Alain Bielik reports on Les Chevaliers du Ciel, the most ambitious photoreal vfx movie ever made in France, thanks to the noteworthy work of La Maison.
Ask any Frenchman who Tanguy and Laverdure are, and he will surely answer that they are the title characters of one of the most enduring series of graphic novels ever, covering more than 39 albums published over a period of 45 years. Telling the adventures of two French Air Force pilots, the series proved so popular that it was adapted into a now-cult television series in 1967 under the evocative title of Les Chevaliers du Ciel (Knights of the Sky). Thirty-eight years later, the series has now become a feature film helmed by Gérard Pirès, director of the original Taxi. In order to emphasize the difference between both series and the movie, the name of the characters has been changed to Marchelli and Valois.
The movie opens with a new mission for the two pilots: retrieve a Mirage 2000 the French equivalent to the F-16 that went missing during an air show. When they ultimately locate it, the rogue pilot engage combat and is finally shot down. Marchelli and Valois investigate this dramatic incident and draw a shocking conclusion: their unit has been infiltrated by a terrorist organization that wants to use one of the Mirages to strike the President during the traditional air parade of July 14th (France National Day). However, the conspiracy theory is deemed too extravagant by the authorities. With July 14th approaching, Marchelli and Valois only have a few days to prove that their theory is right
Seeking the Ultimate Aerial Footage
Having piloted the most diverse types of aircrafts himself, including the legendary Sukhoi SU-27 jet fighter, Pirès was an ideal candidate to direct the ambitious movie. Knowing his work would inevitably be compared to Tony Scotts on Top Gun, the director elected to capture the most realistic depiction of jet fighters in action ever. This included refusing to use computer-generated animation for the aircrafts themselves. Pirès had noted that Top Gun s 20-year old aerial sequences still had more impact than the CGI-based scenes of many recent movies. Thus, in Les Chevaliers du Ciel, the Mirages are always the real aircrafts. The approach led to the development of a brand new technology to capture the necessary footage.
Requirements of the system comprised being able to shoot steady footage in temperatures ranging from -45° Celsius to +50° Celsius and in extreme G-force conditions, including when the aircrafts broke the sound barrier. The film crew collaborated with Dassault Aviation, manufacturer of the Mirage aircrafts, to design and build a modified external fuel tank that was capable of holding five cameras aimed at different directions. The cameras were controlled by aerial footage director Eric Magnan from the co-pilot seat of the Mirage. Using video monitors to review the shots in progress, Magnan could ask each pilot to modify his position as to obtain the best possible footage. Each shot had been prepared in rough storyboard form and extensively analyzed during briefings with the pilots. Needless to say, the movie couldnt have existed without complete cooperation from the French Air Force. Obtaining technical support and clearances was not a problem though, as the military had seen what Top Gun had done for the U.S. Air Force!
The footage captured by Magnan came out looking more spectacular than Pirès had hoped. However, extensive digital work was necessitated in order to intercut shots of varying nature and to create scenes that could not be possibly photographed live. To this purpose, Pirès turned to visual effects powerhouse La Maison, Paris, where two of his frequent collaborators, visual effects producer Annie Dautane and visual effects supervisor Eve Ramboz, oversaw the project. We produced about 700 shots representing some 50 minutes of screen footage, recounts Dautane. It makes it the largest photoreal visual effects movie ever realized in France We did very little previsualization as the crew never knew exactly the kind of aerial footage they would be able to capture on any given day. It all depended on the weather conditions and on the maneuvers that the pilots would eventually be able to execute. As a consequence, the visual aspect of the shots was really defined in post-production. In this regard, we produced more than 1,500 temp shots at video resolution. It allowed us to nail down the composition of each shot before starting any high-resolution work. It also allowed film editor Véronique Lange to cut the sequences early and to be very precise in terms of the shots that were needed.
Solving Reflections Issues
A major part of the visual effects workload included the many scenes featuring the pilots in their cockpit. There was no way this could be shot with the principals in a Mirage. For this type of shots, special effects coordinator George Demetrau built a giant gimbal that supported the cockpit, part of the canopy, a green backing, the camera and the lights. By mounting all these elements on one single rig, Demetrau made it possible to shoot the actors in every possible angle with the greenscreen always remaining in the background.
For La Maison, the first step was to select the aerial plate that would serve as the background of any given shot, a daunting task in itself given the amount of footage that had been captured. The greenscreen plate was then shot with a camera angle and a lighting that matched the background plate. After that, the 3D department, under Luc Froehlichers supervision, used SOFTIMAGE|XSI to generate the portions of the aircraft that needed to be seen through the canopy behind the pilot. The elements were then rendered in mental ray.
