Beyond Belief

The Curse of Clarity Returns!

Effects technology has made countless strides since Star Wars launched the revolution in 1977. Still, one of the major reasons fanciful creatures and objects look better in today's productions is that effects artists have largely solved the problem of injecting suitable blur into their work. In this column, we'll see how.

For Star Wars, effects supervisor John Dykstra developed the first practical motion-control camera system for dynamic photography of spaceship models. Highly repeatable stepper motors drove a camera boom that swept over almost-stationary models. Multiple passes of the same shot could be made in perfect alignment: one to capture the model itself, one for its on-board lighting, one to obtain a perfect silhouette for later use in "matting" the model into a background image, and so on. With early motion- control systems, a two-second model ship fly-by might take hours to shoot. Camera speed was slowed down proportionately; for each frame, the shutter might open for several minutes while the camera crept past the model. During each frame the camera moved approximately as far relative to the model as it would have in a "real" shot. Near-perfect blur was automatic. The result was a more realistic impression of fast and violent motion than had ever been achieved before on the screen. In Spielberg's Close Encounters of the Third Kind (1977), effects designer Douglas Trumbull used similar technology to produce realistically-blurred multipass images of glowing UFOs.

By the time Spielberg made his ill-advised John Belushi comedy 1941 (1979), technicians at Industrial Light and Magic (the Marin County, California, effects factory that grew out of Star Wars) were experimenting with a technique called "go-motion." As the name implies, go-motion was a direct attempt to address the blur problems inherent in stop-motion photography of miniatures. Additional computer-controlled stepper motors were attached not to the motion control camera boom, but to the miniatures themselves. Instead of being posed by animators between frames and photographed at rest, go-motion miniatures would move, repeatably, at microscopic speed. In 1941 go-motion contributed to a few long shots of a Japanese submarine on the surface. Spielberg wanted to do camera moves over the sub and matte it into background imagery of the Pacific Ocean even though crewmen were visible on the sub's deck. This would have created an insuperable compositing challenge if go-motion had not made the little crewmen on the model sub move exactly the same way in pass after pass.

Go-motion came into its own in Spielberg's E.T., the Extra-Terrestrial (1982). Remember that film's signature image: E.T. and his young human friend crossing before the moon on a flying bicycle? Go-motion motors repeatably rotated the bike's spoked wheels, making possible complex composite shots where the smooth, realistic wheel movements "sold" the effect.

When ILM tackled Return of the Jedi (1983), the finale of the original Star Wars trilogy, go-motion technology wasn't ready for the challenges it posed. (Jedi featured scores of composite shots with bright backgrounds: forests, deserts, smoky rooms with lots of backlight-far harder to composite than shots with dark outer-space or night-sky backgrounds.) To produce the Rancor, a fifteen-foot lizardlike biped that menaced Luke Skywalker in Jabba the Hutt's lair, effects supervisor Dennis Muren rejected both stop-motion and go-motion. Instead, animators Phil Tippett and Tom St. Amand used puppetry and concealed rods and wires to manipulate the miniature Rancor, which was shot "live"-that is, actually moving-with slow-motion photography.

James Cameron's The Terminator (1984) was the last major film to offer an old-fashioned, jerky stop-motion character. The Terminator robot (supposedly Arnold Schwarzenegger's endoskeleton) was realized with life- sized puppets wherever possible. For certain long shots, there was no way to avoid stop-motion (and no money for go-motion). Animator Peter Kleinow used a Vaseline-smeared glass plate between the lens and the model to suggest blur, but it didn't work.

Back on the high-tech front, The Golden Child (1986) gave ILM a chance to try out a new real-time motion control recorder. For a sequence of Eddie Murphy battling a man-sized demon, director Michael Ritchie shot live-action footage of Murphy fighting a non-existent opponent. The camera moved freely; in some shots it was hand-held. Effects technicians used field recordings of all that movement to apply precisely matching moves to their go-motion footage of a miniature demon. The shots were amazingly good, especially considering that Ritchie jerked his live camera more enthusiastically than the ILM gang originally had in mind.

Robocop (1987) showed that a gifted animator could get good results even with plain old stop-motion. Shots of the ED-209 "enforcement droid" were done stop-motion in front of rear-projected backgrounds-just the way Ray Harryhausen did films like Jason and the Argonauts (1963), whose failings I discussed in my previous column. Tippett, by then Hollywood's master stop-motion artist, added convincing blur in a refreshingly low-tech way. While exposing each frame, "we introduced blurs basically just by wiggling the puppets," he told Cinefex. It was the last sustained used of stop- motion in a major Hollywood picture, and it worked remarkably well.

When Spielberg started planning Jurassic Park (1993), effects artists planned to execute long shots of the T-rex, velociraptor, and other dinosaurs using go-motion miniatures. Advances in computer graphic (CG) animation persuaded the makers to abandon go-motion in midstream. A huge ILM crew under supervisor Dennis Muren realized the full-body dinosaurs as perfectly- realized three-dimensional computer constructs. (Continuing the vocabulary of "stop-motion" and "go-motion," they called the new method "full- motion.")

Mathematically-exact blurs were incorporated right into the images as the computers rendered them; as every living human knows, the results were perfect. Phil Tippett had been hired to direct the go-motion work; instead he shared with the CG artists his deep understanding of how to make artificial creatures "perform," and helped develop a number of "waldoes" (wearable hand or body rigs that let animators feed motions to their computers in a more lifelike way than by typing start points and end points into a computer console).

Another ILM crew under supervisor Mark Dipp used Jurassic Park technology to create more fanciful CG dinosaurs for The Flintstones (1994). One "must-have" scene replicated the familiar cartoon gag in which Dino, Fred Flintstone's purple pet dinosaur, drags Barney (Rick Moranis) across Fred's living room at the end of his leash. The background shot was a blurry pan shot that followed Barney across the soundstage living-room set. For the computer, applying proper blur to Dino's movement plus matching the blurs introduced by the background camera's movement was a piece of cake; stills from this sequence are amazing in the realism and correctness of the blur they displayed.

Where do we go next? High-end CG imagery is migrating onto simpler and less costly computers. Instead of the high-end Silicon Graphics workstations used in Jurassic Park and The Flintstones, several shots of the Enterprise-D starship in Star Trek: Generations (1995) were created entirely as 3-D CG constructs. They were rendered, blur and all, on ordinary Apple Power Macintoshes using off-the-shelf software by ElectricImage, Inc. Rendering at motion-picture resolution took an average of just six minutes per frame.

Next time you go to the movies, don't expect jerky, failed stop-motion shots to tell you how the shots were done. Hollywood's effects artisans have long understood that convincing motion requires not only changes of position in successive frames, but appropriate blur as well. And the problems of creating it have been conclusively solved. Heck, by the time this column sees print you may be able to do it on your own desktop.

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