Digital vfx allowed director Tim Burton to create a unique universe for Charlie and the Chocolate Factory. The Oompa-Lompas take the visitors on a wild ride on the Chocolate River. All photos courtesy of Warner Bros. Pictures.

Tim Burton’s fondness for practical effects is notorious. On all his movies, he has favored prosthetic make-up, miniatures or stop motion puppets to carry his vision, turning to digital tools only when no other option was available. When he set out to adapt Charlie and the Chocolate Factory for the big screen, he hoped that this approach would — again — suit the project. Roald Dahl’s beloved children’s story tells the tale of a young boy who wins a contest to visit, with four other children, the mysterious chocolate factory of Willy Wonka (Johnny Depp). The plant turns out to be a maze of magical rooms and machines manned by amazing little people, the Oompa-Lompas.

Although the fantasy world of Willy Wonka was ideally suited for Burton’s unique visual style, it required the creation of a universe far more complex than any practical effects could achieve. “When we started on the project, we estimated the visual effects shots count at 300 or 400, but it ultimately grew to 800, the majority of which were created by The Moving Picture Co. (MPC),” notes overall visual effects supervisor Nick Davis (Harry Potter 1, Troy). “It grew enormously, and one of the reasons was that Tim was initially a bit hesitant about using too many digital effects. He wanted to do as much as possible in camera and use CGI only when absolutely necessary. For example, one of the most ambitious sequences in the movie involved dozens of squirrels performing very complex actions. We had three options to create them: train real animals, build animatronics or use CG animation. We hoped that we could solely rely on the first two options to create most of the shots, but the movements that the script called for turned out to be too extreme to be accomplished in-camera. In the end, Framestore CFC produced more than 70 shots of very complex CG animation, with Jon Thum supervising the effort. It was extremely difficult, as some CG squirrels ended up full screen!”

Burton and the vfx team were hoping that real and animatronic squirrels could solely be used for this sequence, but in the end it proved too difficult. Framestore CFC produced more than 70 shots of very complex CG animation.

Another example of a sequence outgrowing the initial plan was the Oompas’ dance numbers. The little people are all played by one actor, four-foot tall Deep Roy. Originally, Davis intended to shoot Roy with a motion control camera and combine many passes to create a crowd of Oompas. But this approach met with unexpected difficulties. “Every plate with Deep had to be scaled up by a factor of about 1.7 to reduce him down to two-and-a-half feet, the size of an Oompa. That meant that if the camera traveled, say, 20 feet in three seconds on the set, it had to cover 35 feet in the same amount of time when we shot Deep! There was only one motion control rig in England — the Cyclops — that was able to accomplish this feat. Even then, there were shots for which it was just impossible. When the camera had to go from four feet up to 18 feet on the set, it meant that the Deep Roy plates had to be shot by a motion control camera that could go up to 30 feet — and there is no such rig… So, the only way to integrate the Oompas in those big sweeping camera moves was to turn to CGI. Plus, at two-and-a-half feet tall, an Oompa doesn’t fill a lot of space on screen. We realized that in order to compose interesting shots, we needed many more Oompas than first planned, which meant even more CGI! That’s how what was intended to be mostly a compositing job grew into an enormous CG animation project, with motion capture, facial capture, crowd, cloth and hair simulation…”

Multiplying Oompas
The Oompas shots were awarded to MPC, where more than 550 shots were created, including the Chocolate Room sequence, Violet’s transformation and several flashback sequences. Three different techniques were actually used to create the Oompas. The first one was filming animatronics scale replicas of Roy built by Neal Scanlan (Babe) for long shots of the characters sitting in a chair or in the boat. The second technique involved shooting Roy on greenscreen or bluescreen (depending on the color of his costume) and compositing him in the background plate. “There was one dance number for which we had to create more than 50 Oompas,” MPC’s visual effects supervisor Chas Jarrett (Troy) recalls. “We first imported the motion control camera move from the previsualisation. Then, we shot about 55 different passes on the real set with Deep changing position every time and repeating his dance routine with slight variations. For each pass, we needed between 10 and 15 takes, which meant that we ended up shooting 700 or 800 takes altogether. It went on for months!” The various elements were later combined in Shake.