An early concept art showing Remy in the kitchen.

Raindrops even posed a challenge in the opening sequence establishing Remy's rural environment outside of Paris. When they looked at artwork early on, they realized that the raindrops weren't just rendered as little strokes. "They didn't have a straight edge, so we used that," Shah adds. "It's a compound image made up of little particles. When the raindrops hit the river, we wrote some extra programming to create some extra undulation in the water because it doesn't disappear from a rat's perspective -- it has fallout. So you have a little simulation there that solves that connection. It just so happened that it rained here in the area, so we went out and shot rain hitting the leaves, and it happened to be the same level of rain, which was a lucky coincidence."

Pixar also created some one-offs: for rolling dough, they came up with soft body solutions. Bread was a shading problem, so they created a volumetric texture, which is what you saw with the soft crumb inside. The outside texture was more of a classic surface treatment with paint and with the right illumination properties to give that sense of structure that was required.

Pixar needed to create a lot of small bodies of liquid related to cooking. They used the simulator originally written for Nemo, but with modifications along with a public domain simulator, Stanford's PhysBAM.

"The other thing I wanted was a warm, cozy movie," Calahan acknowledges. "We retained warm tones in the dark even if the rest of the scene is cool [such as where the rats live]. Harley and I were like mad tourists taking pictures of Paris. One of the things we noticed -- and I had forgotten because I hadn't been there in a while -- was how homogenous the city looks. All the buildings are very similar in architectural style and the materials they're made of -- they're all made of limestone, so they all have a warm, honey, tan color to everything that's so inviting. And there are certain colors that stand out against that landscape. You'd always see red awnings and red flags that would pop out, so we saved red for the chase sequence through Paris. I really wanted [the villainous] Skinner's scooter to be red for that very reason. And we really wanted it to take place in the fall, for the most part, and so Harley and I deliberately went there in October and tried to absorb the atmosphere of the light during that particular time of year. There's a lot of moisture then and shadows aren't so distinct. The light has a nice silvery quality to it and it's warmer. And the leaves are turning.

The goal was to create a cozy movie with warm tones. A neutral palette was chosen so that skin tones and food would stand out and look juicy.

"We spent some time looking at some of the older French kitchens. Again, we really tried to hold our palette to neutral tones so the skin tones and food would stand out and look juicy. We did put the copper pots in there, so the kitchen wouldn't look too dead."

Calahan definitely approached fur differently. "We've always had trouble trying to light fur and one of the things we've always fought against is to the Kajiya illumination model for the diffuse characteristic of fur," Calahan explains. "It really doesn't work, especially for short fur. Instead we used illumination coming more from the surface of the skin, and we got something a little more appealing that we could control. We have much better grooming tools for the fur than we've had in the past. We got a lot more variety and looks of the fur and how it behaved. With skin, we took advantage of subsurface scattering but, again, it helps to get the local color and shadows to come through."

And what about the wine? "Trying to get the wine to look good was extremely difficult and came down to the 11th hour," Calahan offers. "We worked on it for a couple of years and it kept looking awful and then one day it started working when we needed it to. We used a Merlot as a reference. Not too dark and not too light and fairly opaque."

Again, it was part of the ultimate goal: "I wanted people to leave the theater feeling hungry, she concludes."

Bill Desowitz is editor of VFXWorld.