Crash Course
Issue: Volume: 32 Issue: 5 (May 2009)

Crash Course

VFX Artists 'Survive' a Harrowing Crash-Landing Sequence

Those who are familiar with the television series Lost know that nothing is at all what it seems on the mysterious tropical island that has become a home of sorts for the survivors of Oceanic Flight 815.

 The fifth season, which began this past January, finds the remaining survivors as they time-travel on the island, shifting between the present and the past after one of them “moves” the island in an attempt to save it and its inhabitants. The other survivors who escaped the island last season now are attempting to return to save those they had left behind. This reunion begins to unfold in the highly charged episode “Namaste,” as the rescued survivors find themselves on another doomed aircraft—some by happenstance, others with the intent of finding their former friends. And indeed, the plane crash-lands on the “other island,” bringing them home, only during a different time period.

For the Lost episode "Namaste," Eden FX created this CG plane landing within a totally synthetic environment.

Despite the realism of the crash scenes, nearly everything in them, aside from a cockpit set, is computer-generated—from the entire exterior of the plane, to the establishing shots of the island below, to the jungle as the 737 lands and skids out of control. And while the character’s feat of moving the island proved monumental in terms of story line, just as momentous was the creation of the island for “Namaste,” not only in terms of plot, but also computer graphics.

“For this episode, we have a sequence showing the landing of a 737 airplane on one of our islands, an event that had been foreshadowed in several earlier episodes. This was a scene we knew would be a challenge but turned out to be a much bigger challenge than we had originally imagined,” says Mitch Suskin, Lost’s visual effects supervisor. “Here we had a plane landing on a small island—the viewers needed to know the island was small but would still be able to accommodate the landing of a 737.”

Even though the series is filmed in Hawaii, there was no way to shoot a small island, such as the one depicted in Lost, with aerial photography since it was unlikely the production crew could have found an actual locale that would have met the requirements of the story line in the episode, Suskin notes. So, the VFX supervisor approached Eden FX—which produces the show’s digital effects, including Dharma stations, the island’s Smoke Monster, matte paintings, water, and so forth—asking the studio to build the island in 3D, not only for an establishing shot, but also in fine detail for the rough landing.

“We wanted to ‘fly’ the 737 over [the island] at low altitude and have it appear as real as possible,” Suskin says. “The plane lands on a dirt runway on the island, but the runway is too short for a 737, so the plane ultimately crashes through the jungle.”

Adding to the difficulty of this sequence was the time crunch: Eden only had a little more than two weeks to complete the work. “When I first proposed this scene to Eden, I thought they were going to laugh at me,” says Suskin. The Eden group admits there were a few chuckles, but there was also fierce determination to make this scene a reality, at least on screen.

Hard Landing

According to John Gross, Eden FX cofounder and in-house VFX supervisor, the group—comprising three CG artists and two compositors—created slightly less than two minutes of animation for the sequence, which involved both interior and exterior shots of the plane. “They wanted something big, beautiful, and glorious for when the characters return to the island. They wanted something really dramatic,” he explains. “As we started working out the animatics, we got more and more the picture they wanted—a very dangerous ride along the island. We tried to make it more perilous.”

The adventure starts with an outside shot of the plane. For this, the group was able to save time by reusing a model they had built for an earlier episode. The plane, which had been modeled in NewTek’s LightWave and textured in Adobe’s Photo­shop, was animated in LightWave for this new scene.

Later, the digital 737 is shown flying over the island, which is a completely synthetic environment. Most of the point-of-view shots of the airplane’s flight over the island and its landing and crashing through the jungle were from three camera locations: within the cockpit with the pilot and copilot, on the wing of the plane, and from the underbelly of the plane. The group used one additional POV placed on the island itself as the plane roars down the dirt and sand runway in what the Eden artists called “the glory shot.” According to Ross, Eden avoided using any camera angles that would have been impossible to achieve in real life, so the sequence would not appear fake.

“Mitch [Suskin] and Eric Hance, Eden’s digital supervisor, sat down early on and tried to work out the animation to make the crash as perilous as possible,” says Gross. “They started out with the plane coming up against one section of mountains and then going around them. That evolved into this idea of basically having a canyon run where they careen past a set of mountains and as they are trying to dodge those, there is another. It was amazing to see how the animatic process allowed the excitement to grow.”

