color indicated danger, and magenta warmed a tender moment; otherwise, everything was white except for Cagney, the subway rat.


Red lights make the lab robot stand out in the otherwise
laboratory; they also signaled danger. Lighting was accomplished
with Maya, Mental Ray, and Digital Fusion.

Outside, lighters and compositors rendered the dark, filthy world in desaturated blues. "Most of the feature animations have bright colors because they’re directed toward kids,"explains Winter. "We wanted to make sure our film stood apart from that. So early on, we decided to go really desaturated."Inside and out, rim lighting added in Digital Fusion helped lift the characters from the background. A Digital Fusion filter pushed an orange-red glow into the chip bag, giving it a magical quality. "It represents faith," says Winter.

Next Moves

In addition to letting Weir fl ex his directorial muscles, the studio had other reasons for making the film —to attract talent, upgrade technically, learn how to work faster, and give its clients more creative choices, according to Byrnes. "We’ve had steady growth over many years," he says. "This film seemed like a natural progression. Now, we’re interested in longer-format projects and features, and it’s nice to know we can do them."

Any feature directed by Weil would likely be as unique as the 10-minute short. "I think if I did a feature, I would want to do a somewhat dark film ; if there were to be humor, it would be more urban," Weil says.

But would Weil expect to use the same organic process of working interactively with the animators, lighters, and editors to develop the story for a feature animation? Yes and no. "I had to learn what everyone knows—that the story is king," he says. "So I would begin with the story and believe in it. But, I can only change so much—a lot of good came out of working the way we did."

In "One Rat Short," a door closes on an opportunity for one of the characters. The opposite extreme is likely to be true for Charlex. "This is only a 10-minute piece, but we’ve gained con-fidence that we could produce an independent feature," says Byrnes. "We’re keeping our options open."




Barbara Robertson is an award-winning journalist and a contributing editor for Computer Graphics World.
She can be reached at BarbaraRR@comcast.net.

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