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.
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 judgements 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.
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 cells 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.
If you're having any trouble reading the fine print above, Flash lets you zoom in by right-clicking on the image and choosing, naturally, "Zoom In." from there you can push the image around using the hand tool to view any area you like.
As animation gets modernized, the exposure sheet is changing, too. Often, there's no more camera operator to whom to give instructions. Each image can be rendered directly from computer to film or video. And the images may all be stored digitally instead of on stacks of paper or clear plastic. But the X-Sheet as organizing tool is surviving this change and is seen in an adapted form in every kind of computer animation software.
Above is the Macromedia Flash time line. It has many functions in common with the traditional X-Sheet. You can see layers of objects stacked up for display as a single image. The numbered columns each represent a frame, with time marching on from left to right.
OK, often each image is photographed twice in succession or "on two's," but the point is the same.
The exposure sheet is the only communication
between the departments regarding the exact contents and nature of a scene. If
the exposure sheet (x-sheet) is filled out wrong, everyone will be confused, and
the Scene Planner will be very upset. If the x-sheet is filled out right,
everyone will "get it", and the scene planners will be happy. It's all in your
hands...
Here's a teacher's pet, A+ example of a properly filled out x-sheet:
Slugging the Sheets
The term “slugging the sheets” does not refer to physically punching
the exposure sheets with your fists, rather it is the process, at each stage, of
filling the exposure sheet in by each of the contributing people.
These are the people who fill out the exposure sheet in order of appearance:
1) Sound Technician
2) Director
3) Layout
4) Animator
5) Camera Operator
6) Director
The sound technician is the first person to fill in the sheets. They take the
information directly from the sound track and “break down” the individual
sounds. Break down means that they listen to the track and as they hear each
sound they write it down on the exposure sheet at the appropriate frame. This is
done phonetically. This means that it’s written as it “sounds” not as it’s
written on paper. At the same time they would also write down the sound effects
on the corresponding frames.
The director then goes over the sheets and indicates where specific action is to
take place. Chuck Jones would fill out the exposure sheets himself as well as
drawing the main key poses, similar to layout poses. These would indicate the
specific timing that the director wants.
The layout artist may or may not fill in the sheets. Sometimes the
responsibility of filling out the camera moves falls to the director and
sometimes the camera operator.
The animator is then responsible for filling out the levels section. The
animator may write in a rough version after they do some thumbnail sketches (see
the next section for more on this) or they might wait until they’ve done all the
key poses. They might even wait until they do a pencil test themselves and play
around with some of the timing as they shoot it and then fill the sheet in.
Once the animator is satisfied with the action taking place on the screen and
they feel the timing is right, they then fill in the final numbers.
The director then has the final say on the scene after it has been cleaned up
and inbetweened by the assistant animator and then pencil tested. If the
director is satisfied with the results, they then sign their approval of the
scene.
The entire scene then moves on to the next stages of production. The layout
background moves into the background painting department, the animation moves to
the scanning department where it is then colorized and composited with the
corresponding background and overlays (if there are any).
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.
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.
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.
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.
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 judgements made in the application of Squash and Stretch define the animators style.