Inspired by the classic Disney short, Susie the Little Blue Coupe, animators designed special eyelids and eyebrows for the windshield to communicate expressiveness in the cars. © Disney.  

“We had to invent something on the fly based largely on the great story drawings… suggesting a stare step in the middle down to multi area use of the body. Those fenders kind of feel like cheeks if you angle them up a bit so that they cradle the bottom of the pupil as it looks out, or they could be like shoulders. It really became a matter of the animators’ interpretation for the specific needs of the scene exactly how these different parts of a car would be designated as parts of a character. So that was definitely another challenge too. It’s a tribute to the variety of movies being made at Pixar now. A lot of the guys who took to The Incredibles really easily had to struggle a bit at the beginning of Cars. They had to relearn these new rules.”

Not surprisingly, there was considerable trial and error, particularly in getting the eyes just right. According to supervising td Eben Ostby, the first few times they put the eyes in the windshield they looked funny. “The far eye looked like it was a different size. Perspective didn’t work well with the eyes on a flat windshield. They looked distorted even though they were the projection of a round thing on a windshield. We cheated them a little bit. We had a system that would change shapes slightly to counteract the effects of perspective. It dialed down perspective, which is something we never did before. [We came up with] a solution somewhere between complete perspective and new perspective.

It took considerable trial and error to get the eyes right. Animators had to cheat the perspective so the eyes wouldn’t look distorted. John Lasseter is very specific about how eyes should be illuminated in his movies.  

“The way John likes to see eyeballs illuminated is very specific on all his movies. He likes to have a hot spot on one side and a glow on the opposite side of the iris and that needs be driven by the light source but not slavish to the point where you take creative control away from the animators. It’s a slightly cartoony feel.”

A great epiphany occurred early on during testing for a character named Luigi (Tony Shalhoub), a gregarious ‘59 Fiat 500 that runs the local tire shop in Radiator Springs. In trying to personify Luigi’s gregarious nature through movement, they hit upon a way of pirouetting that opened up all sorts of opportunities for the other cars as well.

“The Luigi test was done by [directing animator] Bobby Podesta,” Sweetland offers. “The epiphany there was you’re trying to search for the line between fantasy and reality. As I was saying, with truth to materials, it’s about finding touchstones or details that ground this cartoon character in a reality, yet at the same time it’s a fantastical situation, especially in Luigi’s case, who is really full of life. It’s funny because after you see a test like that or you see a movie, a lot of this seems self-evident. But that’s the point of all of this work: you want to make it seem effortless and natural. When you really don’t know the rules yet and you’re feeling your way through this developmental animation, a test like that can be a beam of light that shines down. It made you take for granted that this was a living thing. That’s one of the tricks of animation: to sell that this thing really does exist. The test had the flights of fancy as well as the important aspects of weight and physics — a logic that helps you understand that this is the real thing.

In this progression from Cars, view a storyboard, wireframe, animation render, occlusion, ray traced occlusion and reflection and final lighting and rendering.  

“For me, I always find certain gestures fascinating when you consider that they could only happen when a character has lived an entire life in this body. So one of the things I enjoyed doing was finding gestures really specific to a car [as though it were] a living thing. For instance, rocking back and forth on its wheels. Actually, it didn’t end up being in the movie, but I tried some of that with Mater. I think it goes with his character because he is very comfortable in his own skin. He is one of the most natural characters in the movie or in any Pixar movie. I wanted to get a sense of his internal reality. There’s a question [here] that only animation can answer: When do they engage their brakes? There are times when they are able to move forward with gas power. But there are also times when they feel like they are able to manually roll their own wheels. And there are other times when they can obviously release their wheels and just coast. So these are the kinds of opportunities that animation can provide.”