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'Asterix at the Olympic Games': A New French VFX Record

Asterix marks the biggest vfx achievement in France, and Alain Bielik has the scoop from Duboi, BUF Compagnie and Mikros Image.

Duboi oversaw Asterix at the Olympic Games. All images © 2007 Les Editions Albert Rene/Goscinny -- Uderzo. © 2007 Pathe Renn Prod./La Petite Reine/Tri Pictures Constantin Film/Sorolla Films/Novo RPI/TF1 Films Prod. 

Ever since his creation in 1959 by writer Rene Goscinny and illustrator Albert Uderzo, Asterix the Gaul has remained the most beloved comic book character in France. In the rest of Europe, his popularity is only challenged by Tintin's. Set in 52 BC, the 33 albums tell the Gaul's adventures in many situations and countries. In one of his journeys, the brave hero becomes an unlikely competitor in the Olympic Games. This time, though, he cannot use the magic potion that gives him superhuman strength in his other adventures. No performance-enhancing drugs allowed, even in 52 BC!

Asterix at the Olympic Games is the third live-action movie based on the comic book character. The previous two movies had made extensive use of digital visual effects, but the new production necessitated more vfx shots than both films combined. In fact, the movie ended up shattering every record in France with about 1,400 shots.

When Producer/Director Thomas Langmann and Director Frederic Forestier embarked on the project, they enlisted Visual Effects Supervisor Alain Carsoux and French vfx powerhouse Duboi to oversee the project. The company had already provided visual effects for the previous two productions. "Initially, the vfx shot count was much lower and Duboi was the sole vendor," Carsoux says. "We started with extensive previsualization of the action sequences. We especially focused on the chariot race, as it was the most ambitious sequence in the entire movie. While we were working on those shots, the script was being rewritten, and, with each new rewrite, the vfx shot count dramatically increased..."

When the shot count reached heights that were unheard of in French movie history, production decided that it would be wiser to spread the visual effects among several vendors. VFX Supervisor Christian Guillon of L'EST was brought in to oversee the effort and to award sequences. Three vendors ended up sharing the workload:

Duboi did most of the set extensions and establishing shots, and also produced many individual vfx. Total: 530 shots.

BUF Compagnie created the Olympic Stadium for the Games sequences, and the digital extras populating it, as well as an extravagant dream sequence that later formed the basis for the trailer. Total: 515 shots.

Mikros Image was asked to produce all the stunts- and Games-related vfx. Total: 315 shots.

Establishing a World

Duboi's primary mission was to establish the action from a geographical point of view: Caesar's Palace (in Rome, not in Las Vegas... ), Olympia's harbor, the Palace of King Samagas of Greece, Asterix's village... Duboi also had to create a great deal of totally independent visual effects such as the trademark fistfights with the Romans, a character becoming invisible, a Druid whose body is spectacularly stretched to no harm, the effect of the Magic Potion on a horse, etc. "This meant that we had a tremendous amount of set-ups," Carsoux notes. "We could almost never re-use elements from any given shot. Since all our shots were different, we had to start from scratch every time, which required an enormous effort in design, R&D, modeling, texturing and lighting."

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BUF Compagnie created the most spectacular set extension ever attempted in a French feature film. The Olympic Games take place in a stadium that was built as a partial set and almost every shot in the sequence required work.

Duboi's tour de force was a 40-second shot in which the camera flies above the sea, arrives at Olympia, goes up the hills, reaches the stadium and finally reveals Samagas' palace -- all in one continuous take. "Production wanted to shoot a helicopter plate to create the shot around, but I kept fighting for a full CG approach," Carsoux explains. "I didn't think we could ever find a location that matched what the directors had in mind. In the end, the final composite features only 5% of live-action footage -- the rest is computer-generated. Using Maya, we modeled Olympia and the harbor itself with all the ships. The sails were animated in nCloth. The town geometry, without any ship or extra, comprised of over 50 million polygons... The city was then populated with extras generated in Massive. For the sea, we used a simulation generated in a proprietary fluid engine. Samagas' palace was a detailed model that was built based on blueprints provided by the art department. Rendering was tackled in RenderMan, with mental ray being used for specific elements. The final composite comprises of 271 layers, all assembled in our proprietary 2D package Dutruc. This shot was almost a year in the making."

