James Cameron has spent the last few years working on underwater documentaries, but his last feature broke records that still stand, the blockbuster to end blockbusters: Titanic.

Now, Cameron is heading back to the multiplex with a new sci-fi adventure that, he hopes, might change the way movies are made. Science fiction is hardly a stretch for Cameron. Before making the most expensive Hallmark card of all time, he made movies like The Terminator, Terminator 2: Judgment Day, and The Abyss that defined the cutting edge of effects technology in their day. And now he's ready to try again.

The Terminator revolutionized robotics; T2 introduced the first CG main character, and broke ground in motion capture; even Titanic's effects were pioneering (remember all those CG bodies falling into the water?). This time the innovation is using a mix of live characters and environments and computer-generated characters and environments, all of them using digital 3D stereo.

Rather than just milking 3D for what he calls "gimmick shots" -- things flying out of the screen -- he'll be using it for dramatic moments too, relying on the idea that if the brain experiences something as it does in real life, one of the barriers between real and artificial experience will be done away with. I don't know if it'll work, but, read this in-depth interview with Variety, and you'll agree, he sure is convincing.

Even though the number of screens capable of playing 3D movies is still relatively small, directors like Jon Favreau, who has seen pieces of Avatar, are calling it the future. Cameron knows that there will be theaters that play it in 2D, and is designing the film to make sure it still works. And Avatar may be the kind of event picture that pushes more theaters to invest in the new technology, which would make more filmmakers consider it, which really would change the way movies are made, like Cameron hopes.

It can be dangerous, hinging a movie on its effects and hoping for greatness; look at Speed Racer, or Star Wars: Episode I. But when it works it can be a real leap forward, and Cameron seems to have his priorities right. In that Variety interview about his new 3D system he said, "... the fantasy experience is served best by a sense of detail and textural reality supporting the narrative moment by moment. The characters, the dialogue, the production design, photography and visual effects must all strive to give the illusion that what you're seeing is really happening, no matter how improbable the situation might be if you stopped to think about it..." The effects aren't the point of the movie, the narrative is; but without effects that support the illusion, the experience is broken.

The story, at least according to the rumors, follows a paralyzed former marine on a resource-rich planet who becomes an "avatar" by combining with one of the indigenous aliens. Forced to work as a miner, he ends up crossing over to fight alongside the aliens against the human invaders who are exploiting the planet. Part Spartacus, part Captain Planet, maybe a dash of Alien Nation? Could go either way. But Cameron's 3D gamble definitely seems worth a look. Maybe by the time Avatar's December 2009 release date rolls around, you'll even be able to find a theater that can play it.