Level: BEGINNER |
Overlapping action is another vital principle of animation. In this tutorial, we look what it is and how you can apply it in your own work, together with some of the other principles of animation to start building more advanced movements.
INTRODUCTION TO OVERLAPPING ACTION
Overlapping action is simply how we animate objects that are attached to or extensions of our main animated subject. It’s that characteristic lag behind the main object and how they continue to move along the same path of action even when our main object has changed direction. Examples include drapery, clothing, tails, floppy ears, capes, hair etc. Like many of the animation principles, it may seem stating the obvious as this is how objects behave naturally in real life. However, like many of the principles, it’s surprising how often we forget to consciously add it to our work and how our subconscious picks up on this oversight, signified by a faint sense of awkwardness or discomfort when watching the animation.
Overlapping action is often paired with principle of Follow through.
Follow through is specifically when an objects stops moving and periphery objects that are attached to or extensions of the main object continue to keep moving before settling to a stop, usually a few frames after one another. To be honest, I think that they are much of a muchness. I think that the spirit of both terms – overlapping action and follow through – point to the same law of physics: inertia.
We all know that inertia is a property of matter “by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force.” Overlapping action and follow through is how we show this inertia as it effects objects attached to or extensions of the main body in motion. Where ever the main body of motion goes, the attached objects will follow BUT with a few frames delay, depending on weight, material, wind resistance and whole host of other physical properties of the dragging object.
OVERLAPPING ACTION IN ACTION
In the bouncing ball example above, we’ve attached a racoon-tailed hat to the bouncing ball. To get the tail of the hat to move convincingly as a result of the ball bouncing, we need to apply the principle of overlapping action to it.
You can see that with the fairly light weight material of the tail, air resistance is playing quite a big part in the motion of the tail. Therefore the overlapping action of the tail doesn’t just lag a few frames behind the ball in a vertical motion path. Air resistance means that it follows more of a figure 8 motion.
This brings into play another principle which we’ve already looked at: Arcs.
Specifically, two ‘S’ shaped arcs – an normal ‘S’ on the way down and a backward ‘S’ on the way up. Together, they, the tail looks like it is making a lovely figure 8 motion. To be honest, as an audience member, it’s unlikely you would consciously notice this but arcs are a natural part of motion and its something that you feel, especially if the motion of objects don’t travel along smooth arcs.
When you break down animation like this, you’ll begin to notice other principles of animation at play. Besides the squash and stretch of the ball, notice the squash and stretch of the tail itself
Overlapping action is the way periphery objects that are attached to or extensions of a primary object drag behind the primary object as it moves. When there is more than one object dragging behind it also is used to describe the differing speeds at which the objects drag (more on this in the jumping flour sack tutorial). Overlap is closely linked to Follow through which has the distinction of how objects continue to move past the primary object when it has stopped moving. Like many of the principles of animation they are just an implementation and exaggeration of the forces observed in the real world.
Despite still using a simple mass, you can see that already, the principles are beginning to stack. It’s not just the principles of overlapping action taking place but also the principles of arcs and squash and stretch. By turning on the onion skin tool in the resource file for this tutorial, you can also see how the effect of timing and spacing plays out on this animation too.
When first learning about the principles of animation and the numerous ways they can be applied and implemented into your animation (both consciously and unconsciously) it may seem like spinning a lot of plates. This is why the bouncing ball is such a great tool because it keeps things as simple as possible for as long as possible, until the principles discussed start to become intuitive.
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