“We did a lot of work on character and set-up, and then kept changing the set up while we were doing the animation,” Ramon Hui noted. “In "Antz" we had a facial system that gave us all the facial muscles under the skin. In Shrek we applied that to whole body. So if you pay attention to Shrek when he talks, you see that when he opens his jaw, he forms a double chin, because we have the fat and the muscles underneath. That kind of detail took us a long time to get right."