Tracking Down The Na'Vi (And Some Humans)

Technology is a wonderful thing, but it can't quite yet create human performance out of thin air (though we're sure Jim's working on that one too).

No, to bring the characters of Avatar to life, Cameron required some actors.

"We were making a $200 million-plus movie and it's all about the journey of one guy, Jake, and he’s in every scene in the film, from beginning to end. It all hangs on that one piece of casting," says the director.

Cameron saw hundreds of actors, established and unknowns, but he needed someone who fit the role. Then he saw Sam Worthington's audition tape with a scene in which he has one line, "Uh huh."

"Sam had me at 'Uh huh,' " Cameron told the audience at the Australian Film Awards, where he was presenting a gong to his star. "He's an old-school tough guy, and that's what I needed for this film.

“Sam is able to create a character that allows you to walk in his shoes. He’s so good at communicating his emotions without appearing to do anything.

"It was a very challenging film for him, because he plays part of it as his human self, and part of it through his Avatar – a fleshy character, but played entirely through performance capture.”

Worthington himself seems to share the feeling - and was excited about working for Cameron. "I just want to work with people of high calibre, whatever kind of genre,” the actor told the LA Times

“I don’t basically go, ‘I want to make a movie of this type’ or ‘I want this genre.’ I look at who’s making it and who’s in it. With Avatar, they tell me Jim Cameron is directing and Sigourney Weaver is in it? Sign me up.”

An even tougher character to pull off was Na'vi Princess Neytiri, the woman whom Jake falls in love with and our link to the culture of Pandora.

But Saldana has similar feelings to Worthington as to why she took the part.

"James Cameron. It's not everyday you get a call like that where, 'James Cameron wants to see you for this role.' You just know that it's going to be amazing.

"It took him 10 years between projects because he works so hard and pays attention to detail. It's undeniably exquisite. That's pretty much what attracted me."

While he was largely focused on relatively unknown actors, Cameron did decide to reach out to one veteran - old pal Sigourney Weaver, who he'd known since Aliens.

"We kept in touch, but not a lot. He was kind enough to give me my star on the Walk of Fame. He came and did that," explains Weaver.

"But you know this is the first movie he's done in 11 years. It is a kind of the culmination of his fascination with science and his concern about the planet.

"And I also think it's a wonderful love story about family and community and the miracle of unspoiled nature. I think it has a lot of details in it from all of his explorations underwater. He really is a man of so many parts, and it's all in the script. So it's very exciting to read it."

With his cast signed on, and months (or even years) of pre-production out of the way, it was time to actually shoot the physical portion…

Next: Getting It Made