Jun 9, 2008

Speed Racer's Breakthrough CGI Road Rally: Anatomy of a Scene




They call it "car-fu." To brothers Andy and Larry Wachowski, high-speed chases are more about green screens than mean machines, more bumper car than NASCAR—if bumper cars travelled at 400 mph and came loaded with weapons, that is. In their long-awaited, live-action adaptation of Speed Racer—opening today on the big screen and the even bigger screens of IMAX—drivers ram each other's rides repeatedly, push competitors over cliffs and load up everything from spearhooks to beehives across the most breathtaking digital race tracks this side of the DiRT gaming franchise.

Foremost among them is the Casa Cristo 5000 road rally, the Google Earth-mapped deathtrap throughout which Speed (Emile Hirsch) sets out to avenge his brother's fatal accident—defying physics with 180-degree turns against saw-equipped drivers in the desert, ice-packed tunnels in the mountains, and Technicolor distractions in the city. "There were a lot of gadgets and unapproved weapons within the race," visual effects supervisor Dan Glass tells PM. "Early on, the directors had figured that Casa Cristo was going to be dirty." Two years, 250 full-time geeks, 500 digital shots, 100 terabytes of total film and one breakthrough style of moviemaking later, the best action sequence we've seen all year is kicking off a big summer for sci-fi—and maybe a new generation in special effects. Here's how it went from rig to race.


The Background
+ Click to enlarge

(Image courtesy Warner Bros.) After scouting exotic locations more suited to the likes of Lucas and Lutz than Neo and anime, three small visual F/X crews spread out last spring from Morocco to Death Valley for a level of robotic point-and-shoot surpassed only by The Matrix. Glass estimates that they snapped 10 million photos using the ultrahigh-resolution Canon EOS 5D digital camera—though not all were taken by hand. "The teams had some systems for animating the process," he says. "The cameras were placed on an automatic tripod that would rotate, tilt and capture the whole sphere." When photography wrapped in September, VFX artists stitched together some 10,000 shots—at 60 images per build—to mod the Wachowskis' latest claim to the digital Hollywood hall of fame: bubble photography—the 360-degree panoramic backgrounds officially known as QuickTime Virtual Reality; spheres that they matched up with actors' movements during filming before digitally re-renders in post-production.


The Terrain
Early in the planning process, Google Earth helped Glass and his team conceptualize Casa Cristo's intercontinental rocky road—through Morocco, up the African coast, over a bridge (which didn't make the cut) into the Italian Alps and, eventually, to Berlin. That digital road map was combined with the VFX crews' various on-site visits for a geographical mash-up: Castle-laden Morocco, lit by a Hawaiian sunrise, serves as a model for the race's tire-squealing urban start; pix from Death Valley and sand dunes from Namibia make up the desert shots pictured above; the mountains are a mixture of the Alps and Himalayas. Even the brick-like textures of Casa Cristo's icy mountain tunnels (inset), with headlights reflecting off slick walls for a pulsating CGI glow, came from actual tunnels in the Alps. "We had a lot of fun with optics," Glass says. "Completely cheating sometimes, but making stuff that looked fun."


The Cars
The production team designed more than 100 T180s, then modeled and painted them in a digital environment. At least two cars made the jump from digital to physical: Full-size replicas of Speed's Mach 5 and Racer X's Shooting Star (sans powertrains) were constructed to film certain scenes, and actors sat in full-size replica cockpits—complete with steering wheels, gas and brake pedals and back-lit instrument panels. To accurately simulate the movements of each digital vehicle—Speed Racer, after all, was filmed entirely against a green screen—cockpits moved along a hydraulic gimbal platform linked by racing software to sequences conceived in the pre-visualization stage. An encoder camera then allowed the Wachowskis to layer images of a car's exterior over actors in the cockpits to line up shots. Key moments, like a mid-air punch, were hand-animated. "Given a path through space, it would try to work out what the suspension of the car was doing," Glass says. "We wanted it to feel almost believable, but defying physics in quite a few instances."
By Erin McCarthy

No comments:

Post a Comment