Animation timing and spacing can alter the feel of movement even when the start and end poses don’t change. For example, the first frame might show a character’s hand in a down position. The last frame has the hand raised above the head. In one version of the animation, the hand shoots up suddenly. In the second, the hand rises slowly. These poses are identical, yet the character behaves very differently. That’s because the timing (how long it takes to perform the action) and spacing (the distances between each pose) differ.
As an exercise, draw a simple animation of a ball traveling across the screen. Place the in-between frames at equal distances. Play back the animation. Then make a second version where the positions are close together near the beginning and farther apart near the end. Watch the difference. With evenly-spaced frames, the ball moves at a constant speed. With closely-spaced frames at the beginning and far-apart frames toward the end, the ball accelerates. Reversing the spacing causes the ball to decelerate as it approaches the destination.
As mentioned above, timing and spacing describe how much time an action takes and how that time is divided. When combined, they control the behavior of the movement. If a character turns his or her head, the timing determines how long the head stays in position. If the turnaround takes four frames, it appears quick. If it takes eight frames, it appears slower. If the turnaround is fast, the spacing might be evenly-drawn or eased-in and out. Or the spacing might be the opposite of the turnaround timing, easing-in for a slow movement and being tightly drawn for a fast movement.
The difference is important. New animators often notice that a piece of animation feels stiff or awkward. They add more in-between drawings to smooth it out. This doesn’t always improve the animation. A sequence might look smooth and polished but move like a robot because all of the in-betweens were spaced equally. The key is that the character should follow realistic behavior, even if we exaggerate the action.
Sometimes an action begins slowly, speeds up, and then slows down before coming to rest. Think of a hand reaching out to grab something. It starts off slow, speeds up, and then slows down as it approaches the object. The character might reach for something, pause, and reach again.
In addition to altering the spacing, we can change the timing on the timeline. If you don’t like the way a sequence looks, rather than drawing new in-betweens, use the timeline to find new values. Select a series of key drawings and observe how long each drawing stays on screen. Adjust the length of each one. See how that affects the overall behavior. If the jump looks too forceful, try holding the anticipation longer, then try holding it for less time, and observe the differences. Each time, the original drawings are unchanged, yet the character behaves differently. More time spent in the anticipation phase makes the action feel more prepared; less time spent in the anticipation makes the action seem sudden.
While you’re manipulating spacing and timing, pay attention to motion arcs. A reaching hand should follow an arc. If the arc is curved, the in-between positions should stay on that curve, no matter what the distances are between them. Spacing that is evenly-drawn will have evenly-sized gaps between positions. Fast motion tends to increase the distance between in-betweens. Slow motion decreases the distance between in-betweens. Using onion skin, you can see how well the arc is preserved. If you don’t like the way the hand moves, decide whether the in-betweens are correctly spaced, whether the motion arc is wrong, or if the timing needs changing.
When watching an animation, look at it once in real time without going to every in-between. Ask yourself, “How does it look?” What does the movement feel like: Is it heavy or light? Slow or fast? Cautious or reckless? Abrupt or gentle? Once you have that answer, study the spacing and timing used to achieve that effect. Are the spacing and timing correct? Do you want the character to behave differently? If yes, change the timing and spacing. Don’t add new in-betweens just to make a difference.
