LOS ANGELES ? Win or lose at the Oscars this weekend, "Avatar" is already assured of its place in Hollywood history, a 3-D milestone to rank alongside the arrival of sound in the 1920s or color in the 1930s.

Director James Cameron's science-fiction blockbuster has already redefined the art of special effects on its way to becoming the highest-grossing film of all time, raking in more than two billion dollars worldwide since its release.

James Cameron had to wait more than a decade for technology to catch up with his imagination, but when it did the results were spectacular, a visually stunning masterpiece which has been nominated for nine Academy Awards.

The American Film Institute has lauded "Avatar" as a "pioneering effort to unleash the human imagination... a film that has firmly established itself as a landmark in the way stories are told."

Set in the year 2154, "Avatar" tells the story of Jake Sully (Sam Worthington), a paraplegic former Marine who is sent to live among the Na'vi, a humanoid race of blue aliens living on the exotic Earth-like moon, Pandora.

When Sully falls in love with a Na'vi native he rebels against his human controllers, leading them in a rebellion to save their way of life.

The film's pro-environment, anti-imperialist storyline has attracted criticism from conservatives but Cameron remains unapologetic.

"It's not an Oliver Stone-style bludgeon-you-over-the-head political film but it does have a political subtext," said Cameron, who is nominated for best director 12 years after he won the award for "Titanic."

Cameron was able to bring the world of Pandora and the Na'vi to life courtesy of experimental, state-of-the-art, "performance capture" cameras which the film-maker had helped to invent.

Working under blanket secrecy out of a giant converted warehouse in the Los Angeles suburb of Playa Vista, the cast of "Avatar" were rigged in bodysuits covered with small sensors, allowing 140 cameras to capture every movement.

Additionally, a tiny camera fixed to each actor's head allowed Cameron to record every muscle movement or expression in their faces. That information was then passed to animators who helped transform actors into Na'vi.

After this painstaking process was complete, animators then examined video of the actors in each scene to ensure that their Na'vi doubles accurately reflected every nuance of their performance.

Cameron barely took a day off for five years after production on his masterpiece got underway.

"It turned out to be more labor-intensive than expected," Cameron has said. "I took a day off about once every seven weeks, when I started slurring my words. I got the swine flu ? I took half day off for that."

Cameron's reputation for attention to detail is reflected in the research which went into creating the world of Pandora and the Na'vi.

University of Southern California linguistics expert Paul Frommer was hired to invent an entire language, a process which took months just to settle on rules for a basic grammatical structure.

"He didn't just tell me to build a language from scratch. He actually wanted to discuss points of grammar," said Frommer, who drafted an instruction manual ? "Speak Na'vi" ? used to teach actors.

Meanwhile every animal on Pandora were given Na'vi, Latin and common names, while an expert in botany from the University of California was hired to provide detailed scientific descriptions of plants created in the film.

Other experts hired for the film included an astrophysicist, a music professor, and an archaeologist.

Finally a team of writers and editors helped distill all this information ? most of which is never mentioned in the film ? into a 350-page manual dubbed the Pandorapedia, explaining the culture and science of the planet.