This chapter examines two-dimensional (2D) and three-dimensional (3D) animation principles and techniques. Animation is the underlying mechanic on which the visual aspect of computer games is built. Animation is possible because of biological phenomena involving the human eye. The traditional technique for producing animation was to hand draw each image, known as a frame, and display them one after the other. Early Disney cartoons were produced in this manner. Animation in the very first computer games was the result of using vector graphics to draw an object on the screen, clearing the screen, and redrawing the object at a slightly different location and rotation. Anime Studio Pro is a 2D animation software package that will take an image of a character and allow people to add their own bones. Biomechanics plays an important part in animation describing the way in which natural hierarchical systems such as the human skeleton move.