[Dream World]
Issue: Volume: 27 Issue: 10 (October 2004)

[Dream World]

It all started with a dream: Amid the flurry of a snowstorm, the outline of a behemoth zeppelin becomes more defined as it floats into view and eventually docks atop a statuesque structure of concrete and steel. Moments later, a vintage P-40 Warhawk piloted by a revered flying ace rips through a stylized 1930s New York City skyline, cutting down giant marauding robots as they wreak havoc on the city.

This was Kerry Conran's dream, and one that the digital artist had relived day and night for nearly a decade. Finally, it has become a reality, now that his retro/futuristic story of Sky Captain and the World of Tomorrow has landed in theaters. Told through unconventional filmmaking, the movie follows Sky Captain (Jude Law) and his ex-girlfriend, reporter Polly Perkins (Gwyneth Paltrow), as they search for clues to the robotic madness and attempt to solve the mysterious disappearance of scientists from around the world.

A trailblazing project, the live-action film has no real sets, landscapes, or locations. Instead, the entire movie was filmed against bluescreen, with teams of CG artists generating all the sets and nearly all the props, except those with which the actors physically interact. Yet every scene is brimming with detail, as some of the backgrounds were crafted from period photos and film footage augmented with CGI, while others were crafted entirely by digital methods. With this type of composition, the group was facing 2000 effects shots; 1100 of which were completed by World of Tomorrow, an effects studio formed for this project only. The remainder, under the direction of senior visual effects supervisor Scott Anderson, were outsourced to several effects houses after Paramount signed on and set a release date for the film.
A landmark in filmmaking, the live-action feature Sky Captain and the World of Tomorrow contains all-digital sets and backgrounds created with a wide range of imagery, from period photographs to high-end 3D graphics.

"The notion that the technology was finally evolving to the point that you could break down live action [into layers] the same way that animation had been done for years meant an explosion of choices, possibilities, and opportunities for filmmakers," says Conran. Yet for Sky Captain, going digital was far more than a technical feat; it was the only way Conran could achieve the desired style for the movie: a period look with a sci-fi bent.

More than six years in the making, this ambitious film is the first full-length feature by writer/director/artist Conran, who spent four of those years creating a six-minute short that provided a glimpse of his dream. Using the short—which merged classic styles and iconic images with cutting-edge digital technology—he was able to capture the hearts and support of prominent industry players. These included producer Jon Avnet and A-list actors Law, Paltrow, and Angelina Jolie in the lead roles.

Realizing that without help his vision would never materialize, Conran used the short to recruit other heavyweights, including Darin Hollings. Excited by what he saw, Hollings signed on as visual effects supervisor and assembled a team of 100 artists who comprised World of Tomorrow. "Many people were getting onboard for all the right reasons, because they loved the project," says Hollings. "But with every shot a composite, we knew that to do it as an independent project would require unconventional methods."

By factoring in a number of what-ifs from the realms of science fiction, fantasy, and history, Conran crafted an all-digital world for the film, unlike anything seen before. And yet, somehow, it appears familiar by reflecting cinematic film classics, Republic Pictures serials (1930s film chapterplays, or cliff-hangers), and comic-book superhero flicks through the use of stylized realism.

With no template for making a movie like this, the group had to forge solutions as it went along. Yet, because the actors could devote only five weeks to principal photography, there was no time to allow for mistakes. This situation prompted Conran, Hollings, and the rest of the crew to assemble a unique previsualization and preproduction plan that contained a comprehensive 3D animatic, created in Alias's Maya, which included every detail in the film, whether it was real or virtual, including the camera specs.

"We were going to have to do a shot every 12 minutes—or 40 shots a day—in order to finish the filming on time," says Hollings. "Each shot had to be planned in advance. We had to know exactly where the camera and the actors would be in one shot as well as the next." Therefore, before the shoot, the filmmakers conducted a full technical run-through of the film with friends substituting for the actors, a process that enabled them to uncover and fix a number of unforeseen problems, including mismatched lens information between the virtual Maya cameras and the Sony high-def video cameras.
Conran had planned for the film to be black and white, in keeping with its period noir style. To avoid a potential risk at the box office, however, he opted for a unique stylized look instead. This was achieved with a contrast and diffusion system whereby

Then, at Elstree Studios in London, where the live action was filmed, the team replicated every detail from the practice shoot. Employing location grids for its virtual stages and the actual three bluescreen stages, the group planned the subsequent day's filming in exhaustive detail, including the choreography of the actors and the cameras, distances, tracking issues, lighting, the camera rigs, and even the costumes. Additionally, the group superimposed the grids onto the animatic to make sure the imagery was properly aligned, while the actors reviewed the animatic before each take so they'd have an idea of their on-screen surroundings amid the sea of bluescreen.

