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January 27, 2007

Web Design

chWebDesignCGWdec06.jpgThere have been an impressive amount of coverage on the visual effects work done on Charlotte's Web, and I'm so glad to see it!

here is yet another article on the visual effects work that helped bring this children's classic to the live action arena:

Computer Graphics World's | Web Design

"Tippett Studio faced when creating Templeton the rat, the two CG stars of Paramount Pictures live-action version of EB White's classic children's tale Charlotte's Web. Director Gary Winick was adamant that the characters not be portrayed as stylized, cuddly creatures, but instead wanted them to look photoreal so they would blend seamlessly with the rest of the animal cast. He also wanted the audience's reaction to the characters to mimic that of Wilbur the pig, which is averse toward Charlotte and Templeton at the beginning of the story but grows to like them as the story progresses."

A realistic CG Carlotte and Templeton act alongside a real baryard case in the latest iteration of Charlotte's Web
When most people see spiders and rats, they immediately think creepy, scary, repulsive, and gross.

So how do you get movie-goers of all ages to form a warm emotional attachment to a spider and a rat that look so authentic they could pass for the real thing?

That was what Rising Sun Pictures (RSP) faced when creating Charlotte the spider and Tippett Studio faced when creating Templeton the rat, the two CG stars of Paramount Pictures’ live-action version of EB White’s classic children’s tale Charlotte’s Web. Director Gary Winick was adamant that the characters not be portrayed as stylized, cuddly creatures, but instead wanted them to look photoreal so they would blend seamlessly with the rest of the animal cast. He also wanted the audience’s reaction to the characters to mimic that of Wilbur the pig, which is averse toward Charlotte and Templeton at the beginning of the story but grows to like them as the story progresses.

To tackle the challenge, the studios used a combination of top artistic talent and robust digital tools. The result is a photorealistic arachnid and rodent that viewers can’t help but fall in love with, just as author EB White intended.

Endearing Designs

Set to hit theaters in North America just before Christmas, Charlotte’s Web features a bevy of barnyard animals—geese, sheep, cows, horses, and, of course, a beloved pig named Wilbur. All of these animals are voiced by actors, and they appear in the film either as well-trained live-action critters whose mouths move thanks to CG mouth and face replacements, or as realistic-looking animatronic replicas. Even Wilbur is a real pig in all but a few stunt shots, where he appears as a CG pig created by Digital Pictures Iloura.

In fact, apart from the baby spiders, which debut at the end of the film and were created by Fuel International, only Charlotte (voiced by Julia Roberts) and Templeton (voiced by Steve Buscemi) are always portrayed digitally, primarily because both characters had to give numerous specific performances that were key to the story line and that would have been impossible to elicit from a real spider and rat.

To be true to the story, Winick wanted Charlotte and Templeton to possess an on-screen presence that would cause viewers to eventually form genuine feelings of affection for them, without breaking the illusion that they were as real as the rest of the cast. One way he sought to achieve that goal was to have each character go through a complete story arc. For instance, in her first scene, when she catches a fly and drinks its blood, Charlotte is viewed as somewhat of a monster, revolting to all the barn animals, including Wilbur. And the audience has to go from sharing that feeling, to becoming as enamored with her as Wilbur becomes, and then being completely shattered emotionally when she dies at the end of the film.
Likewise, in Templeton’s first scene, he lets out a huge belch, making his barn mates and the audience believe that he’s nothing more than a distasteful slob. But as Charlotte, Wilbur, and the audience get to know him, they see that deep down he has a heart of gold, going out of his way to find words for Charlotte to spin into her web in an effort to save Wilbur from becoming Mr. Zuckerman’s pork dinner, and eventually helping Charlotte save her babies.

The artists made Templeton photorealistic, but toned down the modelsomewhat to make him appear less gnarly yet defi nitely not “cute.”

The other way Winick sought to achieve his goal was to ensure that the characters looked real but didn’t repulse the audience. "That was our biggest challenge when creating Charlotte," says John Dietz, visual effects supervisor at RSP. "We had to ensure that she looked like a real spider, but make her appealing to viewers of all ages."

Blair Clark, who supervised the visual effects at Tippett Studio with Joel Friesch, concurs. "We had to get the point across that Templeton is a real rat, but not frighten people in the audience who may have rat-phobia."

To do that, both teams took the same approach when designing the characters: aim for photorealism, but slightly stylize a few features to make the characters more endearing. After several months of design work, countless meetings with the director, producers, and Paramount executives, and numerous sample models, the artists finalized their designs.

