We also had to deal with this cheese ball bag, where one of the characters is jumping on it. There are some subtle physics going on in the tension of the bags themselves.

BD: Harder than the cheese balls?

DS: Yeah, the cheese balls themselves are straightforward; the bag they go into turn out to be very tricky. There are some really specific things that happen and you hope that the solutions you use with cloth can work for a lot of different surfaces. They get you part way there and then you have to start finding other solutions to these shape issues that occur with deep folds yet flat surfaces that occur on these packages. And the kind of wrinkles you get are very easy to spot yet subtle and need a while to iron out all the problems.

BD: You must be pleased about getting short-listed for a Best Animated Feature Oscar nomination.

DS: Absolutely. CG work is still an undefined quantity and everyone is trying to figure out how it all fits together and how the traditional category names fit newer methodology. So, it is pleasing to see that and it just helps everybody to have it recognized for how much work goes into this kind of thing. And one of the issues with this film is that there are seven characters and close to 800 shots had to be done and when you get six furry characters with costumes singing in a lighting environment that is concert oriented, and you have a short schedule, it's a complex task with just background issues, like having a very robust pipeline to deal with many aspects of a shot changing simultaneously, and different versions of characters having to appear in different shots at different times.

Bill Desowitz is senior editor of AWN & VFXWorld.