The director of "Titanic," "The Terminator" and the "Avatar" series, which used performance capture technology to help create fantasy characters in 3-D, has consistently raised the level of movie visual effects. But Oscar-winner James Cameron tells Jonath

Much of what we see from the Earth-like moon of Pandora, the fantastical setting for the "Avatar" franchise, comes from a soundstage in Los Angeles, where scenes from the second and third movies were filmed. "We had to build an ocean," director James Cameron said. "We could make a two-meter swell. We could make a wave crash up on a shoreline if we built the shoreline."

Sigourney Weaver, Zoe Saldaña and other actors shot their underwater scenes in the nearly 250,000-gallon tank. Digital artists then took those shots, called performance captures, as a template to render the final versions of the characters we see on screen.

"So, performance capture, we use a whole bunch of cameras to capture the body performance of the actor," Cameron explained. "And we use a single camera (or now we use actually two) to video their face. They`re in a close-up 100% of the time. But there`s a beautiful thing about being in a close-up 100% of the time. It`s very much like theater rehearsal."

Clockwise from top left: Oona Chaplin as Varang, Zoe Saldaña as Neytiri, and Stephen Lang as Quaritch, in James Cameron`s "Avatar: Fire and Ash." 20th Century Studios

"Avatar: Fire and Ash" is the third film in the series. It tells the story of the indigenous Na`vis` fight to defend their paradise from colonizing humans.

Cameron created these stories and this world. He`s always been a dreamer, even as a kid in rural Canada. "I lived in a world of my imagination - it was comic books, it was science fiction. I read a lot. There were movies, TV shows," he said. "I mean, I had a pretty fertile imagination."

Cameron moved to Los Angeles with his parents as a teen. He briefly attended community college, where studies included marine biology, before dropping out and picking up odd jobs, including truck driving.

So, how did he go from blue collar to Hollywood? "Watching `Star Wars,`" he said. "I used to put my headphones on and listen to fast electronic music and imagine space battles, hyperkinetic space battles with all kinds of maneuvers and energy weapons, and people going through debris fields and all that. If the things I`m seeing in my mind can be the same things that are in a movie that`s the number one movie in movie history, then I`ve got a salable imagination."

He returned to school, although not in an official capacity. "I started to study visual effects, and the way I did it was, I didn`t have the money to go to USC or anything like that. So what I used to do is, I`d go down to USC, I`d go bury myself on a Saturday, when I wasn`t driving a truck, in the stacks. And I`d read everything I could find on optical printing and front-screen projection and, you know, sodium process traveling mattes. All self-taught. I`d Xerox all these scholarly papers, put them all in binders. And I had this shelf full of black binders that had essentially a graduate course in visual effects and cinematography."

He found jobs in visual effects departments and production design, rising through the ranks quickly due to his technical knowledge.

Then, in the early 1980s, Cameron, inspired by a literal dream about a robot exoskeleton, co-wrote and directed "The Terminator." The movie put him on the map, and proved he could turn his imagination into reality.

But CGI wasn`t available at the time; the effects were done largely through puppeteering. "We just figured out how to do it all practically," Cameron said.

He showed us around his private museum in Los Angeles, full of movie props from his films, including "Aliens," where puppeteers brought Sigourney Weaver`s powerlifter - and the Alien Queen - to life. Of the Alien Queen, Cameron said, "Her head had, I think, seven or eight different axes of movement that were controlled by cables that went basically out her butt. And we had to hide all that stuff, so there was a lotta steam and smoke and backlight and things like that."

James Cameron shows correspondent Jonathan Vigliiotti puppetry used in "Aliens."/ CBS News

Cameron`s first use of CGI came with the science fiction movie "The Abyss," It was also his first cinematic foray into another one of his fascinations: the deep sea. His second venture into an oceanic film? "Titanic." It became the then-highest-grossing movie of all time. Cameron took home three Oscars himself.

But the film itself was never the priority for Cameron: He said he wrote the script in order to explore the wreck of the Titanic. "It was a little bit of a means to an end, you know?" he said. "I thought, `I can just go do this. All right, I need a story. Okay, `Romeo and Juliet.` You know, young, doomed love on the Titanic.` Boom! Like, instantaneous."

He found a way to use Hollywood to invest in his passion for scientific exploration. "Yeah, exactly," he said. "And then I had so much fun on my expedition that was to shoot Titanic for the movie, that I basically took an eight-year hiatus from Hollywood, an eight-year sabbatical. And I did subsequently six more expeditions for a total of seven, before I started `Avatar.`"

Cameron wrote the treatment for "Avatar" before "Titanic," but it wasn`t until 2005 that he thought the current technology could support his vision. And even then, he wasn`t sure the business of Hollywood would go along. "For years, there was this sense that, `Oh, they`re doing something strange with computers and they`re replacing actors,` when in fact, once you really drill down and you see what we`re doing, it`s a celebration of the actor-director moment," he said.

"Now, go to the other end of the spectrum, and you`ve got generative AI, where they can make up a character," he continued. "They can make up an actor. They can make up a performance from scratch with a text prompt. It`s like, no. That`s horrifying to me. That`s the opposite. That`s exactly what we`re not doing."

Cameron`s "Avatar: Fire and Ash" opens next months.

So, how does he feel a few weeks from the premiere? "Nervous!" he laughed. "Are you kidding? Always. Always."

Despite the uncertainty, Cameron is still undaunted, and enamored by the unknown. "I`m attracted, in case you haven`t noticed, by things I don`t know how to do," he said. "Because you grow and you learn. If I`m still making movies when I got an oxygen tube up my nose and I`m 87 or whatever, should I be that lucky, I want to still be doing things I don`t know how to do."

The Oscar-winning director of "Titanic" long had a fascination with life on the ocean floor. With cameras and deep-sea submersibles, James Cameron has brought the extreme environments of Earth`s oceans to movie screens in the documentaries "Ghosts of the Abyss" and "Aliens of the Deep." In this Jan. 30, 2005 "Sunday Morning" story, Jerry Bowen talked with Cameron, along with marine biologist Djanna Figueroa, seismologist Maya Tolstoy, and astrobiologists Tori Hoehler and Kevin Hand, about how exploring our planet`s most hostile landscapes can help in planning future manned missions to Mars and beyond.