The digital team worked on creating on-set systems that allowed the actors to drive in motion bases so they would feel like they were in real cars. CG cars and environments were then placed around them.

"The experience has been very freeing. The all-digital pipeline is very, very close and I think this movie was one of the first where the transition was relatively smooth. This felt like the first time the technology didn't hinder in any way what we were trying to do and enabled us to have a great deal of creative play with the images. That to me was one of the most exciting aspects of it."

Look development on the visual style and car design originated with Gaeta, Glass and Libreri and Mohen Leo (two other Matrix alumni) at Industrial Light & Magic before Libreri and Leo moved over to Digital Domain. Leo worked on setting up the systems on set that allowed the actors to drive in motion bases to permit them to feel like they were in real cars and then would have CG cars placed around them; they weren't just Digital Domain's shots, but also other vendor shots too. But they set up all the technology for that. Digital Domain also set up the animation previs pipeline for the cars so that the previs team could work with cars that would ultimately be transferrable into post.

"We did proof of concept animatic test for designing tracks from the normal to the super wacky inspired by modern videogame and anime aesthetics as far as loop-d-loops and other spirals, hump backs, spiders, massive drops, cars falling off the tracks and doing aerial combat," says Libreri. The production inevitably coined the term "Conveyor Belts" to describe the infinite loops of road to put CG cars on. Overall, Digital Domain worked on 445 shots, 300 of which were fully CG.

"In Berlin, the art department had around 20-30 cockpits that were mounted on a hydraulic motion base in front of greenscreens and a number of systems there to allow the directors to view the cause and context of the backgrounds," Leo explains. "Encodacam was there with a system and Brainstorm so that when the actors were sitting on the motion base in front of a greenscreen, the directors could frame the shot and get a live preview of the cars around the actors. And we had a variety of systems to steer the motion base to give the actors the sense that they were driving and get the correct camera moves using everything from traditional live waldos and joysticks to pre-programmed moves on the Cooper system to a high-end car simulation racing engine called rFactor from Image Space. It's a very open system and we worked together with them to create an interface between rFactor and the Cooper System at the motion base. We had the ability to actually place a car on one of the tracks. For example, we built Thunderhead as a full 3D track in rFactor so that with a steering wheel and pedals behind a gaming system [you could] drive around the track and then record the accelerations and the motions of the car out of the simulator and feed that onto the motion base to get the appropriate motion like a series of turns around the track. Another thing the simulator allowed us to do was give the directors a gaming pad, which we mapped the buttons to, allowing them to simulate the car being hit by another car or jumping and landing for the car fu action. The simulator was a great help to Second Unit Director James McTeigue, who could see our stunt drivers driving around and give them instructions. The actors tried a live test from the cockpit that allowed them to drive while viewing the track from the simulator on the monitor, but it was too difficult for them to act and essentially play a videogame at the same time."

Digital Domain additionally set up a new mental ray rendering pipeline. "The amount of technology that went into our global illumination [was immense]," Libreri continues. "Using traditional methods to render our cars using mental ray would take about 10 hours a frame; they got our renders down to about 10 minutes a frame for cars simply by doing massive optimizations to the global illumination code for mental ray. Maya was our front end for cars and animation and rendering and Houdini was used for effects animation. Both mental images and Autodesk helped us take the Maya integration to a new level. And Atomic is our new lighting engine that fits on top of Maya that acts as a layer and light manager."