James Cameron's been out of the feature-film business for years, so to jump back in, he'd better have something pretty damn special. And fans in attendance at his Comic-Con panel Thursday, during which he premiered a sizeable chunk (some 20-25 minutes) of brilliant 3-D footage from his new film Avatar, definitely got what they came for.

For those who've been following the Avatar saga--his first feature film since Titanic and a project he's kept under lock and key--this was a huge reveal. And it was star-powered, too, of course. Before the footage we got to meet castmembers Sigourney Weaver (stately a la Hillary Clinton and still plenty sexy), Stephen Lang, the gorgeous Zoe Saldana (below), and (via a special Comic-Con video greeting) Sam Worthington; each came to the mic to give a bit of background on their character (and in Lang's case, doing so in character) and how they fit into the storyline.

This parade of stars was professionally orchestrated--their appearances weren't just for mere photo opps, they were integral in building background on the world Cameron has created for this film, and for building us up to what was truly the panel's main event: some 20-25 minutes of footage from the film, screened for the first time anywhere in the world, all of it presented in 3-D on the big Hall H screen.

Talk about knocking your socks off. The first scene was in a science lab on the planet Pandora, which introduced us to the main characters and their avatar bodies. The rest moves us into what is the heart of this film: the jungles of the planet Pandora. We saw a couple of impressive fight scenes between Worthington (or to be more precise, his new avatar-body) and some of the local creatures, but what the footage accomplished best was allowing us to bask in the planet's landscape of bright flourescent colors and glow-in-the-dark plantlife. Any self-respecting prog fan will immediately think of Roger Dean's artwork on Yes album covers; even moreso, it felt like an undersea fantasy world, like you see in elaborate saltwater fish aquariums, with their crazy-colorful stones, dreamy plantlife, secret chambers, and all manner of exotic creatures moving fluidly through their environment. Of course in the case of Avatar, the 3-D presentation pushed the fantasy into a whole new realm.

(See SciFi Squad for larger versions of this conceptual piece and one other image)

There were clear reference points in the footage, including Jurassic Park (for the lab-experiment-gone-wrong scene), Star Wars (duh), and certainly Aliens (the close-up faces of Pandora's creepiest creatures carried more than a slight resemblence to the Alien monster). Those are just the most obvious, I'm sure you can find plenty more.

Overall, though, the scenes and the carefully orchestrated story and character background did what they came to do--get fans fired up for the real deal later this year.

The final reveal came when Cameron announced he'd be showing some 15 minutes of Avatar footage free in numerous IMAX and 3-D-equipped theaters worldwide on Aug. 21. For more info on that, and a bit more of a nontrailer tease (a bit of music, a brief image), the Official Avatar Movie site is now live.