A colossal budget, visionary technology and a down-to-the-wire workload on a film whose fortunes are a real question mark.

James Cameron has been here before on little ditties called "Terminator 2: Judgment Day" and "Titanic." In case anyone's forgotten how that worked out for him, "Titanic" stacked up 11 Academy Awards, best picture and director among them, and a record $1.8 billion worldwide at the box office.

This time, Cameron's vision is riding on "Avatar," a science-fiction epic aiming to push the bounds of digital filmmaking and 3-D presentation into the heavens, with a reported price tag well in excess of the $200 million spent to make "Titanic."

Will audiences come along? Cameron thinks so.

"It's hard for me to imagine that short of some massive marketing debacle, that it's not going to work for people. I mean, we may not have a kind of slam-dunk opening weekend that settles the whole case. I don't think the case is going to be settled until week two or maybe week three," Cameron said in an interview only days after completing "Avatar," just in time for its worldwide blowout Dec. 18.

"Let's face it. It wasn't settled on `Titanic' till week 10. `Titanic' was the No. 1 picture for 16 weeks. I don't expect that kind of performance out of 'Avatar.'"

Cameron will not divulge what he does expect out of "Avatar," wisecracking that "if we announce the sequel, then we hit the number."

The director, who had a $200 million smash on "Terminator 2" and hits on "Aliens" and "True Lies," has kept fans waiting a long time. Though he's been busy producing, making the underwater 3-D documentaries "Ghosts of the Abyss" and "Aliens of the Deep" and developing the technology for "Avatar," this marks his first narrative film since "Titanic" 12 years ago.

Cameron's reputation and a mammoth marketing push by distributor 20th Century Fox virtually guarantee hit status for "Avatar." Still, in this blockbuster age, there are hits and there are HITS. The question is whether "Avatar" can climb to the $300 million or $400 million level of such franchises as "Star Wars," "The Lord of the Rings" and "Spider-Man."

Some factors in its favor:

? Science-fiction and fantasy have gone mainstream in a huge way since Cameron's last foray in the field.

? Now that cartoon hits have built fan appetite for digital 3-D films, "Avatar" is Hollywood's big test for the future of live-action movies in three dimensions. "Avatar" in 3-D will bring in about $4 to $5 a ticket more than the 2-D version.

? Cameron's a franchise unto himself, a digital-effects trailblazer who always dazzles, even when he doesn't score a runaway hit ("The Abyss").

"I was watching 'The Wizard of Oz' the other day, and I thought, that's 'Avatar.' That's what 'Avatar's' going to do to people," said "Aliens" star Sigourney Weaver, who reunites with Cameron this time as a scientist overseeing a program that allows humans to take on alien forms to explore — and exploit — Pandora, the distant moon of a planet orbiting Alpha Centauri. "Because it's so bold, and it's so out there, and it's such an experience."

Some factors against it:

? Set in the 22nd century, "Avatar" is not based on a literary work, a comic book, a TV show, a theme-park ride or a toy. Cameron is asking audiences to turn up for something entirely unfamiliar.

? Cameron's also asking people to go along with a love story between a 10-foot-tall blue female with a long tail, a member of Pandora's Na'vi race, and a man whose consciousness has been transplanted into an "avatar" that resembles the Na'vi. Not exactly Rose and Jack aboard the Titanic.

? Instead of Leonardo DiCaprio and Kate Winslet, already solid stars before "Titanic" made them household names, Cameron's lovers this time are relative unknowns Sam Worthington and Zoe Saldana. Both had breakout roles in sci-fi franchises last summer — Saldana in "Star Trek," Worthington in "Terminator Salvation," a continuation of Cameron's creation. But the two are not yet box-office draws themselves.