Issue: Volume: 23 Issue: 7 (July 2000)

Hoop Dreams: This 3D digital beast's got game




By Karen Moltenbrey

The prehistoric predator from the Jurassic past is back, and he's bigger and "badder" than ever. Instead of hunting human prey in a theme park, this new breed of velociraptor searches for its victims on a basketball court. Although ferocious and cunning, the beast meets its match when it takes on the NBA's Vince Carter, star guard/forward of the Toronto Raptors basketball team, in a television commercial shoot out for Gatorade, proving that it's not just Carter who's got game.

Duly named "Raptor vs. Raptor," the 30-second spot features a frightfully realistic 3D model of a raptor seamlessly composited into live-action footage of a hard-playing Carter. "The raptor contains an incredible amount of detail, and once it's composited into the background plate, the result appears to be an actual dinosaur playing basketball," says Nigel Sumner, one of the spot's technical directors at In dus trial Light & Magic Commercial Pro duc tions in San Rafael, California.

Both years of training and talent helped prepare Car ter for his en counter with the carnivore, but getting the digital raptor game-ready in just six weeks also took some doing. As signed to this task was modeler/animator Ismail (Izzy) Acar, who had previously en countered raptors and other dinosaurs while working as an effects animator on ILM's 1997 feature film The Lost World: Jurassic Park. In fact, Acar evolved one of the raptor models from the movie into a stronger, smart er, faster, fiercer, and more realistic beast for its commercial appearance.
In a fast-paced television commercial for Gatorade, ILM artists composited an animated digital raptor with the live action of an actual Raptor, Vince Carter of the NBA Toronto Raptors.




The raptor model, created in Cari, ILM's proprietary modeling software, needed extensive detail and an overall change in its proportions, particularly in the head and neck regions. To create realistic textures, the group used ILM's proprietary soft ware running on SGI (Mountain View, CA) work stations. "We knew how the raptor was supposed to look, based on what we had done for the movie, but the technology is advancing so quickly that we completely redeveloped that look based on what we can do now," Acar says.

Some of the more extensive changes were made to the model's bone and muscle structures. The bone setup ILM built a couple of years ago was a bit restricting, notes Acar. "In principle, you might think that the animation setup would be the same, but the experience we gained over the years and the latest developments in our proprietary software tools gave us a flexibility that wasn't possible just a couple of years ago," he says.
To make the action appear more compelling, the director used quick shots (a third of a second each) rather than long shots focused squarely on the digital raptor, which helped the CG models blend seamlessly into the live action.




Refining the muscle structure, however, required more research. Prior to using digital technology, Acar studied books on hu man figures, to get a sense of how to draw human muscles. He then utilized those concepts when creating the raptor's muscle struc ture. "There are lots of books that focus on dinosaur bones, so you already have the bone structure, but now you have to think about how the muscles would wrap around the bones in certain areas [of the body], and implement that into the modeling process," he says. "And, the raptor had to be more muscular in some areas of his body and more bony in others."

Once the artist defined the muscle structure digitally, "we had to find a way to move those muscles-they had to jitter and stretch," Acar notes. This was accomplished through both simulation and dependency on the bone structure. "We can define [the muscle structure using proprietary software] by how far we rotate the bones; the more they are rotated, the more the muscles come out. But in some in stances, we just have to animate it by hand," he explains.
Creating this new and improved raptor required the ILM animators to refine the bone and muscle structures of their model using a variety of proprietary software. Making the dinosaur sweat required some R&D, but the desired look was finally achieved with M




Prior to animating the raptor in ILM's Cari, Acar and the rest of the team studied basketball game tapes as a reference for simulating realistic action on the court. The group also reviewed nature films of crocodiles and large birds, particularly the ostrich, because they wanted to simulate the way that creature shifts its weight and rolls its feet while running.

"But before you start animating, you need to really get into the character and analyze how it would behave during a performance," says Acar. "In Lost World, the creatures behaved very animal-like, but in this spot, the raptor is very human-like in his actions. Not only is he cool, calculating, aggressive, forceful, and merciless, but he can also think."

That persona is clearly evident in the spot, thanks to director Steve Beck's decision to use quick shots (about a third of a second) of the raptor during game play. Had the shots been longer-say, two to three seconds each-the raptor may have looked somewhat awkward playing ag gressive one on one with a live-action Carter.

"The quickness of the shots [19 in all] made the piece look more powerful and the animation more realistic," explains Acar. "Usually in film and commercials, the concept is centered around the visual effects, but here the CG is introduced in a fast-paced way. Even though we worked for weeks on a shot, you only see it for a third of a second. It hurt us [modelers and animators] to see that, but the results were worth it."

The commercial also put ILM's research and development with fluid dynamics simulation to the test. To make the creature appear more realistic-in this case, to have it build up a gradual sweat-the artists used Alias|Wavefront's (Toronto) Maya Dynamics and proprietary software for rendering. "I don't believe raptors have sweat glands, so we used Vince Carter as a reference, giving the raptor the same amount of perspiration in each shot as Carter had," says TD Nigel Sumner. "Maintaining continuity throughout the 19 shots was extremely important."

The most intensive R&D, through, was put into achieving a realistic interaction between the raptor and the computer-generated liquid in the shot where the dinosaur bites through the Gatorade bottle. "We wanted the CG liquid to realistically interact with the raptor, spilling over it, and we just couldn't have achieved that with practical elements," Sumner says. For this fluid simulation, the animators used a proprietary software program.
In this shot, the artists used slow-motion animation to give the digital dinosaur its Michael Jordan-esque moves on the basketball court.




While preproduction was well under way, a crew filmed the live-action footage of Carter competing against a human raptor stand-in, to ensure that his actions and reactions were appropriate. During production, the body double was digitally erased using Softimage's Matador (Avid Technology; Montreal) and Photoshop (Adobe Systems; San Jose, CA) painting programs, along with some compositing techniques, and replaced with the 3D dinosaur. "At first, we thought we could also leave the ball in the shot and just animate the raptor to the ball. But that wouldn't work because of the size and type of motion we wanted to use," says Acar. "So we added and animated a CG basketball, too."

Compositing the live action and CG proved especially challenging, says Sumner, because of the sharpness (high resolution) of the background plates. "The director wanted a clean, crisp look for the piece," he says. This meant that the artists could not "cheat" by softening the digital imagery so that it blended more easily into the live action. "There was no room for forgiveness, so we had to be right on with the detail," he says.

Although the commercial can hardly be compared to a feature film, according to Sumner,"it's one of the most dynamic and energetic commercial spots we've done so far." Adds Acar: "The only difference between this spot and a movie was scale."

Key Tool Maya Dynamics, Alias| Wavefront (www.aw.sgi.com)
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