"There is no particular mystery in animation... it\'s really very simple, and like anything that is simple, it is about the hardest thing in the world to do."Bill Tytla at the Walt Disney Studio, June 28, 1937 [14]
ABSTRACT This paper describes the basic principles of traditional 2D hand drawn animation and their application to 3D computer animation. After describing how these principles evolved, the individual principles are detailed addressing their meanings in 2D hand drawn animation and their application to 3D computer animation. This should demonstrate the importance of these principles to quality 3D computer animation. CR Categories and Subject Descriptors: I.3.6 Computer Graphics: Methodology and Techniques - Interaction techniques; I.3.7 Computer Graphics: Three dimensional Graphics and Realism - Animation; J.5 Computer Applications: Arts and Humanities - Arts, fine and performing. General Terms: Design, Human Factors. Additional Keywords and Phrases: Animation Principles, Keyframe Animation, Squash and Stretch, Luxo Jr. 1. INTRODUCTION Early research in computer animation developed 2D animation techniques based on traditional animation. [7] Techniques such as storyboarding [11], keyframe animation, [4,5] inbetweening, [16,22] scan/paint, and multiplane backgrounds [17] attempted to apply the cel animation process to the computer. As 3D computer animation research matured, more resources were devoted to image rendering than to animation. Because 3D computer animation uses 3D models instead of 2D drawings, fewer techniques from traditional animation were applied. Early 3D animation systems were script based [6], followed by a few spline-interpolated keyframe systems. [22] But these systems were developed by companies for internal use, and so very few traditionally trained animators found their way into 3D computer animation. The last two years have seen the appearance of reliable, user friendly, keyframe animation systems from such companies as Wavefront Technologies Inc., [29] Abel Research (RIP), [1] Vertigo Systems Inc., [28] Symbolics Inc., [25] and others. These systems will enable people to produce more high quality computer animation. Unfortunately, these systems will also enable people to produce more bad computer animation. Much of this bad animation will be due to unfamiliarity with the fundamental principles that have been used for hand drawn character animation for over 50 years. Understanding these principles should also be important to the designers of the systems used by these animators. In this paper, I will explain the fundamental principles of traditional animation and how they apply to 3D keyframe computer animation. 2. PRINCIPLES OF ANIMATION Between the late 1920\'s and the late 1930\'s animation grew from a novelty to an art form at the Walt Disney Studios. With every picture, actions became more convincing, and characters were emerging as true personalities. Audiences were enthusiastic and many of the animators were satisfied, however it was clear to Walt Disney that the level of animation and existing characters were not adequate to pursue new story lines-- characters were limited to certain types of action and audience acceptance notwithstanding, they were not appealing to the eye. It was apparent to Walt Disney that no one could successfully animate a humanized figure or a life-like animal; a new drawing approach was necessary to improve the level of animation exemplified by the "Three Little Pigs".