Charlotte would be a photoreal gray spider with eight eyes, a plump, hairy body, eight hairy legs, and a pair of blood-sucking chelicera. But because many of her shots are close-up performance shots, her photoreal facial features would be stylized slightly to make her more lovable and to enable her to convey emotion. For example, the designers gave her face a subtle heart shape, and they made all eight of her eyes almond-shaped to suggest femininity. In addition, above each of the two main eyes, they placed a pair of secondary eyes representing eyebrows, to help her emote.

The designers also took some liberty with the hair on Charlotte’s body and legs. "At the macro level, the hair on some spiders is kind of spiky, and we decided to keep that look for the wide shots. But for the close-ups, we designed a downy, fawn-like quality to her hair, to take a bit of the edge off," says Dietz.

Likewise, Templeton would resemble an authentic rat, with thick fur, a long tail, long gray whiskers, and sharp teeth. According to Clark, defining the color of Templeton’s fur proved somewhat difficult. "Initially the studio was leaning toward a cute, almost mousy rat, and at one point they talked about making him white or light gray," says Clark. "But Templeton is supposed to be a sloppy, greasy, filthy character, and we wanted him to look the part.

"Wilbur’s story arc is about not being judgmental, about acceptance," Clark continues. "And if Templeton was a cute, little, white lab rat, why wouldn’t Wilbur like him? Why would he view Templeton as untrustworthy in the beginning?" In the end, the artists got approval to make Templeton’s fur gray/brown in color.

As RSP did with Charlotte, the Tippett artists also toned down some of Templeton’s features. For instance, they didn’t make the toenails on his front feet as long as those on a real rat. "We had to cut them down so he didn’t look so gnarly," says Sven Jensen, modeling supervisor.

Jensen adds that to make Templeton more endearing, the team made his eyes a bit bigger than those of a real rat, and made his eyes turn inward slightly so that when viewers see him straight on, his eyes appear to be looking at them. Plus, his head is a bit broader than the long, thin shape of a real rat’s head, and they gave him a bit of eyebrow to make his eyes more expressive. "All of these very slight design tweaks were handled with a lot of forethought," Jensen notes. "We were extremely careful not to turn Templeton into anything even slightly resembling a cartoon character, or make him Disney-cute in any way."

Creating Charlotte

Once they had made all their design decisions, the teams began the process of modeling the characters. According to Dietz, RSP used Softimage’s XSI to model, groom, animate, and light Charlotte. While modeling her body was fairly straightforward, he says that modeling her face was more complicated.

"We built a standard rig for her body, but we did her face with blendshapes," Dietz explains. Although Charlotte is a spider, she talks and conveys emotions like a human would, so first the team had to figure out where the basic muscles beneath the skin of a human’s face would map onto a spider’s face. Then the group built blendshapes in XSI to drive those muscles, and combined them to form various facial expressions. In total, the team created about 500 blendshapes for Charlotte’s face, which they translated to a slider interface for the animators.
"It’s challenging to get a believable performance out of a CG character," says Dietz. "Charlotte isn’t running around, destroying a city. She’s on-screen for extended periods delivering pretty intense dialog. We did everything we could to ensure that she would deliver the performance the director was after."

While Charlotte looks like a real spider,the team at Rising Sun Pictures tweakedthe model, giving her a heart-shaped face,for example, to make her less scary.

As most modelers can attest, it’s hard enough to create a hairy critter. But add the complicated texture of a translucent exoskeleton directly beneath the hair and the task becomes more daunting. As such, determining how the hair and exoskeleton on Charlotte’s body would look was quite challenging.

According to Dietz, the team tackled that challenge using XSI’s hair/fur tool, grooming tools, and lighting system, as well as the 3Delight RenderMan-compliant rendering system from The 3Delight Team. All the hair modeling was done on a low-res proxy of Charlotte’s body. "Then we gave her hair systems that represent spiky hair, downy hair, leg hair, body hair—a variety of hair types," he says. With the hair/fur tool in XSI, hair is applied all over the character so it resembles a Chia pet, and then the artist grooms the hair to look the way he wants. "The software gives you guide hairs, and you define denseness, length, and other parameters for them. During rendering, the software interpolates what needs to happen between the guide hairs," Dietz says.

