SAN DIEGO -- The buzz hasn't been all about money, as it was before "Titanic" launched a gazillion ticket sales. This time it's: Can James Cameron be the king of the film world again?

The writer-director re-enters the Hollywood scene with the 3-D technical marvel "Avatar," his first film since Oscar-winner "Titanic" became the top box-office movie of all time and he declared himself "the king of the world" as Best Director of 1997.

"I think ['Avatar'] is the kind of movie that changes the way movies are made," Sigourney Weaver told a small gathering of media members at Comic-Con International in July.

Weaver plays scientist Grace Augustine, head of the Avatar Program in which humans have their consciousness linked to an avatar, a biological body that can survive in the lethal air. With Cameron and co-stars Zoe Saldana and Stephen Lang, she had just faced an audience of thousands of sci-fi faithful, who reach back beyond "Titanic" to Cameron's "Terminator" films and "Aliens," which reinforced Weaver's status as a genre goddess.

"The profound thing to me about 3-D is how good regular scenes seem," said Weaver. "You just go, 'Oh yes, this feels right.' That I didn't expect. I expected it to feel odd or novel. It doesn't. It feels like this is the way it should be."

That's not to say that there's anything ordinary about "Avatar," an off-world romantic action-adventure with a message. It features alien creatures and exotic settings that reflect Cameron's years of underwater filmmaking.

The lovely Saldana is seen onscreen only as her computer-generated character Neytiri, a blue, pointy-eared, long-tailed native of the planet Pandora, where the environment supports teeming alien life and resources coveted by earthlings.

Lang, who plays Col. Quaritch, said, "It owes a tremendous amount to Edgar Rice Burroughs, for example; it's got that same sense of epic adventure of new worlds being discovered," while Saldana said it's really par for Cameron's cinematic course.

"It's no different than what he did with [the original] 'Terminator.' This was a film about the future, but the essential story is what happens when man gets ahead of himself, defies his mortality, and creates something so perfect it ends up coming back to haunt him. And 'Titanic' sort of had that same kind of essence. ... It's about what happens when we underappreciate what we have."

Cameron was having none of the comparisons, although he understands the impulse to do so.

"I think 'Titanic' and 'Avatar' are chalk and cheese ... they're just two totally different movies," he said. "I suppose you can compare their box-office performance. 'Titanic' was an anomaly in the sense that it somehow keyed in to global emotions in such a way that it made a ridiculous amount of money."

Those dollars allowed Cameron to abandon Hollywood and spend years earning the trust of the scientific community, eventually shooting deep-sea documentaries -- "Aliens of the Deep" among them -- while contributing to technology that allowed exploration of Earth's oceans as never before.

With that in mind, the "Avatar" story has taken a back seat to discussion of the look of the film, which uses that technology and is clearly influenced by the oceanographic years.

"To you, I disappeared," Cameron told the gathered media. "To me I didn't disappear. I was just doing [what] I really wanted to do. And I could afford to do it after 'Titanic.' I did six deep-ocean expeditions at that time, and it turns out in retrospect to look like a master plan, because ... we did a tremendous amount of 3-D shooting, some of it in very rough conditions. So in a funny way, when I started the live-action shoot on 'Avatar,' I knew what to do. In fact, it was almost easy by comparison."

Regaining his perch as a big fish in the Hollywood pond was always part of the plan. He had begun his own visual effects company back in the early 1990s, when he partnered with effects master Stan Winston, who was of a like mind to "do really cool stuff and use the new technology to create CG characters."

"True Lies," "Apollo 13" and "Titanic" followed, none with the immersive, 3-D experience of "Avatar," none that pushed the envelope for creature-character development that Cameron was craving.

He started writing "Avatar" right after "Titanic," but the timing wasn't right, he said.

"The idea was to create something that we couldn't develop at the moment it was written. But I screwed up. I didn't go one level out, I went four levels out, and my guys shouted me down. Whereas on 'The Abyss,' with the water-weenie [shape-shifter] character, we had gone one level out. Same thing in 'Terminator 2,' with the liquid dude. We could just barely do that or we could imagine doing it, so it's only a question of timing."

These days, when 3-D movies and screens to show them are multiplying at a furious rate, the time was right to harness that energy and make "Avatar" a reality.

As a first test, Cameron presented the Comic-Con audience with a 24-minute clip in the San Diego Convention Center's largest hall. It showed how humans, with focus on Sam Worthington as paralyzed Marine Jake Sully, are reborn as avatars that resemble the native Na'vi of Pandora and how he becomes transformed by the experience. And the scenes emphasized the way the 3-D experience brings moviegoers along for the ride, whether it's encountering dinosaur-like creatures in a dense forest or being saved by a blue beauty in a jungle inspired by coral reefs.

Before facing the geek hordes, Cameron told Weaver, "This is where it counts. These are the people who are going to notice every single thing," she said.

The sights were stunning, but there were few hints of the major conflict in "Avatar," and the Comic-Con audience did not see the scene that Cameron said was the biggest challenge of making the film.

"There was one scene that took us two years to figure out how to shoot," he said. "It's the action finale [that] involves characters at four different scales, and they're all interacting with each other, all played by live performers. It was crazy how hard it was. But at least we knew it was the finale of the film so it was worth our effort. And it's a corker."

Weaver had seen the completed film that same week and said it left her teary-eyed. She added that it was a 2-D version -- "I don't think I could have taken it in 3-D," she said of the action scenes.

Working with Cameron again was as easy as "putting on a pair of old slippers," Weaver said, although the process was new to her. The actors talked about how freeing it was, running around in black leotards with green dots on a mostly bare stage.

"There's a terrific irony in the whole process because with all the technology that's involved, working in a bare room, which is very much like a rehearsal room, it absolutely requires you to go back to the fundamentals of acting," Lang said. "It's almost a total exercise in imagination and flat-out pretend."

Weaver noted that if Cameron has changed in the years since "Aliens," "It's that he's a very fulfilled person." But as a filmmaker, some things never change.

"He drives everyone hard but no one as hard as himself. He operated on almost every shot. He invented the cameras. He invented the flora and fauna and the creatures. There's nothing this man didn't do ..."

"And he named every flower," Zaldana interjected.

Cameron has other film projects in the works, including remakes of "Forbidden Planet" and "Fantastic Voyage," but he said he could just as easily go back to the pace of making a big Hollywood movie and then making a bunch of documentaries before re-emerging as a player again.

For now, he said the experience of making "Avatar" has reinvigorated his love of moviemaking.

"Maybe it's my insecurity as a filmmaker that I want to have all this stuff to show people and dazzle them and all that. But it's good, it's a win-win deal. Because I get turned on by the challenge of that and the audience gets turned on by the result."

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