Easing refers to the gradual acceleration or deceleration during an animation, which helps your tweens appear more realistic or natural. Use easing to apply a special movement that makes animation tasks, such as "random" movement or a ball bouncing. You can apply eases to add a more natural appearance of acceleration or deceleration by gradually adjusting the rate of change using a gentle ease curve. You can add eases to create a random appearance to one of your properties, such as x and y for random jittery movement.
Animate provides two methods to apply easing to a motion tween.
After you apply any ease to a graphable property, any hot text in the Value category is dimmed. The easing equation controls the hot text (tweened values) and there are limitations to what that value can be. Instead, edit the solid curve in the graph using the control points or other Bezier editing tools. Alternatively, you can disable the ease and use the hot text controls, then re-enable the ease and see the outcome of your changes.
Use custom easing to create your own ease using a graph in the Motion Editor. You can also apply the custom ease to any property of your tweened instance.
The Custom ease graph represents the degree of motion over time. Horizontal axis represents the frames and the vertical axis represents the tween's percentage of change. The first value in the animation is 0%, and the last keyframe can be set from 0 through 100%. The slope of the graph's curve shows the rate of change of the tweened instance. If you create a horizontal line (no slope) on the graph, the velocity is zero. If you create a vertical line on the graph, there is an instantaneous rate of change.
You can then edit the custom ease using the standard Bezier editing controls found in other property graphs in the Motion Editor. Use this feature to create a custom curve that you can use to ease between keyframes.
To apply the custom ease to a property, select the custom ease's name from the Ease menu. The property graph updates with a dashed curve that displays the actual tweened values after the ease is applied.
Use any of the following methods to reuse your custom eases on other tween instances, or even in other documents: