Avatar  is back in all its 3-D glory with nine more minutes and 250 more VFX shots in a new special edition in IMAX  and other theaters. I spoke with Eric Saindon , visual effects supervisor at Weta Digital, about the new CG work for this and even more footage in the upcoming Avatar collector's edition this fall from Fox Home Ent.
Bill Desowitz: What was it like going back to Avatar?
Eric Saindon: As strange as it sounds, I really enjoyed it. We went back and looked at it, and we were on this movie for five years. But I thought it was fun to work on it more for a few months. Jim [Cameron]  was a very different person, which was interesting.
BD: How so?
ES: He was much more relaxed this time. In fact, the first month that we worked on it, he was in Tahiti working, and we actually conference called in his hotel room, and he was sitting over a glass floor, where he could look and see the fish down below. He was in a very different environment and he was a little more relaxed because I think he had more faith in us, which was great. He knew what we could do and he knew our process. We work in a very strict process where we do key shots to really show him the look and then just bring everything up to that level, so it worked very quickly.
BD: So the first major new sequence is the Sturmbeest hunt?
ES: Yes, about three weeks after we got the turnover, it was cut and everyone was [relieved]. And then we got the re-release cut from Jim, and, of course, it was back in. Luckily, in Avatar, we did a lot of water effects, smaller bits of the same elements of Sturmbeest. We were actually able to turnaround the whole sequence: four minutes with 60 shots in about three months (with about 30 TDs working on the re-release), which is pretty good for the amount of effects. It's similar to the buffalo hunt in Dances with Wolves. In fact, we got that as a reference from Jim as far as the feel of what it should be. The Sturmbeest is a colorful rhino-like character.
We built one big environment and ran our Massive  simulation down through the environment and then used it to determine where the river should go, to put the depth in the river properly. We did a lot of growing plants (in a simple L system that we wrote) through the riverbed but getting rid of them where the Sturmbeest would be running, and just tried to wear it down a little bit so it had some age and it felt like these creatures would be roving through this area a lot. We used Massive for the growth of plants through the terrain, so big plants grew first and smaller plants grew in but died off if they weren't getting any light.
In fact, using the same software we use for oceans and interaction, we created a mud and water simulation together so, as the Sturmbeest run through the mud, we set a depth of water that it did a simulation through, but then below the water, we put a simulation of mud, too, so you got a good variety of mud and water kick up as these things were running down through the riverbed. Deluge is the name of our fluid simulator that we wrote for Avatar.
BD: What went into making the Sturmbeest?
ES: We did eight versions of them: the juveniles and the males and females. And through Massive, we actually plugged this information in so you could get more variety and complexity in the animation: the females try to protect the small ones a little bit and the males try to be a little more dominant in the attacks. In the wide shots we had around 200 in the herd and in the mid-shots it was closer to 30.
BD: Next is the school house sequence?
ES: Yeah, it has the Lorax in it and that was always my favorite book growing up, so I liked getting that into the movie. The school house sequence shows the backstory more about where Grace taught the kids and, as you walk around, you notice bullet holes in the chalkboard and you know something bad has happened there, so it's a really good way to show why they're so afraid of interaction with the humans.
BD: And the extended death of Tsut'sey?
ES: That's the other big sequence we added. In the original movie, you saw Tsut'sey fall out o the plane after he got shot. This shows Tsut'sey hitting the ground, falling down through the trees, like Jake did early on, and then hitting the ground. And then Jake and Neytiri come to Tsut'sey and having a dialog about Jake taking over the tribe and being the leader. It's a pass the torch scene between Jake and Tsut'sey. I really like it -- it's a beautiful scene, a very well-lit scene, and I'm glad it got back in the movie.
ES: We actually only added about five shots to that one [capped by having their braids touch and Jake's gasp]. It just happens to be the one that everyone watches and goes, "Ooh!"
BD: Anything else?
ES: He added back in the spaceship coming in to Pandora; there was a bar scene that was added in from earth where Jake sticks up for a woman; and a shot where he sees his brother's face, which transitions into his face in the end because, obviously, they're twins.
BD: How have things changed at Weta post Avatar?
ES: We've changed quite a few things in our pipeline for the better.
BD: Such as?
ES: Asset management so we can track our information a little bit better. In Avatar, some of the scenes are so big and we ended up with so much data. At the end of the day, we used a petabyte of data. So controlling all of this information and knowing where it is and getting it back was a bit of a problem. A lot of the things we're doing are just to prepare us for doing big movies again. For example, Tintin is a huge movie. The number of assets for Tintin far exceeds the number for Avatar just because it is a full-CG movie with full environments, so we needed a better asset management system.
BD: And I imagine you're hard at work improving fur simulation for Rise of the Apes.
ES: That's a huge one. And we're doing other films that are going to require a lot more simulation: The Hobbit, hopefully, at some point. And Gulliver's Travels , another Fox film, is one where we're improving our effects pipeline considerably. We're always changing our pipeline but improving it.
Bill Desowitz is senior editor of AWN & VFXWorld.