In the first
Star Wars movie, a scene where a lightsaber was ignited needed to be achieved in a least two shots, because the lightsaber handle had to be replaced with another handle fitted with a solid "blade" covered with reflective tape. In
Empire and
Jedi, lightsabers being ignited would have their blades hand-drawn at the end of the handles, while in Episode I igniting lightsabers were given their blades through computer graphics. The same techniques were brought into play to "doctor" the fighting sequences, were the metal rods used in lieu of laser blades were optically or digitally replaced. The technique used to generate the glowing, diffused light of a lightsaber - and many other visual effects - is called rotoscoping. Rotoscoping has been used throughout the
Star Wars saga and is in fact one of the most essential tools at the disposal of the visual effects artists. Moving from the optical realm to the digital sphere, the art of rotoscoping is a perfect example of visual effects technology evolving as it should: right under the spectators' noses without them noticing any seam in the transition.
Visual effects artists use rotoscoping to track a visual element they need to modify, remove, or add to a sequence. Developed in 1915 by animation pioneer Max Fleischer, rotoscoping remained virtually unchanged for seventy-five years. Traditionally, visual effects artists would use the rotoscope, a high-perched camera/projector combination looking straight down at a flat work surface, to project scenes from a movie, frame by frame. On each frame, they would trace by hand the elements to be worked on, creating a series of cells used as guidelines to indicate where the special effects needed to go. For the lightsaber blades, for instance, rotoscoping experts traced the "stick" blade of each prop lightsaber, showing the animators exactly where the blue, red and green glows needed to be positioned. Once the blades had been created as separate elements, they would be optically added to the live-action images.
With the computer, things are different. Now rotoscoping is accomplished within the digital realm, and new tools have been developed to speed up the process. "Nowadays you can indicate to the computer that your elbow and arm are here," says Squires, "and that you want these two elements traced. Digital rotoscoping then allows you to tell the computer that ten frames later the elements are over there, and the computer will go ahead and generate everything in between the two positions." Once the guidelines have been established for each frame, computer animators step in and create the effects that will be later added to the original footage. Everything is now digital, but the technique remains surprisingly similar to what it has always been. And through better technology and special effects techniques stepping from the physical world into the virtual one, ILM strives to remain true to the classic look of the Star Wars saga. "For things like the lightsabers, we'll put in the glow and the shimmer, and when they cross we'll add a flash and all the other details that fans are used to," Squires says. "But no matter what the technology is or becomes, we'll always remain consistent within the Star Wars universe."
