James Cameron "didn't know what he was doing" when he directed 'Avatar'.

The director didn't understand what was going on during production of his latest film, the sci-fi epic 'Avatar', because the 3D filmmaking process was so technologically advanced.

He revealed to Britain's Live magazine: "Occasionally, it was like herding cats. We weren't out at sea, we weren't fighting storms - we were fighting the fact that we didn't know what we were doing. We had to make up a terminology because we didn't know what to call things.

"It got to the point where I could go down there and tell them I wanted to shoot scene 72 and they'd build the set in 15 minutes. We'd shoot a bit, then go and figure out more stuff, and then we'd shoot a bit more.

"We thought that this film was going to be a controlled process. We were going to capture the actors and then we were going to shoot with virtual cameras. Finally we'd have the film all cut. What we didn't realise is that you edit everything twice in the virtual world. The first 62 days of this year were non-stop work."

James - who shot to fame with the box office hit 'Titanic' - believes this new movie technique is a "revolution" and is hopeful his latest cinematic offering will stand well against competitors.

He said: "In the cinema, 3D is a revolution. 'Avatar' will have its part in that revolution. Hopefully it will show that a 3D live-action blockbuster can be successful. 'Avatar' will be the test case."