Principles of Animation: Ease In and Ease OutDavid 04.15.2013
Easing is an technique that lets an object realistically accelerate or slow down. Ease in is when the motion begins slowly, before gaining speed as time progresses. Ease out is when an object in motion will slow down before coming to a stop.
Take a look at an example below from an explainer we did for Tworkz. In this clip, the woman simply raises her right arm. She begins slowly, and then increases her speed. While her shift in speed may be subtle, this technique adds a level of believability that would not be there if her arm just suddenly lurched upward.
Let’s look at another example from a spot we did for InTown Discounts. In the clip, a woman is retrieving a sheet of paper from a printer. As she pulls it towards her, her movements are quicker, and the majority of her movement is displayed in only three frames. Yet, as she eases out of her motion, there are a much greater amount of frames used to show her arm settling into a resting position, and finally to a stop.
In other words, to slow down the action the number of drawings needs to be increased, and, subsequently, decreased when the motion quickens.
The end result of easing should help the action become softer, and the motion more fluid and realistic.