The text discusses the 12 principles of animation, which were developed by Disney animators in the 1930s. These principles, which are used to create believable characters and animations, are still relevant today, but need to be updated and expanded to address the new techniques and styles of three-dimensional computer animation. The author provides examples of how these principles can be applied to 3D animation and identifies several new principles that are needed for the medium, including visual styling, blending cartoon physics with real-world physics, using cinematography, mastering facial animation, and optimizing user-controlled animation.