The biggest animation challenge with Charlotte, according to Dietz, concerned the way her face moved as she conveyed emotion and spoke. "Spiders don’t have human-like mouths, but there’s a line separating a spider’s face from its chelicera, and we felt that line would be good to use as a mouth line," he says. "To give the impression that she was smiling or frowning, we’d change the angle of that line slightly."
Of course, the process of conveying Charlotte’s emotions went deeper than simply tweaking the angle of the mouth line. As Dietz explains, the animators spent a lot of time learning the meaning of each shot and the emotions the director was trying to convey, and then they built an animation library of emotions in XSI. "The audience has to understand all of Charlotte’s emotions, and so did the animators. When she’s happy, what does that mean? What does she do with her posture? Her face?" he says. "Only after all the animators were clear on how Charlotte would convey emotion were they allowed to touch a shot. It was quite a process."

Charlotte is complex, both inpersonality and in structure.Pictured here are the variousstages that eventually resultedin the fi nal look (far left).

Just as spiders lack human-like mouths, they also lack anything resembling lips, so the animators didn’t have to contend with lip sync. However, they did have to give the illusion that Charlotte was talking. To do that, they implied that a mouth existed behind the chelicera. "As Charlotte speaks, the chelicera flare out a bit and you get the feeling from the movement of those fangs that there’s a mouth moving behind them," Dietz explains.
Yet, it was difficult to determine how much to animate the chelicera as Charlotte spoke. "Our first reaction was to hit every phoneme, but real speech doesn’t work that way, so we made only the major phonemes result in movement," Dietz recalls. "The hardest part was to not be tempted to treat the chelicera as lips and end up moving them in an exaggerated way, but instead to pretend that an imaginary mouth was behind the chelicera and that they would move as a by-product of the movement of that imaginary mouth."

Not only is Charlotte hairy, but she also has a translucent exoskeletonunderneath the hair, which was created with Softimage’s XSI.

To light the character, the artists used the lighting tools in XSI. To get the data from XSI to the 3Delight rendering system, they wrote a proprietary RIB exporter called Affogato. All the compositing was done in Apple’s Shake.

Tackling Templeton

As with Charlotte, modeling Templeton’s body was fairly straightforward. For reference, the Tippett team used pictures of rats, as well as a real rat, named Splinter, which they brought to their offices just for this project.
After the modelers built a completely bald Templeton in Autodesk’s Maya, the model made its way to the paint department, where the team painted a basic skin layer onto it, primarily in Adobe’s Photoshop, Right Hemisphere’s Deep Paint, and Maya. Then it went back to the modelers, who used Tippett’s in-house proprietary tool called Furocious to create and groom Templeton’s fur.

(From top, l. to r.) Matchmovers create a CG duplicate ofthe set to properly place the rat. The furless rat, with colorand markings similar to the fi nal, lets artists see the model’sform during animation. The animated model is furredand lit. A close-up lets the team examine their work.

Once the modeling and fur grooming were complete, Jensen built a facial rig in Maya consisting of approximately 280 blendshapes. The animators, using Maya, were able to combine and tweak those blendshapes to create all the different facial expressions needed for realistic speech. "In animation, we’d make poses—combinations of those blendshapes—to represent phonemes and different emotions," says Todd Labonte, animation supervisor. "Then we could bust through that combined phoneme list and quickly create an initial face pass without having to animate every muscle on the face."
Templeton comprises a variety of different blendshapes. For instance, the ones on his face resemble sliders that move the corners of the mouth and the eyes to convey emotion. But the ones on his body comprise corrective blends. "Instead of a muscle system in Templeton’s body, we used a lot of corrective blends to give him a baggy rat look. So, when he raises his knee, for example, his knee blends into the fat in his belly. That really added to his realistic look," Labonte says.

In this scene, the CG Templeton bathes in digital buttermilk. The realistic liquidwas created using a mixture of Maya, Syfl ex, and photographic elements.

In addition to using Pixar’s RenderMan for rendering and lighting and Shake for compositing, the team also used Syflex LLC’s Syflex and Next Limit’s RealFlow for dynamics simulation. Syflex, for instance, was used in a shot in which Wilbur is being bathed in buttermilk in anticipation of his appearance at the county fair. "As Mrs. Zuckerman bathes Wilbur, she wrings out the sponge and the milk flows down Wilbur’s back," Clark recounts. "We tilt into the pail and you see Templeton lying on his back, floating contentedly in the buttermilk." According to Clark, the buttermilk was created using a combination of Maya, Syflex, and photographic elements of various liquids, and compositor Chris Morley handled the compositing in Shake.

Effects animator Konstantin Promokhov, meanwhile, used RealFlow extensively in a shot in which Templeton winds up covered in the contents of a rotten goose egg. In this shot, Templeton cons one of the geese into letting him have an egg that failed to hatch. He rolls it into his lair, and he eventually gets it positioned exactly where he wants it. But then the egg comes loose from its position and breaks over Templeton, covering him in a gooey, smelly mess. "It was challenging getting the yolk to flow realistically over the rat and [his] bedding," Clark says. "But [Promokhov] handled it well in RealFlow."

