The live action was shot over four days, with the cars speeding across the natural landscape of the Victorville, California desert. While A52 supervisors managed the placement of tracking points from which to gather data, a stainless steel ball recorded environmental lighting cues in nearly 360 degrees. Drawing more data for the "air as water" effect, the crew dropped black models of the vehicles into water tanks to compile footage that would be composited with animation. Ultimately a hybrid of CG and recorded footage, many of the effect's properties were modeled after images that Mathieu created in Photoshop during the bidding process, while Inferno artist Simon Brewster worked closely with him on tests to emulate the vision.
Lead artist Denis Gauthier used Houdini for animation and Renderman for rendering; extensive scene manipulation and compositing was conducted with Discreet Flame and Inferno. "In every shot where there was a vehicle, we tracked the scene using a 3-D equalizer that replicates the entire shot in the computer," says Gauthier. "Then we placed models over the image in the photography. That way, the water really can wrap around the car."
To create the blinding light that reflects off of the turbulence, the effects team took cues from the live action footage, but ultimately aesthetics won out. "We would just do what we thought was nice. There would be a sparkling highlight where the sun should be, sometimes many degrees away from where the sun actually was," says Gauthier. The team devoted time and study to extrapolating how the effect would behave in different situations to ensure consistency. A52 producer Scott Boyajan says, "We would do one scene, and then we had to start seeing a sequence to start understanding what the effect is doing and what it would do 100 feet behind the car." This was especially true for the climax of the spot, when the four newest Cadillac vehicles stop at a crossroads and the four "water tunnels" meet and swirl around, creating a circular wake.
"The effect was very hard yet easy in a way," says Gauthier. "The one thing that's challenging with water is splashing and filling voids, but our water didn't do that because our director didn't want it to act exactly like water. It was challenging because our turbulence was something that didn't exist."