With its all-virtual sets, the movie takes viewers around the world and then some, from the frosty Himalayan Alps to the brilliant Technicolor valley of Shangri-la. For years, Conran had amassed volumes of reference books, photographs, actual period and stock film footage, and other images to use for creating these locations. Initially, the group had planned to use actual archived imagery for nearly 70 percent of the backgrounds, and 3D for the rest; however, when the film was completed, those figures were nearly reversed. At times only portions of the period file photos and footage were used; other times additional types of imagery were layered and integrated, including recent photos.

The majority of the scenes, especially those of New York City, were modeled in Maya and rendered with Pixar's RenderMan, while the animation was keyframed in Maya. For the explosive elements, the team used a combination of Maya rigid-body dynamics and pyrotechnics footage filmed by Hollings and his colleagues. "We had our core CG software, but if you name any piece of software for creating visual effects, we used it," notes Hollings. "We had an eclectic group of artists who worked on this, and we didn't have time to hold them back from using a certain tool."

In the end, the artists had expanded nearly every 3D set to the point where each scene contained 50 to 60 layers on average, including the background plates, stock footage, archived footage, digital mattes, live-action explosions, and CG elements, composited together in Adobe's After Effects, and edited with Apple's Final Cut Pro. To manage all the assets, the group initially used Nexsan Technologies' Ataboy storage drives with a capacity of about 10tb. But when Paramount came aboard, the studio expanded its setup to 30tb with a Network Appliance (NetApp) storage device.

"This movie is not so much about the technology we were using to put it together, because we were using off-the-shelf tools," says Hollings. "Rather, it was about the style and the look of the finished product, and why we were using visual effects. We wanted to make a piece of art."

Even though the film is being hailed for its technical achievement, what lies beneath is great filmmaking, realized through the composition of the shots and the use of lighting and framing. The entire movie was shot in 24p HD, which is less expensive and more flexible to use than film, and faster to use on set. Yet, unlike most other movies shot in high def, Sky Captain forgoes the format's crispness and instead uses a soft focus, subtle modulations of light and dark, and the textured look of film rather than video to help integrate the live action and CGI.

As a matter of fact, the group's intention to maintain a film noir look for the project led to a major obstacle: Traditionally, these types of environments are formed by shadows, and in this film, there were no environments to project the shadows. So the team had to rely on creativity and digital techniques, such as adding low lights, backlights, and sidelights on set to produce illumination contrasts. Later, the artists carried this theme over to the digital side by setting up lighting rigs that provided a similar dramatic effect.

"Unlike traditional visual effects in which the CG elements are lit to match the live-action plate, little or none of the live-action plate's lighting influenced the CG lighting," says Michael Sean Foley, lighting director. "Instead, we lit the virtual sets as if we were lighting a real set, by making a light rig that would work for the widest shot of a sequence, and later adding more lights for the tighter shots. Then, we'd bring in all the cameras for that sequence and render a frame for each shot with that one rig."

According to Foley, this process took one person nearly a week to do 20 to 30 shots. After the lighting rig was correct, however, the group rendered the whole sequence at once. If two sequences had similar lighting, the team recycled the rigs, sometimes flipping the key light or adjusting the fill ratios. "We addressed each sequence as a whole, but handcrafted each shot as if it were a still photo," he explains. "This enabled us to complete over 900 shots and still maintain a unique style throughout the film."
While trying to solve the film's mounting mysteries, reporter Polly Perkins (Gwyneth Paltrow) and Sky Captain (Jude Law) travel to various locales, including this all-digital exotic jungle realm.

Conran had planned to extend the darker period style by creating the entire movie in black and white, but had decided against it because of the financial risk such a project posed at the box office. Instead, the group chose a washed-out foreboding look, with a digital twist. "We decided that if we were going to do color on this movie, we would do it in such a way that it added to the lure and didn't look like a colorized movie," says Hollings.

Therefore, to achieve the unusual period look for Sky Captain, the group set up a contrast and diffusion system whereby the color film ran through a filter that tinted the color images with black and white. The artists then composited the shots in black and white, focusing on composition, tone, and diffusion. After the shots were approved, the group reintroduced the color using the original colors from the film plate that were then washed over the entire black-and-white image. This process proved especially valuable because it helped smooth out the varying tones in the range of image types present in each scene.

"A lot of the film's magic comes from the compositing, and we used many After Effects filters and were creative with edge blurs, diffusion passes, and other passes that isolated certain values and either pulled them out or suppressed them," says Hollings.

Without question, Sky Captain's atypical style and story take viewers back in time to a place they are familiar with but have never seen before. Ironically, modern films don't embrace this genre, contends Conran, yet the older films, which might have, didn't have the capacity to pull something like this off. "We were finally able to realize what visionaries back then had imagined," he says, "but could never quite articulate, at least on film."

Karen Moltenbrey is a senior technical editor atComputer Graphics World.