Another challenging effects shot involved Templeton saving Charlotte’s egg sac. "In this shot, Templeton uses his teeth to gingerly pull the egg sac from the middle of a web and then carry it away," Clark says. "This required a lot of complicated layering of effects animation, but Rosa Lin, lead effects animator, created several layers of webbing [in Maya] that had the gorgeous diaphanous gauzy look we were after."

Webs and Crows
In addition to Charlotte and Templeton, RSP and Tippett also used their talents and tools for other elements in the film. One of these was Charlotte’s beautiful webs, which RSP created using XSI and some proprietary web tools the team developed for the project. "Creating Charlotte’s webs was difficult," says Dietz. "Humans have tried to re-create web material for its tensile strength, and they haven’t been able to do it. It was hard to create in CG something that people have failed to create in the real world."

The crows, like the rest of the animal cast, are mostly real, with CG mouthreplacements. But sometimes the crows are CG, crafted in Maya.

According to Dietz, the team used their web tools to assign the different strands of the web different properties. "Webs are made up of anchor lines, which are very strong; spoke lines, which are strong but aren’t of the same consistency and quality as anchor lines; and orbital lines, which are very loose and are the parts of the web that bugs stick to," explains Dietz. "All three are different, and we needed to create a complex dynamics system to get them to interact realistically with one another, to animate realistically in a breeze, and to react appropriately when a fly gets stuck in the orbital lines, or when Charlotte walks around on the web and her feet stick to the lines and pull them, and they snap back when her feet let go."

Dietz adds that the team also treated the webs as a character in the film. A major part of the story concerns the words which Charlotte spins into her webs in an effort to save Wilbur’s life. In the beginning, when she comes up with the plan to save Wilbur by spinning "Some Pig" into a web, she’s at the top of her game and she’s good at what she does. "When the web is complete, it has a special quality to it lighting-wise [created in XSI] to give you the feeling that it’s a special web," Dietz says. As she ages, however, her webs lose some of that special quality to imply that she can’t spin as well as she used to.

Even after Charlotte is gone, her webs remain, but they are old, gray, and tattered. "These webs also required special dynamics, which we created using our web tools to make them sag and move like they’re aged," Dietz says.

Tippett, meanwhile, also was responsible for animating the crows in the film. According to Labonte, the group used Maya on beak/head replacement shots of live crows, to make it look like they were chatting with one another.

Other times the team worked on shots in which the crows are entirely CG. As Clark explains, Templeton and the crows don’t get along. In one scene that takes place at the fairgrounds, Templeton coerces some crows to fly at him, but instead they fly into a scarecrow. When they do, a net falls on top of them. "In this series of shots, effects animator Uma Havaligi had to combine the real plate with a greenscreen element of the scarecrow that we shot, with two CG crows on it flapping around, covered by a CG net that had to conform to their bodies," Clark recalls. All of the CG models were built and animated in Maya. To create the feathers on the crows, the team developed a feather tool within their Furocious software. All compositing was done in Shake.

A CG net also played a role in another complicated shot, in which Templeton traverses a bridge made of a ping-pong net. "It was a complicated shot because we have Templeton walking over a bridge, bouncing up and down on this net surface," says Labonte. "We found ourselves in a chicken-and-egg scenario where the lead animator, Jason Armstrong, animated Templeton and simulated the net, but then the net was bouncing differently than Templeton, so he had to re-animate Templeton to the net, and then re-sim the net, and then the net was bouncing differently than Templeton—it was a crazy infinity loop of insanity."

To solve the problem Labonte says the crew stopped simulating the net freely and began deforming it locally to Templeton’s specific actions. "[Armstrong] provided a rough animation of the bridge, and the effects animation department then simulated small surface ripples in it," he says. The net was built and animated in Maya, while all the compositing was done in Shake.

All told, the folks at RSP and Tippett Studio note that bringing this latest incarnation of Charlotte’s Web to the big screen was truly a labor of love for everyone involved. "It was hard work, but we’re very proud of the results," says Tippett’s Clark.

"Charlotte’s Web was a great movie to work on animation-wise," concludes RSP’s Dietz. "Having the opportunity to create a CG character that has personality was an outstanding experience. And I am very proud of how our team got into the character and into the process of making a movie, and not just doing special effects."

-Computer Graphics World's | Web Design

Audrey Doyle is a contributing editor for Computer Graphics World.


Posted by dschnee at January 27, 2007 10:56 PM