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Character Animation Fundamentals: Overlapping Action

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In the first part of this series we learned about the importance of timing and spacing in your animations. Now you're going to learn about the equally important principle of overlapping action or follow through as it's sometimes referred. Both overlapping action and follow through are very similar and often used interchangeably, so that's something to keep in mind. If you're jumping straight into this article, it's recommended you first check out Fundamentals of Animation: Timing and Spacing. You can download the rig files used in this series at this link: Mace_Rig. In this article, you'll learn about overlapping action, how it pertains to animation, why it's so important for all your shots and then you'll get a step-by-step tutorial on how to implement it into a very simple animation exercise. You'll learn how to use the software to your advantage to create convincing overlapping action.

Bodies in Motion Don't Move All at Once

One of the most important things to remember when thinking about overlapping action, is this, bodies in motion do not move all at once. That, in a nut shell, is the essence of overlapping action. As long as you keep that in the back of your mind as you're animating, you're golden! Pretty simple, right? Well, that just about wraps it up for this article... Okay, not really. Wouldn't it be nice if everything was that easy with animation? While defining overlapping action in an uncomplicated way like, "bodies in motion do not move all at once" is great, and helpful, but how do you properly animate and show that not everything moves at once? How do you animate a dog's floppy ears while they're running, and what should that motion look like? That's where it starts to get tricky, that's why this series is designed to teach you these principles and not give you simple definitions in the hopes that you'll learn how to implement it into your animations. Overlapping action creates fluid movement in your animations, adds appeal and more realistic motion to your shot. A very simple example of overlapping action happening everyday in the real-world is in an ordinary blade of grass. This little blade of grass doesn't move all at once, if you were to examine it closely you'd see as the wind blows and comes into contact with the blade, the first thing that happens is the very base of the blade of grass moves first, the other sections of the blade will follow suit, but not at the same time. As the base moves forward, the other sections of the grass actually move in the opposite direction, creating a type of wave pattern. This exact same example can be applied to just about every animation you do. In the real-world, if you were to jump you would bend down, then your back would follow. Your head would rotate downward. As you actually start to jump up, your legs thrust you upward, however, your spine would in fact rotate down, and so would your head. Once you got into the air, your spine and head would start to straighten. This is the exact same wave pattern that you saw with the blade of grass; conversely it's happening on a character. So where does follow through come into all of this? As mentioned above, both overlapping action and follow through are very similar and often used interchangeably, however, it's important to know, even early on in your animation career that they're slightly different. One of the main differences is follow through is something that should typically occur on objects that are being affected by outside forces, for example, the cape on a superhero, or a necklace. These are things that can move, but aren't actually driving the action. Whereas overlapping action is what happens to the driving force, a character's spine as they jump or their wrists dragging behind as they walk. Once you understand overlapping action, you'll be able to understand follow through, because it's very similar, but the scenarios are slightly different. Imagine if everything you animated happened at the exact same time. A character moving his hand up to wave would look extremely stiff, like a plank of wood rising. A character picking up an item off the ground, if all the fingers moved at the exact same time, it would look like a mechanical claw opening and closing. In a very basic example, overlapping action means making parts of the body move at different rates. How you implement this technique into your animation can be the difficult part. Another very important factor of overlapping action is that it adds weight to your animation. Making things happen at different times gives the illusion that they're heavier than they are, and that they're affected by gravity, which is what you want to get across in your animations. You can see a representation of this with the hand raising example mentioned earlier, in the video below the hand raises in one second. The next example, the elbow and wrist have been offset from the upper body. This makes the animation feel much more fluid and believable.

Overlapping Action Adds Character

The principle of overlapping action in fact goes much deeper than creating a realistic blade of grass blowing in the wind. While you'll need the principle to create the fluid motion on a squirrel's tail, or an arm slamming on a table, it's actually closely related to the principle of lead and follow. Which basically means the same thing, things occur at different times. For example, with an arm raising, the shoulder is the first thing on the body to move, and the rest of the arm will follow, i.e. lead and follow. This is essentially the same thing you're trying to achieve with overlapping action. The only difference is that it also adds a thought process to a character. Everything we do in the real-world is initiated by a thought in our brain, the brain is the ultimate driving force in every single action we take. So how can you take overlapping action further than the swaying in a blade of grass? Well, you can also overlap the timing of different actions. For example, if you see a dollar bill on the ground, you'll first see it with your eyes, next your brain will register it, after that you might bend down, and then you'll arm will extend out. You could even take this further, and delay the opening of the hands until the arm is almost completely stretched out. Each one of these actions happen at slightly different times. It goes in order like this; Eye movement, brain register, bends down, hand extends to pick it up. If all of this happened at the exact same time it would look extremely unrealistic and robotic. While lead and follow is normally referred to when implementing this form of overlap, it's essentially the equivalent techniques applied, just in a slightly different way. Things happen at varied times, whether it's in the body itself, or the timing in which we move. Overlapping action produces fluid motion, and it can also create a thought process for your character.

How to Implement Overlapping Action into an Animation

Let's learn how to begin to implement overlapping action into an animation. In this basic step-by-step tutorial we'll be animating a simple mace moving back and forth, with overlapping action applied to it. You'll learn how to approach creating overlapping action.
It's important to remember that overlapping action happens in just about every single movement we make, nothing moves at the same time. Keeping that in mind will help you create more fluid and appealing animations. For example, when someone opens their hand the fingers aren't going to extend out at the same time, the thumb will open first, and after that index starts to move, next the middle, and so on. Now that you've created your first animation implementing overlapping action I want you to take this a step further, for this assignment use the same rig, but animate it moving around the screen, in all different directions. Making sure that as the mace moves around, it will overlap correctly as it would in the real-world. Doing this assignment will not only get you more comfortable with overlapping action, but it will also really nail down the principle of timing and spacing that you learned in the previous article. In the next article of the series, you will learn about the principle of squash and stretch, the principle that's extremely important, but can easily be overdone. If you have any questions be sure to post them in the comments below. If you want to share your progress with the series so far, and show off some of your work, we'd love to see it! If you're new to animation, be sure to download our handy Principles of Animation PDF to keep as a reference guide!