CANNES -- When Steven Spielberg was deciding whether to make "War of the Worlds," he not only lined up Tom Cruise, but he called Industrial Light + Magic to check whether Dennis Muren, who first worked for him 20 years ago on "Close Encounters of the Third Kind," was available. He was.

George Lucas, on the other hand, doesn't ever have to check Muren's availability. That's because Muren works for him. Lucas will be recognized Sunday here in Cannes, where he is to be feted with the Trophy of the 58th Festival de Cannes and treated to a career tribute film assembled by festival head Gilles Jacob. The day will culminate with the world premiere of "Star Wars: Episode III -- Revenge of the Sith," which then opens next week in most territories worldwide.

There is sure to be much talk of Lucas' contributions to the cinema -- both good (his reinvention of mythic archetypes under the guise of sci-fi) and bad (his success led Hollywood to its current obsession with chasing blockbusters). But arguably, Lucas' most lasting contribution is the generation of visual effects masters, who redefined special effects in the process of solving the challenges Lucas set them.

Call it the ILM Revolution.

If Lucas sometimes seems a bit of a Yoda, then his VFX crew became a legion of Jedi masters who went forth to show other filmmakers how to unleash the force of their imaginations.

Muren, along with the other VFX wizards from ILM, combines computer science and software creation with aesthetic grace to show us things that no one has ever seen before. With each new movie, these pioneers reinvent the cinema before our eyes. For almost 30 years, ILM's FX masters have dominated the Oscar visual effects derby, racking up 14 wins. And when their rivals grab Oscars, chances are good that their skills also were forged in the ILM crucible.

Take this year's winner, John Dykstra of "Spider-Man 2." He started out at ILM in 1976, when it was created to make "Star Wars." In fact, without Dykstra, Ken Ralston ("Forrest Gump," "The Polar Express") and Richard Edlund ("Episodes IV," "V" and "VI," "Raiders of the Lost Ark"), the original "Star Wars" might never have been made.

It was nip and tuck back then. Lucas literally didn't know how he was going to pull off "Star Wars" on time and on budget. Stanley Kubrick's "2001: A Space Odyssey" had taken five years to make, but Lucas set out to pull off 360 ambitious effects in fewer than two years. It was Muren, Dykstra, Ralston and Edlund who figured out how to save valuable production time with their daring computer-synchronized, motion-control, blue-screen photography. They weren't sure it would work, but they had no choice. They pulled off the movie. And changed movie history.

Since "Star Wars," they've gone on to realize the visions of the cinema's greatest filmmakers, from Spielberg and Robert Zemeckis to James Cameron and Wolfgang Petersen. ILM took E.T. across the moon on a bicycle; created the exploding Star Destroyer in "The Empire Strikes Back"; the saucer pulling up clouds at the end of "Cocoon"; the go-motion rig for "Dragonslayer" that took the blur out of stop-motion; the first photorealistic CG character, the knight in 1985's "Young Sherlock Holmes"; the first morphing old woman in "Willow"; and the CG water alien in 1989's "The Abyss."

When Muren moved ILM into digital compositing, that made possible the back-to-back, mind-boggling effects in 1991's "Terminator 2: Judgment Day," 1992's "Death Becomes Her" (the first movie to achieve realistic human skin) and the CG dinosaurs in 1993's "Jurassic Park." Their pioneering effects on "Abyss," "Jurassic Park" and "Terminator 2" represented significant steps in the digital revolution -- and convinced Lucas that he could return to the Force and finally make "Episodes I," "II" and "III."

In the decades after the first "Star Wars," the wow factor has come to dominate Hollywood movies. The top 20 blockbusters of all time are either visual effects spectaculars or CG animation. In the past decade, studio budgets for visual effects have skyrocketed from an average of $5 million to $50 million per film, and the percentage of movies that are dominated by effects has shot up as well. "Movies of size and scope, marquee blockbusters, are sold by their trailers," says Scott Ross, chairman of Santa Monica effects house Digital Domain ("Titanic," "I, Robot"), who launched his career at ILM. A single shot -- whether it's the 250-foot tower of water in "The Perfect Storm" or Kate and Leo on the bow of "Titanic" -- can sell a blockbuster.

"A-list visual effects guys are make or break for a big effects movie," says Lorenzo Di Bonaventura, who supervised Warner Bros. Pictures' "Perfect Storm." Hiring a visual effects supervisor is like casting a star, says Hutch Parker, head of TCF at 20th Century Fox. "Your choice of who to play the role is essential."

Under mounting pressure to deliver eye-popping visuals, studios and directors chase after the top FX stars. Sony relied on Sony Pictures Imageworks' Dykstra for the first two "Spider-Man" movies. Zemeckis collaborates exclusively with SPI's Ralston, who has won four Oscars for their films together. This year, the duo's drive to use new Imagemotion technology yielded the $175 million "Polar Express," which was slammed by some critics but still delivered enough wow to gross $281 million worldwide. For "Lemony Snicket's A Series of Unfortunate Events," director Brad Silberling leaned on ILM's Stefen Fangmeier, who trained for years with Muren.

Truth is, three worlds -- live action, CG and animation -- are now collapsing into one. In live action, the old-school photographic techniques pioneered by ILM are swiftly being replaced by computer graphics. The younger generation is more comfortable with the digital virtual world. One gets the sense that such directors as Lucas, Peter Jackson, Kerry Conran and Robert Rodriguez would like nothing better than to replace the real (including actors) with elements that they can control completely. Such movies as "Sky Captain and the World of Tomorrow," "Sin City" and "Constantine" are moving toward less on-location reality and more mind-numbing hordes of "smart" cyber-extras and stunt doubles. And such FX artists as Muren, Fangmeier, Dykstra and Ralston, using similar CG animation to what Pixar Animation Studios employs, are figuring out how to replace actors with living, breathing, talking digital humans. It's their Holy Grail. "You can't find anything harder," Ralston says. "We are absolutely familiar with every frigging subtlety in the human body. Millions of things are going on when we speak that we'll never be able to do."

Even the hotshots at SPI and ILM stand in awe of New Zealand's Oscar-winning Weta Digital, which created Gollum from "The Lord of the Rings." The question is, who will meet the Weta challenge? Will it be Jackson's remake of "King Kong," coming in December? Or will it be Cameron, who is ramping up his first film in six years, the 3-D, high-def, sci-fi adventure "Battle Angel"? Odds are good that when Cameron makes the call on who will make real his celluloid fantasies, it will be one of the ILM FX masters.

Anne Thompson can be reached at athompson@hollywoodreporter.com.