The Cat In The Hat: Living In A Fishbowl

Living In A Fishbowl

When Universal Pictures releases The Cat In The Hat thisholiday season, Mike Myers will personify Dr. Seuss' famous feline.Myers will be sharing the screen with a talking computer-animated fish,and the challenge of making that fish come alive for director Bo Welchbelonged to L.A.-based Rhythm & Hues.

Of the 350 effects shots that R&H handled for The Cat In TheHat, 40 involved the animated fish. Visual effects supervisor DougSmith characterizes this animation as relatively stylized. “Themovie starts out with a real goldfish in a bowl, and then goes into the‘Seussian’ world when the cat shows up,” Smithsays.

Digital effects supervisor Chris Sjoholm describes the fish as,“a semi-cartoon character with realistic skin who lives in a realglass bowl with real water. When he's underwater he's quite glossy andiridescent, and the fishbowl reflects the whole room that he's in. Wealso see him hanging off the side of the bowl and he looks either wetor dry, depending upon whether he's out of the bowl long enough so thatthe water has seeped off of him.”

Universal's art department began the design of the fish with basicoutlines that, Sjoholm says, they expanded upon and produced 20versions. “We then built the model in the computer, and therewere lots of little tweaks. We had to determine how big his eyelashesshould be and how wrinkled to make his eyebrows.” Creating facialanimation, notes Sjoholm, “is difficult with a character thatdoesn't have a bottom lip!

“Once we had an approved turntable of a gray shaded model, theroad split at that point,” continues Sjoholm. “Some peoplewent off and defined the actual look and others defined the characteranimation.” The latter group studied videotaped references ofactor Sean Hayes reading the fish's lines. They also watched videos ofBarney Fife, which director Welch had identified as an inspiration. Thefish's performance subtleties would be noticeable because of his size.“He's so small that he's framed super tight to get all theemotion on his face,” Sjoholm says.

However stylized the performance, the fish's body had to seembelievable. “To make his skin photorealistic, we had independentmovement of the fish's scales,” says Smith. “That probablytook a month of R&D. We also spent about six months developing atornado-like vortex of water in the fishbowl. We brought in aconsultant from UCLA to help us deal with the fluiddynamics.”

“A lot of research has been done in Complex Fluid Dynamics,but every CFD paper has little cheats — no one has the ultimatesolution,” says Sjoholm. “For water in a fishbowl, therewas no ideal theory out there.” Simulating water can produceanomalies like the appearance of cavities or a volume of water thatexplodes while sloshing around. “There's ‘theory’ andthen there's implementation, and sometimes there are errors inboth,” Sjohom concludes.

The simulation team also spent lots of time throwing spheres intothe water, making sure they got good splashes. R&H's softwarespecialists wrote plug-ins to work inside Side Effects' Houdinisoftware for the water simulations, but most of the animation for thefish shots was handled within the studio's proprietary code.

The complex task of rendering was also done with an inhouserenderer. Because the fish often appeared out of the water —sometimes looking wet and other times dry — the lightingchallenges were complex. “We had a variety of issues dealing withthe reflections off the fish's scales — they had to look as ifthey were coated with a layer of goo,” says Smith. “Thereare also layers of iridescence on the fish skin that interact with thewater and are reflected in it. And because the character has largeeyes, we did refractions in them as well.”

Raytracing and some global illumination were necessary to achievethese effects. “We augmented our renderer to do the raytracingand sub-surface scattering and iridescence,” says Sjoholm.“We spent about four months doing R&D to tweak this. The raysbounce around far more than they would with a normal object. Every rayhas to go through the front of the bowl, through some water and maybesome waves to hit the fish. Then it has to bounce back again. Sothere's a lot of light reflecting in all sorts of areas. We had takenphotos of the environment on set and we reflected that environment onthe fishbowl too.”

Motion blur was also required to accentuate the fish's movement, andthe end results were huge render times. “We have a couple offrames where he's so streaked it took quite awhile!” Sjoholmadmits. “But there are efficiencies that we made every step ofthe way. The simplest thing was to break things down into layers, or wecouldn't afford to render this guy. The fish was broken down into theiridescence layer, the main skin layer, and other specular layers— there were seven layers in all. That was just for the thingsthat made up the fish. The refraction that happens inside the eyeballis very different from the gel layers coating the skin.” Tooptimize rendering speeds, the majority of renders were done on Linuxmachines.

The final step involved compositing all of this against live-actionbackgrounds. R&H primarily used its inhouse compositing softwareIcy, as well as Apple's Shake. “To make the fish integrateproperly with its surroundings introduced a whole other level ofcomplexity,” says Smith.

“We started out doing a far simpler fish,” says Sjoholm.“But as things progressed we threw in more and more because itstarted looking better and better. Before we knew it, we had a prettycomplex guy.”

Bo Welch - Director
Doug Smith - Visual Effects Supervisor
Chris Sjoholm - Digital Effects Supervisor
David Gutman - Compositor
Mike Sandrik - Lighting Setup Supervisor
Keith Roberts - Animation Supervisor
Jonathan Cohen - Principle Software Engineer
Joe Mancewicz - Animation Setup Supervisor
Caroline Dahllof - VFX TD
Toshi Kato - Principal Graphics Scientist
Peter Huang - Principal Software Engineer
Keith Hunter - Modeling Manager