YOU, Inc - Animagination

Glossary of Animation Terms

Anticipation: Lifelike movement is a primary goal of animation. Early animators observed nature (including themselves) and experimented with techniques for making animated actions more closely resemble their natural counterparts. An important insight occurred. In many instances, a movement in one direction is preceded by a smaller preparatory movement in the opposite direction. My imitating and exaggerating these small anticipatory movements, animated drawings were given a more naturalistic appearance. By grossly exaggerating them, a comic effect is added.

Nature abounds with examples of this principle. The more carefully you observe living things, the more you will notice it. It is partly a matter of physics. In order to move a mass efficiently, a force must be directed against its center of gravity. Aligning the mover behind the center of gravity of the mass (for pushing) or in front of the mass (for pulling) produces part of the anticipation motion. Also, muscles work more effectively if used through their full range of motion. Thus, "winding up" your muscles and skeleton produces a more powerful stroke of the bat, the golf club, the ax or the boot.

Cycle: A group of images that comprise a complete action by the subject. During a cycle the subject starts and ends in the same position. For this reason, the same action can be repeated over and over without redrawing. Cycles can be constructed for walking, running and jumping motions, gestures of the hands or whole body, or facial expressions. They are frequently used by animators for mechanical actions, or for moving backgrounds. In the latter case, a character may be shown in the foreground, involved in a running cycle, while the background images stream by behind using a cycle of repeating pictures.

Ease In - Ease Out: Though the frame rate of animation is usually constant, natural motions usually appear to begin gradually and often end gradually. Mimicking this kind of motion in animation requires a special technique.

As the animator draws inbetweens, she is constantly making judgments about how far to move the action along from one frame to the next. When a motion begins, the amount of change from one drawing to the next is kept small, but gradually increased. This is called "Easing in." When the motion is underway, the changes from frame to frame are held constant. When the motion ends onscreen, it is often stopped gradually, by reducing the amount of change from frame to frame of the moving object. This is called "Easing out." With practice, finding the right amount becomes second nature.

Exposure Sheet: Finished animation consists of many frames of film or video. Unlike live action, where the camera is running continuously, each frame of animation film is shot one by one*. This means there are big stacks of individual images as the film gets underway, and with cell animation, a single shot might consist of numerous cels stacked up together.

Since there might be several people handling each image as it makes its way to the camera, there needs to be a systematic way of keeping track of the individual pictures (often numbering in the thousands.) That's what Exposure Sheets (or X-Sheets, or Dope Sheets) are for.

They started as a place to record instructions for the camera operator, but they have accumulated a lot of other uses over time. Often, they will begin to take shape before any final drawings are made for the film. Once the soundtrack is recorded, it can be entered on the X-Sheet, using the rows of empty frames as a kind of time line. With spoken words spelled out vertically along the page, animators can tell on which frame they will need to draw the mouth shape corresponding to each sound.

In-between or Tween: An image drawn to show a character between the extreme moments of action or gesture. Tweens create smooth motion between keyframes where the action is most dramatic. Tweens are hand drawn in traditional animation, or computer generated for 3D and effects style animating.

Keyframe: An individual image exhibiting the extreme of an action or gesture. Used as a guide for the construction of intermediate frames (In-betweens.) Stops and changes of direction also occur at keyframes. CG animation moves objects in one keyframe into their new position in the next keyframe so that the animator need not individually create the intervening frames.

Onionskin: The name is taken from the translucency of onionskin paper... This technique originates in traditional cel animation. By drawing on a translucent medium, with a light source beneath the drawing surface, an animator can see the position of an object on one page, while drawing it in a new position on the page above.

This useful property of paper has been brought forward into the digital age. Many software applications offer drawing layers with a translucent quality. This makes 'tweening a lot easier. In Macromedia Flash, the layers are shown progressively more opaque, to assist in identifying the stacking order of the layers.

Panning: The motion of a film image across the field of view as the camera turns. The familiar sweep of the background, caused by camera motion in film, is, in animation, most often simulated by moving the drawn elements under a stationary camera.

Frequently, a background drawing larger than the field of the camera, is moved step by step across the animation table as the camera exposes frame after frame of film. Objects in the foreground appear to be moving along relative to the scenery behind them.

I examined a special case of this technique in my article on cycles. There, a repeating background element was run across the screen over and over, simulating a continuous pan. Let's look at a variant of that technique, used to simulate greater depth in the background. Here several layers of images are panned across the screen at different rates. The slower the motion of the background objects, the more distant they appear to the viewer. This illusion is enhanced by reducing the size of the distant, slower moving object.

Squash & Stretch: The judicial squashing or stretching of a character in motion. Stretching serves to emphasize the speed and direction of motion. Squashing highlights the effect of an abrupt change of direction or a sudden stop. I say judicial because like many other characteristics of animated drawing, the judgments made in the application of Squash and Stretch define the animator’s style.