Feb 20, 2024

Sanjay Bakshi, VFX Supervisor for "Elemental," on the burning elements behind Pixar's Oscar-nominated film

Pixar Animation Studios' 27th feature film, "Elemental," is currently nominated for multiple awards, including six Academy Awards for Best Animated Feature and Visual Effects Society Awards. This sweet romantic comedy is the labor of director Peter Thorne, who drew inspiration from his family's immigrant experience.

The result is a hilarious, bright, and colorful examination of compassion and incompatible elements. Amber Lumen (voiced by Leah Lewis) plays the hot-blooded Juliet as an anthropomorphic fire spirit, who falls in love with her watery Romeo. In the isolated district of Element City, they find love.

"Elemental" was produced at Pixar for seven years, three of which involved visual effects supervisor Sanjay Bakshi (former technical director of "Finding Nemo," "The Incredibles" and "Cars"). Among the challenges Bakshi and his team faced in creating a metropolis facing an ocean of elementals, a central challenge was giving animators the ability to generate and act out characters made of fire and water. Sanjay Bakshi admits, "It's been a while since we started working with fire and water in computer graphics, but it's still challenging." The trick was to create characters that were expressive and that people could relate to. That's what drew me into the film."

Bakshi first assembled a small team for the rapid research and development of Amber. Says Bakshi, "We challenged ourselves to come up with an iteration of the character in four to five weeks." 'We didn't want to make it too important. We wanted to learn what we could as fast as we could. After that little sprint, we regrouped to review what we had learned, what didn't work, and what to try next."

Testing of the embers lasted six months, followed by another year of adjusting the characters, using nature and animation as references. There were "two ends of the spectrum," Bakshi notes. '[In our research] we saw realistic, almost grotesque fire characters and very simple characters. We wanted to be somewhere in between. The audience had to believe that the amber was made of fire and could be extinguished. That was the premise of the film. We had to make them feel that if she touched Wade, she could disappear. And another thing: fire is very interesting and the reason we stare at bonfires. But we did not let it get in the way. It became a marriage of stylization and realism."

Stylization involved four art-directed styles of fire shapes contained within an amber flame-like body. 'We started with a hydrodynamic simulation and a fairly complex rig that respected the shape, a 3D model of the ember's head. We constrained the simulation to that volume. But still, the flames looked very realistic, so we had to simplify the shape. We used an AI machine learning technique called volume neural style transfer, which takes a picture of what someone's drawing of the flame should look like and simplifies the flame to it"

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To define the character's physiognomy, Shading Technical Director Jonathan Hoffman built a volumetric shader and carved a red contour line into Ember's head. These lines took on the appearance of graphic brush strokes, which Pixar's technical breakdown calls "stylized ribbons." The ribbons also served as linework for Wade's translucent, watery features. Bakshi explains, "We used this to create a design unity between the amber and the wade." With Wade, I wanted to make it realistic so that the water droplets would have a natural Fresnel (lens) effect on the edges of the silhouette." With Wade, we wanted to amplify it so that he became emotional and pushed out of the background. For the embers, I used the edges of her silhouette and changed the colors to make it flow and natural. Of course, the fire doesn't do that naturally, but it helped "embellish" the character and unify the design. 0]

Wade's six-foot-long, sludgy, droplet-like nature also posed a challenge, not only in terms of his endearing malleability, but also in that his translucent form acts like a living lens. Pixar used Renderman's powerful Rix Integration Subsystem (RIS) lighting model to create a water simulation and built internal shaders that allowed the artist to fill Wade's liquid volume with poetic ornamentation.

"When I first solved Wade's face and filled it with water, I quickly realized that it wouldn't work. We couldn't read his expression, it just looked like clear water. So we thought, without any logic, what makes water 'water'?"

He continues, "We did a lot of work on the effects. We fudged Wade's caustics. We did subtle volumetric simulations to make Wade feel like he was sloshing around when he walked. We amplified Wade's Fresnel effect and made it appear as if there was a flowing simulation over his head. In doing so, he felt alive and at one with the amber - because she was always active. When he moved, drops of water fell. We incorporated all kinds of effects and hand-tuned them to fit the rig. That way we could make him feel like water, without being limited by physics."

A special moment in Ember and Wade's relationship has an abstract Norman-Ferguson-like sequence that plunges into Ember's eyes and reveals how she tries to summon tears for the first time in her life like fireworks. Peter Thorne conceived the scene to show Ember's growing sympathy for Wade. Much of it was storyboarded and choreographed by a talented animator named Amanda Wagner. Much of the storyboarding and choreography was done by a talented animator named Amanda Wagner. When they worked with Pete, we did not constrain them to any tools or pipeline."

When Wade and Ember summoned up the courage to kiss while hiding under the canal bridge, Pixar artists brainstormed a treatment with the right impact. It was almost a dance of effects," says Wade. 'Their first touch, the amount of steam, the reaction of water and fire, it was all on paper. We discussed how they would react, how it would build, and had the effects artists match their intentions. Since it was a one-off shot, we didn't have to build a rig. We forced these shots and took our time to get them right." Principal Lighting Artist Jose Luis Ramos, Pixar Director of Photography Jean-Claude Calache and Pixar Lightspeed Artist Jeremy Heinz created transcendent lighting effects. We wanted it to be magical, down-to-earth, yet very romantic, with a heightened sense of reality." Sparkling light, reflections on the water, stylized bokeh, lens effects. We put everything we had into it to make it as beautiful as possible."

The synergy between visual effects and emotional storytelling required a unique approach to the roles of effects artists and animators. They had to work together in ways they never had before," Bakshi concludes. For example, the scene where Amber gets angry required a delicate touch of choreography from the animators. We created controls that allowed the animators to not only change Amber's facial expressions and body language, but also to control the flickering of Amber's flame. We could make the flame intense, jagged, red to purple, or make her as bright as possible. These parameters then controlled aspects of the fluid simulation. We spent a lot of time building the controls so the animators could perform that way. That was the dance we had to do."