Issue link: https://digital.copcomm.com/i/1505509
www.postmagazine.com 23 POST JULY/AUG 2023 same amount of water is just being moved around and the shape is changing. We had slide controls, so you could grow the water mass, say, in his arm. Then you would be able to slide that up and down between his shoulder and his wrist to get the sense of that bouncy, watery overlap or that sloshing around internally." A dynamic rig also controlled Wade's character outline, allowing him to maintain fluidity and trans- form into different shapes throughout the film. "He had quite a robust outer shaping rig, so you could really manipulate his form," Rutland notes. The film's air characters posed a major chal- lenge for the animation team, as they had vastly different physical properties from the fire and water characters. "We decided early on that we wanted them to feel very light, very low gravity," recalls Enderoglu. "Because they're so fluid, we wanted their features to be drifting and dragging around. The computer doesn't do fluidity very well on its own, so a lot of that was hand keyed by the animators." EFFECTS SUPERVISOR STEPHEN MARSHALL With significant effects work in every frame, it was essential for the effects department to expand its typical pipeline. The workload was split between two parallel groups: shot effects and character effects. As a part of the latter team, effects super- visor Stephen Marshall helped bring the film's fire, water, earth and air characters to life on-screen. The character effects team was able to expand on relevant technology from previous Pixar productions. "We actually built on top of some work that was done on Soul (2020) originally, where they had to solve some problems of how to create a subset of volumetric characters," Marshall recalls. "Ours was a much bigger task, where pretty much all of the characters were either volumetric or simulated or both. So we had to come up with techniques to be able to simulate these characters efficiently, be able to make sure that they were expressive, make sure that they could perform, and be able to deploy it across 1,600-plus shots." This daunting task required the effects team to rebuild their workflow and engage in more cross-department collaboration than ever before. "We were collaborating with other departments we never collaborated with before, like characters and animation," Marshall notes. "And then on top of all that, we were trying to come up with a common language. We'd never talked with each other be- fore, and we had to start understanding what our roles were about." As production was taking place remotely, Zoom meetings and virtual collaboration tools kept the communication on track. This was a major depar- ture from the typical Pixar effects workflow. "We're usually a downstream department," Marshall explains. "Characters will be done, ani- mation usually still is running, but the shots that we get started on, they're already done. If we ever need help from animation, we could always go back. But in this case, we were working with them. We would meet all the time with animators, talk about things that they're trying to do that maybe our rigs are supporting, how we can improve it and how we can help them." The effects team relied on Houdini for the bulk of their workload, along with customized propri- etary tools. "We also had to write a lot of custom solvers, particularly for our fire characters," Marshall ex- plains. "We had to augment their pyro simulation to be able to target shapes." The team would also modify fire simulations to run at much higher resolutions to deliver increased sharpness and more control. It was very important to develop effects-based solutions that would not impede the animation team's process. "We don't want to create constraints for them," Marshall adds. "We had to create a system that adapted to anything that they threw at us. It had to be as automatic as possible." VFX SUPERVISOR SANJAY BAKSHI When VFX supervisor Sanjay Bakshi first had a chance to see the film's storyboards, he under- stood the obstacles that lay ahead. "Every shot was an effects shot," he recalls. "Usually we have a few hundred effects shots, and this was the whole movie." Houdini played an essential role in the VFX team's workflow, augmented by an arsenal of pro- prietary tools. "Every shot of Ember and Wade goes through Houdini roundtrip," Bakshi shares. "Animation saves their file, the simulation gets applied by Houdini, and that comes out so that we can ren- der it in Renderman." The team also used Katana for lighting, Nuke for compositing and Maya for modeling, among many other specialized tools. Pixar's proprietary tools were especially tailored toward flame-effect customization. "We have a proprietary machine learning-based stylization for flames that integrated into Houdini," Bakshi notes. "The pyro simulation is done in Houdini and then sent to a program that we've written with Disney Research to stylize the flames, and then it goes back into Houdini." Pixar has been integrating machine learning into their VFX pipeline in recent years, including a denoising tool that has been utilized since the production of Toy Story 4 (2019). "We have a path-traced renderer, which is Renderman, and we run it until it converges pretty well, but it's still pretty noisy," Bakshi explains. "Then we use a proprietary denoiser that's machine learning-based. It's been trained on a bunch of Pixar content and it can denoise really well." USD (Universal Scene Description), an open col- laboration framework originally developed by Pixar, was integrated into the background of the project's VFX workflow. "Our proprietary software, Presto, uses USD in the backbone," Bakshi explains. With VFX required for every shot, the team made sure there was ample time in the production cycle to complete the full workload. "Normally that happens pretty rapidly after animation is done, but we gave ourselves a longer window," Bakshi recalls. Director Peter Sohn was very involved with the VFX process and established an open line of com- munication with the team. "We had a lot of time with Pete — showing him the effects, having all the effects artists in the room, talking about what was working and what wasn't, and learning what his taste was." Overall, Bakshi was thrilled to have the opportu- nity to work on Elemental. "I enjoyed building and working with a team of passionate, like-minded people, and then working with Pete, who is so imaginative, so generous and has a real vision. It was kind of like the highlight of my career to work on something this challenging with a bunch of people that are so passionate and so interested in doing something unique." Ember's fire effect was one of the film's biggest challenges.