Step by Step: Charlotte''s Web

In E.B. White's classic book Charlotte's Web, one en- dearing scene shows Wilbur the pig receiving a buttermilk bath. For Paramount Pictures' live-action film version, director Gary Winick used this moment to spotlight a comic turn by another star critter — Templeton the rat. While the milk drips from Wilbur, Templeton sneaks into the tub beneath the pig and floats on his back, slurping a free meal. He licks his whiskers, rolls his eyes, and blissfully observes, “I've had these dreams!”

While a real pig was filmed, the rat was completely animated in 3D CG at Tippett Studio in Berkeley, Calif. “The rat beneath Wilbur is a punchline,” says Visual Effects Supervisor Joel Friesch, who devoted two years to Charlotte's Web. “The shot starts with Wilbur's body, and then the camera drifts down to reveal Templeton. It's a one-shot gag. But because the scene includes a real pig and real milk, if our rat didn't look real it would blow the shot.”

Once the plate photography was delivered, Tippett's team had to maneuver Templeton underneath the pig, yet keep it out of shadow. “He's a dark rat so you need to see details. Otherwise it could look like something different — we've all watched Caddyshack,” Friesch says.

Autodesk Maya was used to track the plate photography, and also to animate Templeton. “We had to jump through hoops to make him funny and endearing,” Friesch says. “There's a fine line between ‘acting’ and maintaining real rat mannerisms. Rats actually can swim, but they don't like water. Templeton had to be lovin' this, so we had to base the gag on how a person would float and splash in a pool. But we put in as many ‘rat actions’ as we could to sell the joke.”

Friesch knows real rat behavior from personal experience. “We had a live rat here for the entire production. I actually took our rat to the sink and poured warm water over him,” he says. “I'm glad I wore gloves.”

Observing wet rat fur was crucial to creating a believable appearance. While Templeton's motion was hand-animated, his floating fur was created with Tippett's proprietary software Furocious. “It runs by a series of guide splines,” Friesch says. “We style those and then the computer fills in hairs between those guide splines. We control it using things like texture mapping. We have both 2D and 3D tools within Furocious. We can bend fur one way or the other, make it longer or shorter, change its color, and make the strands stick together or push away from each other. We pretty much used all the different parameters and attributes with Templeton.”

Furocious works with both Maya and Pixar RenderMan, and that helped integrate the character into the plate photography. But it was a significant challenge to manipulate the buttermilk on which Templeton floats. “We made a CG milk surface for our effects animators to use, but we found that a 2D displacement of the plate worked better than adding CG milk,” Friesch says. Tippett's painters set up the surface to resemble the photographed buttermilk, and used paint tools such as Adobe Photoshop and the freeware Deep Paint. While the studio primarily runs the Linux OS, painters use Macs as well.

To augment and replicate buttermilk drips, the effects animators used proprietary liquid simulation plug-ins, as well as Next Limit's RealFlow and Maya Dynamics. “We created our own splashes and drips coming from the pig, and also did ripples that originated from the rat,” Friesch says. “We dropped milk into Templeton's 3D fur to make it move. The milk would hit the surface of the rat and run through the fur. In order to show the tension of the two surfaces adhering to each other, we did both 2D and 3D fur displacement.”

“[Once the simulations were complete,] we'd render Templeton in his entirety,” Friesch says. “We'd run multiple channels off of that render, running different maps that we knew we'd need. We could blur his whiskers, or lighten or darken his feet if need be. We had to mess with his whiskers a lot because we'd lose his whiskers in the color of the buttermilk as he splashed. A rat's whiskers are very characteristic of his face, so they're something we wanted to see. We animated the whiskers so they're kind of stuck in the surface tension of the milk, which helps integrate him into the scene.”

A final key attribute of Templeton was his tongue, which was crucial to the delivery of his dialogue. “Because there's milk dripping and his ears are going in and out of the milk, Templeton's tongue helps you find his face,” Friesch says. “One of our notes from the director was that when Templeton sticks out his tongue, it wasn't readable.” Friesch credits creative compositing — done using Apple Shake — with finding the solution. “We had a very creative comper who did lots of 2D — like cutting things out of the plate and reanimating them in 2D,” he says. “We did a 2D tongue to make it more readable. There were many comp tricks in this shot.”

The end result — somewhere between 200 and 300 frames — turned out to be one of the most challenging of the 230 Templeton shots in the film. Sadly, their living “reference rat” passed on around the time Tippett's team wrapped Charlotte's Web. The crew gave its mascot a fitting burial on the studio's grounds. “His grave has a beautiful headstone,” Friesch says.