Computer Animation 1 Two-dimensional Animation

Animated images are almost magical in their ability to capture our imagination. By telling a compelling story, astounding with special e ects, or mesmerizing with abstract motion, animation can infuse a sequence of inert images with the illusion of motion and life. Creating this illusion, either by hand or with the assistance of computer software, is not easy. Each individual image, or frame, in the animated sequence must blend seamlessly with the other images to create smooth and continuous motion that ows through time. Traditionally, animation has been created by drawing images at certain key points in the action. These images, known as keyframes, outline the motion for the sequence. Later, the images between the keyframes are lled in to complete the sequence, in a process called in-betweening. For example, to keyframe hitting a baseball, the animator would draw several key moments in the sequence such as the impact of the bat on the ball and the follow through of the swing. The remaining images would be lled in later, perhaps by a di erent animator. The most basic computer animation tools assist the process of hand animation by automatically interpolating between the keyframes of images or models. Animation tools have also been developed to composite together multiple layers of an animated scene in much the same way that layers of cels are used in traditional animation. Other more powerful techniques make use of algorithms that render the images from geometric descriptions of the scene. These techniques change the task from drawing sequences of images by hand to using computer tools to e ectively specify how images should change over time. A wide variety of techniques are used in the process of creating a complex computer animation such as Dis-