August 21st is "Avatar" Day!

SAN DIEGO - James Cameron originally wrote "Avatar" as a way to challenge the special-effects firm Digital Domain, where he served as chief executive. But it took technology 14 years to catch up with his vision of a faraway planet populated by otherwordly plants and animals where humans embody avatars just to brave the landscape.

"In the same way that I wrote 'Terminator' just to get a directing gig, I decided to write a story that was full of creatures and characters that would push the art of CG for that company," he said. But after artists there said it couldn't be done, Cameron shelved the idea.

Ten years later, when he realized technology had caught up with his cinematic visions, he dusted off the concept and helped develop technology to make it work. On Thursday, he presented world-premiere footage of his progress to more than 6,000 fans at Comic Con.

The "Titanic" director showed more than 20 minutes of footage from the film.

"Avatar" introduces viewers to the planet of Pandora, where the lithe, blue, indigenous Navi people inhabit a lush and wondrous place dense with green forests, fluorescent pink flowers, bizarre hammerhead dinosaurs and flying dragons. Sam Worthington plays Jake Sully, a soldier on duty there, and Zoe Saldana plays Neytiri, the Navi princess who befriends him.

Saldana learned the fictional Navi language and studied with a dialect coach to perfect a Navi accent on her English.

"I'm from Queens," the actress said.

Sigourney Weaver, who plays botanist Grace Augustine, studied the fictional flora and fauna of Pandora to prepare for her role.

"Every single plant and creature has come out of this crazy person's head," she said, pointing to Cameron.

A longtime sci-fi fan who likens himself to the average Comic Con conventioneer, Cameron said "Avatar" is more than just a fantastic tale 14 years in the making.

"The technology could be made (for it) to happen, but also (it) was just wanting to do something, I don't want to say important," he told fans. "But something that has this spoonful of sugar of all the action and the adventure and all that, which thrills me anyway as a fan, but also wanting to do something that has a conscience, that maybe in the enjoying of it makes you think a little bit about the way you interact with nature and your fellow man."

It may seem like a simple story about "nasty" humans fighting with "those beautifully, spiritually evolved Navi," he said. "But it's really not, because we make science fiction as human beings for human consumption."

"It means the Navi represent something that is our higher selves, or our aspirational selves, what we would like to think we are or maybe what we realize we're losing," he said. "And the humans in the film, even though there are some good ones salted in, represent what we know to be the parts of ourselves that are trashing our world and maybe condemning ourselves to a grim future."

He announced that fans worldwide could see 15 minutes of the film for free on "Avatar Day," Aug. 21. The film is set to open Dec. 18. Comic Con continues at the San Diego Convention Center through Sunday.