Introducing Plume for Firebending
However, Shyamalan was adamant that the elements look as naturalistic as possible. Water, as always, proved difficult because of its complicated nature, and Zero G water tests from NASA proved instrumental in figuring out how to convey the flow of water that the director requested. Air was a design challenge because of its abstract nature, so it was decided to use the available environment for a wispy look. Earth was not so difficult because it was only used in a couple of scenes and could be attained through the use of Fracture (Star Trek, Indiana Jones and the Kingdom of the Crystal Skull).
But fire was the most challenging, not the least of which because the director didn't like the look of real and CG fire alike. So ILM had to come up with something new to generate fully-directable photorealistic fire. Plum is unique in that it not only serves as a fully volumetric simulation engine but also as a renderer.
Taking advantage of the latest NVIDIA GPUs (the 5800s), Plume gave the vfx team an eight to 10-fold speed increase in generating simulations and renders for hero, middle-ground and background fire effects. This meant that artists doing complex simulations that had previously taken eight hours (overnight) to compute a single iteration could now get six to eight iterations a day -- fully rendered -- thus providing great artistic flexibility and shortening the time it takes to complete shots substantially. (You can check out the SIGGRAPH Talk about Plume: July 25, 3:45 pm, Rm 515 AB, Los Angeles Convention Center).