RP: There were some places where they'd be doing stunt capture or Jim would be doing some kind of capture and there wouldn't be an environment created yet. So we were faced with a capture file without an environment, and I came up with a system called Character Emanation or snowshoes where the characters' motions would actually generate their environment.

BD: How was this achieved?

RP: Using a particle system that emanated from our library as they moved through the space, they would generate the environment themselves. There was one scene where Zoe [Saldana's] footsteps created the branch from the tree as a result of her movements. So Zoe's performance actually built the environment. I don't think this has ever happened in the history of film that I know of. So once her body movement created the branch, I baked it out with the branch system as a complete asset and it went all the way to Weta.

BD: You worked on Tintin for Spielberg after Avatar. What was that experience like?

RP: It was very different. First of all, most of the sets on Tintin were all architectural-based, so they would be realtime representations of a room, which is a lot easier than organic jungles and plants and the transparency channel that they had. But more importantly, I think, every director implements and uses the technology in a different way because they work differently. That was probably the major difference. Steven took really well to the virtual camera and really enjoyed that. But his style is quite a bit different from Jim's. Jim is extremely meticulous hands-on in every detail of production design -- everything. But there was a larger part of Tintin, which is done for Peter Jackson at Weta. It's Peter's style and his way of doing things and he's different as well. The first week when we were shooting here in Los Angeles, Bob Zemeckis came over to see it. As far as I know, I don't think he ever came over to Jim's set when I was there. By he was shooting right next door doing A Christmas Carol. It was very interesting to hear them talk on set. Talk about differences in workflow.

BD: How did your workflow work on Avatar?