by Ron Magid

When special-effects supervisor Joss Williams lobbied to create Charlie and the Chocolate Factory’s Chocolate River in camera, director Tim Burton gave just one caveat: “Make sure it looks edible.” Williams recalls, “Early on it was a tossup whether the Chocolate River would be digital or practical, and we felt CGI would be much more limiting on set, and more expensive. Tim wanted to do as much as possible in camera, so we did a number of small-scale tests to see if we could get the look right.”

After several weeks of testing different substances to give the river “that yummy look,” Williams found the perfect thickening agent: Natrusol. But getting the right consistency was less tricky than finding the right color. “We were going in the milk-chocolate direction,” he says. “We played around a lot to get the right color; it looked a bit gray to the eye, but on film, it looked fantastic. We made 1.25 million liters of it and used it all the way through the shoot. We planned on having it last eight to 10 weeks, but then the filmmakers decided to keep it for another four, which resulted in a smelly week or two! The chocolate waterfall was easier to keep good because we were pumping that around continuously.”

By making the Chocolate River practically, the filmmakers were able to expend visual-effects capital on various other aspects of Wonka’s Chocolate Factory. One of these was the Oompa Loompas, the strange tribe of small creatures who run Wonka’s phantasmagoria. Visual-effects supervisor Nick Davis tapped The Moving Picture Company (MPC) in London to create the creatures, which were all played by one actor, Deep Roy. However, Burton actually wanted the Oompa Loompas be considerably smaller than the diminutive Roy. “Deep is 4 feet, 2 inches high, and Tim wanted the Oompa Loompas to be 2 feet, 6 inches, so there was our immediate challenge: our star was more than one and a half feet too big,” says Davis.

The scale issue, as well as the seemingly endless replication of Roy, demanded a variety of approaches, including motion-control shots of Roy in different areas of oversized sets, bluescreen shots for which the actor was composited into conventional-scale or digital environments, and fully CG shots of Oompa Loompas that were created via motion capture and/or hand animation. “We had to figure out whether to shoot plates on set, build overscale sets or create virtual sets,” says Davis. “In the end, we mixed all three.”

Adding to the challenge was the fact that the Oompa Loompas had to sing and dance. “We asked to see Danny Elfman’s songs as soon as possible,” recalls Davis. “Meanwhile, we’d discuss possible blocking for the numbers with Tim and the choreographer. As soon as Tim approved a song, the choreographer would work out a routine with Roy, then we’d bring in a bunch of professional dancers, videotape them [going through the routine], and work with Tim to previsualize the entire sequence until we knew every single cut. That previz became a bible for each song — we didn’t deviate from it.

“Once we had the previz, we figured out how to best accomplish each shot,” Davis continues. “Whenever the Oompa Loompas were one fourth the size of the screen or smaller, we made them CG because that enabled us to do more dynamic camera moves. When we used motion control, we had to scale up any camera moves by a factor of 1.73.”

Because Burton was keen to use Roy instead of CGI whenever possible, “we actually spent six months with two units, one shooting plates and the other doing repeat motion-control passes on Roy against bluescreen,” says Davis. “The motion-control work was a huge undertaking — we did about 3,000 takes, often to music! These were often very complicated mo-co moves during complicated dance routines that sometimes required Deep to interact with himself. Deep’s lip sync had to be bang on, plus he had to exactly hit his mark. He put in some serious hours, that’s for sure!”

The results are thrilling, he adds. “MPC got it down to where the CG Oompa Loompas and the real ones look absolutely identical.”