Most of Duboi's establishing shots were a combination of two different techniques: fully detailed geometries for the foreground, and 2½D projections on lower resolution geometries for the background.

For the fistfights, Carsoux's team recreated the signature effects that Duboi had designed for the first live-action movie. The Gaul performer would be shot on set or on location hitting imaginary Roman. Then, on a bluescreen stage, a stuntman would perform the action of being hit by a massive blow. Duboi would then extend his movement upward in 2D before combining the two plates.

Book Your Digital Seat

BUF Compagnie also had its hands full with set extensions. In fact, Pierre BUFfin's studio had to create the most spectacular set extension ever attempted in a French feature film. The Olympic Games take place in a stadium that was built in Spain as a partial set by Production Designer Aline Bonetto. Just about every shot in the extensive sequence required BUF's intervention, as the stadium was almost always visible in the background.

"Using proprietary software, we first modeled the arena based on the construction blueprints," says Visual Effects Supervisor Stephane Naze. "Then, we went to Spain to take measurements of the actual set, and modified the digital model accordingly. We also took still photographs of the set at different times of the day, with bracketed exposures, which provided us with a great variety of textures for mapping. It allowed us to re-light the 3D stadium as to perfectly match the live-action plate. We also shot many stills of individual elements -- columns, staircases, seats, etc. -- that we later used as texture maps on the corresponding 3D geometries." The surrounding town and hills were created as detailed 3D models and 2½D projections.

For the arena, BUF took photographs of the set at different times of the day, which provided a great variety of textures for mapping. The town and hills were created as detailed 3D models and 2D projections. 

The team also had to develop the digital extras -- tens of thousands of them. During principal photography, production used a group of about 120 costumed extras to be seated in the background for some shots that wouldn't require visual effects. BUF's team took those extras to a tent that had been set up on the lot. There, the performers were photographed from varying angles, wearing different costumes, as to provide as many unique characters as possible. The team was then able to use those images to generate corresponding 3D costumes that could be colored or textures in any given way.

"We built 20 different body geometries that formed the basis for our characters," Naze explains. "We then altered each one of them in height, width and skin tone to create an infinity of variations. Parallel to our photo shoot with the extras, we also captured them performing 15 typical actions of a patron in a stadium: seating, standing, cheering, etc. It was not your typical motion capture set up, with tracking markers and special cameras all around. We utilized our proprietary Video Motion Capture system, which consists of a group of video cameras that shoot the performer -- in his regular costume -- from several angles. Using this footage as a reference, our animators hand-animated all the main actions. Pierre BUFfin is a strong believer of keyframe animation, as opposed to traditional motion capture. He really trusts the animators to create a true performance. Later on, these animation cycles could be accelerated or slowed down, giving us endless possibilities to play with. We then used a script to automatically place the extras in the stadium. They were positioned randomly within predetermined zones based on patrons' nationality. For each sequence, the directors would give us a nationalities ratio for the spectators: 20% Gauls, 30% Romans, 10% Goths, etc."

The stadium set extensions turned out to be a huge endeavor, but BUF had another major challenge to tackle with the so-called "Brutus' dream" sequence in which Caesar's son sees himself as the commander of an impossibly large army. "We had to deliver the shots very early for the trailer," Naze comments. "For Alexander's main battle scene, we had created about 3,500 digital characters. This time, we had to generate more than 100,000 Roman legioneers! The directors wanted the whole plain to be covered with Romans up to the horizon. Once again, we used our video motion capture system to gather reference footage that was translated into key-framed animation cycles. Those cycles were then run in our proprietary crowd simulation package to create the legioneers' animation. Since Alexander and Arthur and the Minimoys, we have kept improving our approach for rendering crowd scenes. Our system allows us to adapt the resolution of any given element in the frame depending on its distance to camera, which greatly optimizes render time." Completed long before the film's release, the impressive trailer made a huge impact on audiences and helped establish the unique scope of the production.

