By IAN FAILES
The first Cars film from Pixar Animation Studios was released in 2006. Cars 2 followed in 2011. This summer, the third installment of the franchise featuring race legend Lightning McQueen will be in the spotlight. And with each new feature, Pixar has upped the ante on the compelling stories they tell and the technology used to help tell them.
That’s particularly the case with the upcoming Cars 3, directed by Brian Fee, since Pixar has now completely adopted its new physically-based, path-tracing rendering architecture known as RIS inside of its renderer, RenderMan.
On the previous Cars films, the studio’s REYES (Render Everything You’ve Ever Seen) algorithm, mixed with some ray-tracing techniques, had been used to deal with shiny car surfaces. But, after implementing RIS on Finding Dory, Pixar also embraced the new renderer for Cars 3.
The third installment in the franchise sees race car Lightning McQueen (voiced by Owen Wilson) deal with the impact of a major crash, aided by race technician Cruz Ramirez (Cristela Alonzo), as they also take on a new foe in Jackson Storm (Armie Hammer).
The results look to be stunning, but getting there was not without some major challenges – ranging from the particular needs of highly reflective cars, to audacious effects involving mud and volumetrics.
A NEW RENDERING PARADIGM
Although just about every film Pixar makes throws up a series of tough rendering assignments, the Cars films tend to have very specific ones such as metal-fleck paint, high specular reflections, gloss coats and generally lots of reflections. These are rendering challenges that ray tracing lives for, but prior to RIS, Pixar was using ‘the tricks of the trade’ to simulate the required look.
“The problem was that metal-fleck paint has all these tiny little specks which are reflecting specular highlights at all random times and that kind of looks like noise. So we ran the risk of, if we used too much de-noising, we’d get rid of all the beauty of the metal-fleck paint.”
“Now with RIS that all comes automatically,” outlines Pixar supervising technical director Michael Fong. “We did a lot of cheating in the past and now we try to figure out how materials would really respond in different lighting conditions. And we try to model those materials more correctly.”
Interestingly, the ability to model and render those materials, such as car surfaces, in more detail and more realistically also required a new way of thinking about the things themselves. “Before,” notes Fong, “we approached it like this: well, it kind of looks like car paint to us. Now, it’s: well, exactly what would car paint be? It would have these various layers, and the metal-fleck would do this, and the gloss coat would do that.”