Why has Oscar-winning director James Cameron been slumming it in the documentary world lately instead of making blockbusters like Titanic and The Terminator? Aliens of the Deep, a 3-D IMAX film about the crazy creatures dwelling 3500 meters beneath the ocean's surface, opening today, marks his third foray into the genre. You could sum up his drive in one axiom: Truth is stranger than science fiction.

"You can't make this stuff up," he says of the translucent squid with ears, the fish with feet, and the film's other alienlike stars. "Every time I do a dive, that's what I think: 'Wow, I never could have imagined that!'"

Coming from the writer-director of Aliens and The Abyss, that's saying a lot. Cameron's also proud of the fact that, by making the film, he (along with Disney and Walden Media) was able to help out underfunded researchers. "We put the expedition up on its feet and invited the science community to come with us," he explains. "It's science that would not have taken place in any form otherwise because we asked scientists who did not have grant money lined up.

"[I get] a deep personal satisfaction... that I'm getting to bear witness to some of the most amazing places in the world that very few people have the opportunity to see," he continues. "As a filmmaker, I get to bring that back and share it with millions of people. I don't think it takes the place of making fictional entertainment like I've done before, and I'm going to continue to do that as well, but I enjoy this."

But fear not, sci-fi fans: In addition to promoting the lofty goals of science, Cameron will also apply his newfound skills to our baser needs. For his next feature film — a live action adaptation of the anime series Battle Angel — he plans to use the 3-D "stereo" camera technique he developed in his doc work. After that, "I have another project that's an ocean-themed fiction story, where we'll use a lot of what we've learned," he says. "It all interrelates somehow."