The impressive effects were a combination of CG, 2-D and live action, done at London's Framestore CFC. According to animation supervisor Andrew Daffy, the process grew out of director Kleinman's highly detailed animatic, which referenced scenes from nature documentaries and films like Waterworld. The spot's dramatic opening scene features a tremendous swarm created in CG and comped into live-action backplates. Daffy and his crew animated five key figures in Maya, which were then multiplied using a shoaling system, not unlike the flocking system used for the tremendous fighting scenes in Lord of the Rings. The animation crew created swimmers with three body types each for men and women, but like the stunt people, the animated characters also had to move as if they were beyond human. "Normal animation starts from the hips," explains Butler. "If you're going to make someone walk, you move the hips, then the legs, then the torso and arms, and in the end you put the head on. Trying to animate a person being a fish doesn't work that way." Framestore created a new setup that allowed for a ripple movement from the head down through the hips and the legs. The system also enabled the animators to quickly tweak and vary the swim speeds. The variety of characters, and some noodling in Inferno helped to create the randomness crucial to the spot's realism, explains Murray Butler, who co-supervised effects with William Bartlett.
The midshot and closeup scenes required mixed media. Shot in Australia, about 10 swimmers wore invisible flippers and were sometimes pulled along a winch to vary speed and enhance an arms-free and graceful fishlike movement, a detail Kleinman was insistent upon. The live-action shots were then matted, multiplied and comped into the backplates with additional animated swimmers.
Framestore and Kleinman captured the climactic "dolphining" scene almost entirely in-camera. Stunt swimmers donned flesh-colored corsets that were tethered to a barge via wires. Multiple cameras on the barge shot the swimmers at various angles, as crew members used the wires to bungee them out of the water as they swam. The live shots were as crucial as the postproduction in contributing a sense of authenticity. "We're not really precious about the idea that 3-D has to be used," says Daffy, "but I think we found a new extreme sport for maniacs who like to do this kind of stuff."