Game Over

Meanwhile, artists at Mikros Image were busy crafting character-related visual effects. Digital doubles were required for many action shots involving characters being ejected from chariots, thrown in the air, crash-landing, etc. Some of them necessitated a very precise animation as the directors wanted both a cartoony effect -- to match the comic book illustrations -- and a realistic action - to match the rest of the movie... Tricky proposition indeed!

Mikros Image created the digital doubles required for many action shots involving characters being thrown in the air, ejected from chariots, crash-landing, etc. Some work had to match the comic book illustrations. 

A majority of the Game shots required the cooperation of two vendors: BUF would create the stadium and the spectators, and Mikros Image (or even Duboi) would generate the foreground action. "Usually, the final composite was created by the vendor who was tackling the foreground layers," notes Mikros' Visual Effects Supervisor Hugues Namur. "Our main mission was to create scenes that could not be performed by a real human being. For instance, there is a scene where a Roman athlete grabs his opponent by the ankle and crushes him on the ground. During plate photography, the actor was only holding a fake leg with a sandbag attached to it to generate realistic interaction with the ground. Our 3D team, lead by Nicholas Rey, replaced the prop with a fully-animated CG character whose leg was precisely tracked to the practical leg. Particle animation was used to create additional sand projections."

A key part of Mikros' assignment was to create traditional 2D composites. Due to scheduling conflicts or weather conditions, some of the actors couldn't be filmed on location and had to be shot separately on a bluescreen stage. Several key chariot race shots were also captured on bluescreen: the principals first performed cable-assisted stunts on a static chariot. Then, the footage was combined with live-action plates shot at full speed on the actual racetrack -- but only after BUF had added the stadium in.

Mikros Image produced its shots using Maya for 3D, proprietary Arnold for rendering and After Effects and Nuke for compositing.

Animators had a lot of fun with a sequence in which coleopters are used by Greek judges as antidoping test agents. "The insects were modeled and animated in 3D, based on practical props provided by production," Namur explains. "We had a huge rotoscoping job to perform when the directors requested the addition of 3D legs to a coleopter that a character was biting. The shot was never meant to be a vfx shot and had been filmed with a static prop. But later on, it appeared that the insect should logically move when bitten. So, we had to paint out the original legs, which took a tremendous amount of work since the background was made of moving Romans with their long, flowing togas..."

A key part of Mikros' assignment was to create traditional 2D composites. Due to scheduling conflicts or weather conditions, some of the actors had to be shot separately on a bluescreen stage. 

Like Duboi and BUF, Mikros also tackled a massive set extension with the Palester complex, the training site for the athletes. Once again, artists could use a partial live-action set as a basis for the full digital construction. "We first tracked the plates, and used a low-resolution model of the Palester to block the shots," Namur comments. "Once everything was in place and approved, we started working on the high resolution version. Depending on the distance to camera and the camera movement, we would use either a 3D geometry or a matte painting. When the nearby Samagas' palace was featured in the frame, Duboi would provide us with the geometry and textures to include it in the shot."

After two years of work, including a year of actual production, artists at Duboi, BUF Compagnie and Mikros Image learned a great deal on this historic vfx-intensive French film. For the first time, competing houses learned not only to share a project, but also to share shots, which they had never done before: a successful experience that could mark the beginning of a new era.

Alain Bielik is the founder and editor of renowned effects magazine S.F.X, published in France since 1991. He also contributes to various French publications, both print and online, and occasionally to Cinefex. In 2004, he organized a major special effects exhibition at the Musee International de la Miniature in Lyon, France.

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