Cinefex Weekly Update | Issue 38

Much like the protagonist of Shark Tale, the story of a fast-talking little fish whose big dreams land him in a whole lot of hot water, DreamWorks nearly bit off more than it could chew three years ago, when it dreamed big and decided to produce the CG-animated film at its Glendale facility -- whose infrastructure at the time was primarily geared toward 2D animation. "We had Shrek 2 in production up north at PDI/DreamWorks," recalled Shark Tale visual effects supervisor Doug Cooper, "and we couldn't risk disturbing that schedule by taking people from that film and bringing them back here to feed the production process. So we decided the smartest thing for us to do was to build a new pipeline for Shark Tale around the tools that the talent base in Los Angeles was familiar with."

Charged with creating stylized, snappy performances, animators made use of the character rigs' built-in 'squash and stretch' capabilities in order to achieve a look not ordinarily seen in 3D character animation. "It's an exaggerated style of expression that 2D animators have been doing really well for years," remarked Cooper. "A lot of what's been accomplished in computer graphic animation is making stuff look realistic. We've got dinosaurs and aliens that look completely real. But we were not going for that. We were going for something that felt fun and had a lot of energy to it, something that you don't normally get to see with shading and textures and real lighting on it."

The new proprietary lighting and rendering pipeline -- a hybrid system that used both RenderMan and mental ray in an innovative way -- would also prove invaluable in supporting the film's delicate balance of real and stylized. "It wasn't a push-button solution," explained Cooper. "It wasn't just set up your lights and do a simulation that runs for hours and duplicates exactly what happens in the real world." The approach, pioneered by DreamWorks CG supervisor Mark Wendell, took advantage of mental ray's ability to produce rich and realistic lighting detail, but in such a way as to give the artists greater control over the final effect. "We computed all of our beauty render passes in RenderMan, while mental ray was used to compute bounce light and what we call exposure mapping, or ambient occlusion. We built a pipeline that actually connected the two renderers together; but with our system we could set up our initial lighting in RenderMan, then bake through any bounce lighting we needed. We would have already prebaked all the exposure mapping, so when we went to do our beauty passes, incorporating the bounce light and exposure maps, we only had to work within RenderMan. That allowed us to get a lot more interactive control over the look and the style of global illumination, without enormously long render times." Artists also wrote custom shaders to produce the shimmering iridescence of the sea creatures, mixing those with subsurface scattering techniques, which gave characters -- particularly the jellyfish -- their soft, translucent quality.

For Cooper, a nine-year veteran of DreamWorks whose stint on Shark Tale was his first time out supervising a fully CG-animated feature, the assignment was an opportunity to explore unique visual territory. "I loved Finding Nemo," said Cooper, reflecting on the inevitable comparisons likely to arise between Pixar's underwater tale and DreamWorks' latest undertaking. "I think it's a beautiful movie. But what we've done here is a very different thing. It's not the same story, the design is nothing like it, the mood of the film is nothing like it, and it doesn't look like it. I feel pretty confident that what we've done is something unique."