The group spent approximately three to four days creating and revising the animatic, done in LightWave. In the end, the animatic contained about 10,000 frames of animation. “One of the great things about the pipeline we set up for this project was that it allowed Stephan [Bredereck, the lead artist] to use the animated cameras and objects while he was working on different parts of the island,” says Hance. “For the most part, we didn’t have to reproduce or re-create things from one package to the next.”

It’s a Jungle

The highlight of the sequence, without question, is when the plane careens through the jungle after running out of space on the dirt runway. Some shots in the crash sequence were filmed with a practical cockpit set surrounded by greenscreen. Outside the cockpit windows, the Entity FX team composited CG scenes of the island and jungle.

“One of the biggest challenges was how to build the island to the level of detail needed in such a short time frame,” notes Suskin. “This really was a scene with feature-film aspirations that had to fit within the budget and tight schedule of a TV show.”

To accomplish this, the group used a combination of commercial and in-house software. The terrain modeling was done in Autodesk’s Mudbox, while the vegetation—comprising approximately one million high-resolution trees, palm trees, and plants—was crafted mainly in LightWave and textured in Photoshop. Several layers of vegetation, added in compositing using Eyeon’s Digital Fusion, established the actual look and photorealism.

The plane's landing is shown from a number of POVs, though the artists using any camera angles that would have been impossible to achieve in real life.

While the island is only about eight miles long, in CG terms it is much larger. “We estimated the polygon count of the CG island environment at over 62 billion,” Bredereck points out.

To render such an enormous environment required the creation of proprietary software. Adapting a volumetric and instancing system the artists had previously used for bees, flies, and character work, the group was able to adapt the tool to make multiple copies of objects (in this case, the vegetation) without eating up a lot of memory. Each plant is computed once, though there may be 100,000 copies of it in the scene. “Without the code, it would have been impossible to render that many plants,” adds Bredereck. The group also used the instancing plug-in to populate the digital landing strip with grass clumps, dirt particles, and sand.

Additionally, Eden used its proprietary rendering-control software, Red Five, and  proprietary layer management software, R2D2, to organize the multiple render layers, such as specular, ambient occlusion, and diffuse buffers.

“These trees don’t really have polygons when they are instanced and rendered, so they don’t have real motion vectors. We had to come up with a script to get the post-process motion-blur going,” notes Bredereck.

Furthermore, the island comprises very high resolution displacement maps and normal maps, and to create the UV coding for those maps, the Entity team used Luxology’s Modo.

Planning was another key to accomplishing this task. “We knew at some point we would have to pull the trigger on renders that reached from 100 to 500 minutes per frame, so we had to carefully manage our time to avoid having to re-render during the last few days before the show aired,” says Hance. One way the group stayed ahead of the curve was by rendering the information with the highest dynamic range possible the first go-around.

“That was challenging in the beginning but saved us in the end,” Hance adds. “We could change just about any tree in compositing and all the shadows; the different aspects of the scene could be changed in comp without re-rendering. That really helped us do the entire production in the short time frame we had.”

On the backside, Eden had 130 nodes processing the information. The machines were dual quad-core systems running Windows. Prior to this job, the group had a base network of machines with 4 gigs of RAM but had to increase that to 8 gigs.

So, what exactly sold the scene? According to Gross, the CG had to look natural and real. “You couldn’t have that one moment of getting pulled out to reveal the big effect,” he says. “Sometimes you show off too much, but here, our work was part of the show. [The CG] felt nicely integrated and woven into the shots.”

When asked what their initial reaction was when Suskin first approached them with his concept, Gross, Hance, and Bredereck all broke out in a laugh, as they had done with Suskin, though this time the chuckling reflected their pride in a job well executed.

“They really did want something cool for this big return to the area, and our first response was, ‘Okay, a full digital island, I think we can do that.’ Then there was a big interval of, ‘Wow, this is a huge undertaking,’” says Hance. Bredereck had similar feelings, realizing that a natural landscape means infinite detail. So for him, he felt a mixture of shock and challenge.

“In the 11 years I have worked in this business, this was definitely one of my most challenging assignments due to the scene’s content and the time frame we had to work within,” Bredereck says.

Chances are good, though, that there will be more Lost challenges to come, as the producers and directors undoubtedly will continue to shock the audience with twisting and turning stories before the series ends next year.

Karen Moltenbrey is the chief editor for Computer Graphics World.