Issue: Volume: 24 Issue: 9 (September 2001)

Freeze Frame




Artists turn a television commercial into a chilling experience

By Audrey Doyle

To demonstrate the fresh taste of Dentyne Ice chewing gum for a recent 30-second television commercial, director Steve Horn "froze" an intimate moment between a young couple at an elegant billiards parlor. The result is impressive, thanks to digital effects created by AFCG and Black Logic, both of New York.

The "Pool Hall" spot begins with a young man attempting a shot as a beautiful young woman captures his attention from across the room. She approaches, popping a piece of Dentyne Ice into her mouth, and kisses him, at which point the room is instantly enveloped in an icy sheen. The spot ends as two frozen billiard balls collide, and one of them shatters into thousands of pieces.

The main 3D effects in "Pool Hall" are the ice and the exploding billiard ball, which were difficult to create because of their unrealistic nature. Yet the real challenge was getting everyone to agree on what those effects should look like, notes Floyd Gillis, president of AFCG. To help nail down the appearance of the ice, Gillis and AFCG animator Steve Burger created a selection of ice surfaces-clear, foggy, cracked, thin, thick-in Side Effects's Houdini, running on SGI workstations. From those options, the production team chose a shiny, cracked, semi-transparent ice surface that would reflect the billiard balls and other areas within the scene.
In Houdini, the artists added ice effects to objects within the film footage, such as the billiard table.




One effect that didn't require a lot of discussion was the shattering ball, which was done before AFCG was awarded the job. "We did a sample animation in Houdini of the two pool balls hitting each other and one of them breaking apart," Gillis recalls. The previsualization helped Gillis and Burger determine the mechanics and look of the shot early, and as a result, they spent less time creating the effect in postproduction.

The spot intercuts live footage of the main billiard table and balls with CG replicas. So during the live-action shoot, Gillis and Burger supervised the effects shots to ensure that their digital elements matched the live footage perfectly. "We collected camera data and set measurements," Gillis says. "We even put reflective and diffuse spheres, like shiny Christmas tree ornaments, on the pool table and took pictures of them, since they reflected the whole environment and showed us where all the lights were in the scene."

Gillis then re-created the billiard table and several balls in Houdini, using the pictures of the reflective and diffuse spheres as a reference for lighting the CG elements. "We could see where the main light source was coming from and the objects that had to be reflected back into the iced-over pool table," he explains. "It gave us a nearly 360-degree view of the lighting setup," he explains.

The group then added the ice effects to objects in the film footage, including the balls, billiard table, cue stick, and overhead lights. The icing effect, which was applied to both CG elements and set pieces, was created and initially composited in Houdini, with final compositing in Discreet's Inferno.

The exploding billiard ball, meanwhile, is a particle system created in Houdini, with each particle representing a differently sized individual chunk of the ball. "We basically disassembled the CG pool ball into pieces, with a particle assigned to each piece," Gillis says. "I also created thousands of little ice particles, so when the ball breaks apart, all these ice particles go flying, almost like ice dust." In total, Gillis created 10 different particle systems, some resembling ice and others resembling the ball, and animated them so that as the ball explodes, pieces of the ice and the ball hit other balls on the billiard table, and they move in reaction to the force. Using Inferno, the team then composited the CG explosion onto the iced-over CG pool table.
Artists created a frosty atmosphere for a Dentyne Ice commercial, including this shattering billiard ball, created with a particle system in Houdini.




The artists also composited the actors into the final footage for the climactic scene at the end of the spot. "We shot the couple in front of bluescreen so I could use Inferno to change the environment from a warm to a cool palette as it ices over," says Patrick Ferguson, Black Logic designer/visual-effects artist. To complete the flash-frozen effect, Ferguson used Inferno to manipulate and composite a variety of practical effects, including mist, smoke, and breath elements, into the scene. Final rendering of the digital elements was done in Houdini running on a Linux renderfarm, while final rendering of the composite was done in Inferno.

"It was hard work, but I am happy with results," Gillis says. "Thanks to careful planning, the ice and explosion look realistic, and everything fits seamlessly with the live action."




Key Tool: Houdini, Side Effects (www.sidefx.com)

Audrey Doyle, a contributing editor to Computer Graphics World, is a freelance writer and editor based in Boston. She can be reached at audreyd@mediaone.net.
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