Although appearing on screen as a mere prop, the visor of the pilots helmet required a considerable amount of work. La Maison had two options to shoot the actors in their cockpit: use a helmet without a visor and add it in CG, or use a complete helmet and paint out unwanted reflections on the visor. We chose to use the second technique, which meant that we had a massive amount of retouching to do, as some of these visors reflected the stage environment at 180°! Ramboz recalls. You could see the crew, the camera, the lights, etc. Once we had a clean visor, we needed to add the proper reflections in, which was quite a complicated endeavor in itself. We started from the background plate. The first step was to flop it, as any image should be in a mirror. Then, we synchronized this element with the background plate, so that any action occurring in front of the pilot would first be visible as a reflection on the visor, and then as the real thing in the background. After that, we modeled a CG visor that was tracked and match-moved to the real visor using 3D Equalizer. The reflection was then projected onto this CG visor as to acquire the proper curvature.
At this stage, the cockpit shots were not completed yet, as La Maison still needed to add the many readouts of the Mirage, both in the cockpit and as reflections on the visor. The plates had been shot with green monitors in the cockpit, Dautane explains. We generated the animation of all the readouts, using real data provided by the military and Gérard Pirès. Most of the people wont realize it, but those readouts provide the correct information a Mirage would give under the same flight conditions. Once the animation had been approved, it was integrated in the cockpit monitors. We also projected it as a flopped element onto the CG visor where it was combined with reflections of the environment. We then focused on the partial canopy that had been used on the cockpit during stage work. The missing parts were created in CG, composited in the plate, and mapped with the proper reflections. Final touches included adding reflections on the shiniest parts of the helmet itself. Once completed, the multiple layers were finally composited in Inferno, with Bruno Maillard, François Dumoulin and Ramboz overseeing the effort.
The Effect is Not Always Where it Seems to Be
The other key aspect of the movies visual effects was restoring continuity in the aerial sequences. The air-to-air footage had been shot in very different weather conditions, which translated into plates that seldom matched in terms of light ambiance and cloud formations. La Maison used Combustion to rotoscope the jet fighters and replaced the background with a brand new sky. The shots were then carefully graded to present a consistent look. The same technique was used on many other shots, this time for dramatic or aesthetic purposes. We often repositioned the Mirages in the frame, either to bring them closer to one another to add tension to the scene, or simply to achieve a nicer composition, Dautane notes. Sometimes, just by changing the position of one aircraft, the whole shot looked more dynamic.
One of the most impressive sequences of the movie features a Mirage evading radars by flying right below under a much larger Airbus commercial airplane. Amazingly, the stunt was shot live, Ramboz marvels. The Mirage pilot was really able to bring his aircraft right between the wings of the A-340! The shot does feature a major visual effect, though, but it is not where you think it is The Airbus that we shot was actually bearing the markings of another airline. Long after the shot had been photographed, Qatar Airlines became a partner of the movie and we were asked to replace the original markings with the colors and logo of the new company. We did that by modeling a CG Airbus that was tracked to the real airplane. We then projected the proper markings onto the CG body and superimposed the resulting image on the real Airbus body.
Pyrotechnic effects involving the Mirages were also created with a maximum of real photographic elements. For a shot featuring the explosion of a jet fighter, George Demetrau blew up a decommissioned Mirage that was hung from a crane high above the ground. The explosion was extracted from the plate and composited over a real Mirage in flight. Separately photographed debris and fire elements were added in to complete the illusion. A similar technique was used for a scene in which an eject seat is activated. The heart of the action was shot in front of a greenscreen with a mock-up seat and pilot. The element was then combined with a real Mirage in flight. Once again, extra layers included debris, fire elements, glass shards, etc.
A Thrilling Experience
Although the movie mainly required heavy compositing work, La Maison still produced tricky 3D animation for scenes involving flares, turbulences and the breaking of the sound barrier, a shot for which the CG department developed a specific fluid simulation program. After three months of preparation and five months of production, the facility delivered its final shot. It had scanned 150,000 original frames, produced more than 400,000 frames of effects shots including the intermediate steps and recorded some 100,000 final composite frames. The volume of this project was so huge that we had to re-organize our structure, Dautane concludes. This said, we still managed to produce these 700 shots with a staff of 20 only For us, there will definitely be a before and an after Les Chevaliers du Ciel And now, we know just about everything on flying state-of-the-art jet fighters! At least, in theory
Alain Bielik is the founder and special effects editor of renowned effects magazine S.F.X, published in France since 1991. He also contributes to various French publications and occasionally to Cinéfex. He recently organized a major special effects exhibition at the Musée International de la Miniature in Lyon, France.