THE DARK KNIGHT: VFX Breakdown Of Batman's Sonar

The Dark Knight | Visual Effects Making Of from BUF on Vimeo.

For The Dark Knight, BUF was assigned the spectacular opening shot of the film and new intriguing challenge from director Nolan, the creation of Batman's "Spy Vision". In the film, Bruce Wayne develops a new technology that is able to detect the electromagnetic waves emitted by cell phones. By scanning the waves' behavior in space, the device allows Wayne to visualize in three dimensions any environment in which a cell phone is turned on

Since nothing like this exists in the real world, it was up to Pierre Buffin, VFX Supervisor Dominique Vidal and the team to figure out what this technology could look like. "We started with the concept of sonar." Vidal remarks, "Except that you can't see a sonar wave. So, we did tons and tons of tests. We tried waves, metaballs, smoke, particles, etc.” This testing period involved intensive collaboration between BUF's in-house R & D team led by Xavier Bec and lasted eight months. This research allowed BUF to be extremely efficient in the execution of these shots, the subsequent production period for the shots lasted only four months.

"Chris Nolan wanted the waves to bounce back off obstacles, but also to partly travel through them. In addition, the device needed to feel harmless, and not look like X-Ray. We considered allot of different details of what this could look like, for example: how fast should the wave go? how much of it should bounce back? how fast it should deteriorate? how it would dissipate? etc.," Vidal continues. "In the end, we managed to find the right combination of wave frequency, speed and rhythm. It was basically a CG wave on which we added some noise. All our work on the movie was created using proprietary software."

BUF also designed the environments in which the "Spy Vision" is used. This wave animation plays a key role in the Prewitt building sequence, where Batman uses it to locate hostages. The device is also featured in the Batcave monitor room, where dozens of monitors visualize different locations -- an environment reminiscent of the Architect Room that BUF created for The Matrix Reloaded.

The first step was to build each environment by modeling layers upon layers of geometries, because in Spy Vision, all volumes are translucent except when hit by a wave. "We had to see across the rooms all the way through, including the city in the background with traffic in the streets, etc." Vidal remarks. "It was amazingly complex. And we had to do it for each one of the monitors in the Spy Vision scenes in the Batcave. It was a very detailed for something that was only meant to be part of the background, each screen had to show people with phones doing different activities. In order to get enough material, we filmed our families, our apartments, our offices, etc., using BUF's proprietary pipeline to shoot references for the key frame animation. The amount of work that those Batcave monitor room shots required was insane!".

Finally, BUF had to prepare the shots to be rendered for IMAX resolution. This unique requirement added an enormous challenge to a project that was already very challenging. VFX are usually created at a 2K resolution but full IMAX resolution exceeds 8K x 6K, with a single uncompressed frame representing around 200 Mb of data. BUF treated IMAX resolution at either 5.6K or at 4K anamorphic, depending on the shot. 3D renders and 2D elements were created at one or the other of these resolutions. "It is much heavier to handle, but in the end, you really obtain a quality that clearly sets the movie apart from anything that one can see on a DVD at home," Vidal notes.