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Double Negative Recreates United 93 Flight

London-based Double Negative helped director Paul Greengrass realize his documentary-like vision for UNITED 93, the story of the fourth plane to be hijacked on Sept. 11, 2001, opening today (April 28, 2006) from Universal Pictures and Working Title.

Double Negative (HARRY POTTER AND THE GOBLET OF FIRE and BATMAN BEGINS) was in charge of 483 shots, which were completed in just six weeks. The short deadline required precise planning at every stage and a highly efficient working pipeline to deal with the logistics of the massive workload and a constantly evolving film that was still being edited until the final days of the schedule. Matt Plummer, Double Negatives vfx producer, said, In the VFX industry we are all used to working to short deadlines but a six-week turnaround for this standard of creativity is a fantastic achievement, especially as this was an evolving project with many changes made throughout the post-production schedule.

The film is a meticulously researched document that attempts to portray the real events as they unfolded on board Flight 93. The result is a raw but sincere testament to the events that ushered in a scarier world. The use of un-known actors, and scenes developed through rehearsal rather than scripting, was married with a documentary approach to the filming (handheld cameras and long uninterrupted takes) to produce a raw you-are-there experience. The shooting style precluded the use of usual vfx techniques of tracking markers and meticulous noting of camera and lens set ups.

Double Negatives CG supervisor on the film, Rick Leary, commented, There was a complete lack of contrivance in the way the film was shot; they used an improvisational shooting style involving a lot of handheld camerawork on multiple cameras and the visual effects had to link in with that. This made the work more of a challenge than usual, but hopefully the pay-off is that the shots feel very natural.

The overall brief for the vfx was that all shots matched the emotional language and feel of the film, and therefore went unnoticed. Plummer added: The aim was to make our visual effects contribution to the film completely invisible to the audience. This film isnt about visual spectacle, and our job as vfx artists was to do all we could to maintain the integrity of the performances on screen.

The tension of the film builds as United 93s passengers board the plane and then as it is delayed on the runway. The creation of the runway and exterior environment of Newark Airport made up approximately fifty percent of Double Negatives work. The basis for these shots was limited footage from a number of American airports; in most cases this could be used as a guide only with the majority of any particular shot being created digitally, from the planes, tarmac and airport buildings, to ground-staff vehicles and distant highway traffic.

Double Negative was provided with foreground elements of a plane and ground crew, which was shot on a runway in the English countryside, but even this plane had to be replaced with a computer-generated United 757. In addition, all the shots, which were filmed in murky English weather, had to be digitally re-lit or graded to match the brilliant sunshine of Sept. 11.

Once the plane was airborne the bulk of the shots were greenscreen window replacements. This work played a crucial role in the storytelling by geographically locating flight 93 throughout the film. As the passengers recognize landmarks that are incongruous with a flight to L.A., they realize something is wrong. Then, as they try to take over the plane, the hijackers violently pitch and roll the plane. In order to ensure consistency across shots in this sequence, a single CG environment of landscape and cloudscape was created. The landscape was derived from aerial photographs manipulated in Dnegs proprietary environment tools. This approach ensured the seamless sense of the planes erratic and violent descent in spite of the frenetic camera movement and cutting from shot to shot.

A team of 45 Double Negative artists worked on UNITED 93, who also coordinated four other U.K. vendors completing work on some of the simpler shots.

Since its formation in 1998, Double Negative ( has firmly established itself as a leading player in visual effects production worldwide. Located in the heart of Londons Soho, the company is a pre-eminent visual effects studio with more than 40 feature films to its credit.

Bill Desowitz's picture

Bill Desowitz, former editor of VFXWorld, is currently the Crafts Editor of IndieWire.