Pixar's Render Farm

There's a brief footnote about their REVES volume rasterizer used in Soul World crowd characters. They simply state their render farm is CPU based and thus no GPU optimizations were required. At the highest, most practical level of abstraction, it's all software. De-coupling the artistic pipeline from underlying dependence on proprietary hardware or graphics APIs is probably the only way to do it.

https://graphics.pixar.com/library/SoulRasterizingVolumes/pa...

On a personal note, I had a pretty visceral "anti-" reaction to the movie Soul. I just felt it too trite in its handling of themes that humankind has wrestled with since the dawn of time. And jazz is probably the most cinematic of musical tastes. Think of the intros to Woody Allen's Manhattan or Midnight in Paris. But it felt generic here.

That said the physically based rendering is state of the art! If you've ever taken the LIE toward the Queensborough Bridge as the sun sets across the skyscraper canyons of the city you know it is one of the most surreal tableaus in modern life. It's just incredible to see a pixel perfect globally illuminated rendering of it in an animated film, if only for the briefest of seconds ;)