For Episode III, which Knoll characterizes as evolutionary rather than revolutionary, the ILM team pushed CG mostly for greater efficiency. For instance, they incorporated radiosity for the first time into the pipeline, thanks to faster computers, to achieve greater photorealism for both characters and environments. They also took advantage of a new iteration of the company’s fluid sim engine to achieve authentic-looking glowing lava (using the thickening agent methylcel) on Mustafar. “Volume is a big issue so you have to carry a big volume grid in memory. We implemented an octrie computer memory representation, allowing high res fluid sims with nice detail where you want it.”

According to Coleman, on Episode I animators ran their own simulations with help from the creature development team. On Episodes II and II, however, all simulations were passed off to a specialized sim team or creature dev team that handled all cloth, hair and rigid body (such as a droid getting slashed in half or a ship that crashes and breaks apart). This became a very efficient form of specialization. “Five or 10 people worked on this and became very, very good at it. We didn’t understand in the ‘70s how vast George’s imagination was. This world is fully realized in his head and you can ask him anything.”

CG Yoda and MoCap advances were some of the highlights of Episode II.

Meanwhile, the cloth sim program has come full circle in Episode III. “Yoda’s robe is more worn, so we have this fuzzy level on top of the clothing that we weren’t able to do before,” Coleman explains. “That has been rolled into this movie. The cloth simulation program was written specifically for Episode II and we were happy where we brought the clothes, especially in Yoda’s fight. We worked on the new Terminator and Pirates of the Caribbean and when we started work on Episode III, we realized that they had made great strides in Pirates that had given greater control over the simulations, the turnaround time for the shots was faster, they put in some new tools to achieve clothing at a much more realistic level, so that was all rolled into Yoda for this movie. To me it’s a cornerstone of whether we’re going to be successful or not because here we have a little green man who wears exactly the same clothes as Ewan McGregor, and they’re in some of the same shots together and the digital wind has to work with both of them. And when they jump and leap it has to look the same.”

More significantly, however, was a major layout change on Episode III: “We did an informal layout process on the first two prequels,” Knoll continues. Peter Dalton did a layout phase on the pod race for Episode I to get continuity correct. He took it to final edit plotting out who goes where and when. He did the same thing on Episode II with the long action sequence toward the end. So with Episode III we instituted a layout department [supervised by Brian Cantwell] that figures out continuity issues and works out cameras together as a sequence.

“If we needed a modification to a camera or something needed to be laid out in a sensible way, he took care of it before it got to the animators and TDs. There were sometimes problems in the past when Rob and I had to look at matchmoves or approve them to go to the animators or TDs. We’d look at a particular shot in a sequence and it would look fine until it went to the animator. And we’d kick it back. The [new] layout department would preflight them correctly before they got to the next step in the pipe and that meant a lot less kick back, and it would be a lot more efficient.”

Coleman concurs: “John and I worked on all three films and the gotcha part was the beginning of the pipeline. We needed an overall supervisor to figure out the continuity of where a shot fit within the overall sequence. And in computer graphics, when you’re interested in three-space, does it fit logically with the computer lighting and computer characters?”

This was never more evident than in the bravura opening battle, which is like an amusement park ride and which Coleman terms the biggest space battle of all time. “There’s 10 minutes of small and large fighters zipping and zapping. On previous films, I focused my team on creatures and droid work and on this film George wanted to build on the experience ILM had on Pearl Harbor and raise the bar with this ultimate battle in space. I got Scott Benza and Paul Kavanagh, who worked on Pearl Harbor, specifically on fight dynamics. We travel with Obi-Wan and Anakin… zipping right over camera and the equivalent of battleship row, except floating in three-space around in different angles, various fighters bombarding each other, while little fighters fly in between them.”