BEAUTY'S ONLY SKIN DEEP.(Technology Information)

A rocker maintains his groove while stripping down to the bone

In the music video Rock DJ, when British pop singer Robbie Williams fails to attract the attention of aloof roller skating beauties and an attractive female disc jockey with his groovin' on the dance floor, he performs a dramatic disrobing. After shedding his clothes fails to impress the women, he reveals even more, eventually peeling away skin, flesh, and organs until his still-dancing digital skeleton finally catches the DJ's eyes.

To "pull off" the rocker's shocking striptease, animators could not miss a beat during the real Robbie's transition to a computer-generated model. "Our challenge was to create a seamless blend between the artist and his digital double, retaining his distinctive dance style accurately in the computer-animated content," says Damien Raymond-Barker, head of production at Clear, the London CGI house that created the digital dancer.

Achieving this delicate transition required the Clear artists to match a prosthetic suit, muscle for muscle, on their digital model. Then they applied motion-capture data of the singer from AudioMotion (Banbury, UK) to match, step for step, his unique style of dance.

Creating the Hollow Man-like effects required using a combination of actual and digital means, according to Raymond-Barker. This was because the tight-fitting rubber suit that Robbie donned under his clothes, which enabled him to appear to peel away huge chunks of flesh, already contained a fair amount of bulk. If a prosthetic bone layer were to have been added, Robbie, who is fairly muscular himself, "would have ended up looking like Arnold Schwarzenegger in the suit." To eliminate some bulk, a CG model was substituted for the prosthetics whenever bone was revealed through muscle tissue, which occurred during the last 30 seconds of the 4-minute video.

To create the 3D skeleton encased in muscle, the animators purchased and modified a Viewpoint polygonal model of a human body's muscle structure rather than work from a cyber scan of the rock star, which Raymond-Barker says would have been more time-consuming. Using Side Effects Software's Houdini because of its "fast modeling abilities," the group traced each element of the Viewpoint model to create a NURBS surface before converting the file into an IGES format for export into Softimage.

The modelers then scaled the face and body elements in Softimage to match Robbie's exact proportions, using photographs and measurements of the singer for reference. "Getting the model to look like Robbie was difficult because there was no skin or hair to work with," says Raymond-Barker. "All the giveaway details were gone, so we had to ensure that his eye sockets, the nose region, the formation of his teeth, and other areas of his head and face matched his physical dimensions perfectly."