Hey everyone, this is Owen with Motion Array and in this tutorial I’ll be showing you how to create animations that have bounce like these examples. I’ve put together a free script called EZ Inertia that makes this really easy.
If you have some experience with this kind of animation then you probably know about the expression that creates animations like this. Well this script utilizes that expression, but it does it in a little more user friendly way with an easy way to apply, change settings, and have all the layers look to one control. To download the script just click on the link in the video description. Alright let’s get started.
Creating a Bounce Effect
So once you have the script downloaded you can install it by putting it in your script UI folder. To get there go to your applications, then the version of After Effects you’re using, “Scripts”, “ScriptUI Panels”. Once you’ve got EZ Inertia in that folder, restart After Effects and you’re good to go.
Okay, so back in After Effects you can open the script by going to Window > EZ Inertia. Then you can drag and dock it wherever you like. Now I’ll make a new composition so I can give you a quick rundown of the script. In the new composition I’ll create a new shape layer (Layer > New > Shape Layer) and I’ll add a rectangle and a fill to it. Alright, so let’s talk about EZ Inertia quickly. At the top of the interface you have the options “Composition” and “Layer”. This determines where the controls for the bounce go. If Composition is selected, EZ Inertia will make a new adjustment layer and put the controls on that. That way if you have multiple layers within a composition all using this expression you can change the settings on one layer as opposed to all of them. If Layer is selected then the controls will be put on the layer selected.
The next row of the interface has 5 checkboxes. These are the 5 transform properties and are represented by their keyboard shortcuts. P is position, S is scale, R is rotation, T is opacity, and A is anchor point. Whichever properties are checked will get the bounce expression. Next there’s an About button, Clear, and Apply. Clear will delete the expression from the checked properties and Apply will add it. So that does it for the interface, now let’s start using it.
The first thing I’ll do is add some keyframes to this shape layer. At 0 I’ll set a keyframe for rotation and scale and set both to 0. Then at frame 7 I’ll change the scale to 200 and rotation to 180 degrees. Then I’ll move to frame 20 and set a keyframe for position. At frame 27 I’ll move the shape off to the right. If you preview this now, you’ll see a pretty ugly animation. Now, I won’t say that this script is going to make it beautiful, but it’ll certainly be more interesting. With the shape layer selected I’ll check the position, scale, and rotation boxes and then hit apply. You’ll see that there is a new adjustment layer called “Physics Adjustment” in the comp. If you go to the effect controls you’ll see three sliders called Amplitude, Frequency, and Decay. By adjusting these settings you can get a ton of different looks. We’ll get into those in some of the other examples, but for now let’s take a look at how the animation looks with the expression applied. You can see the bounce in all the properties and its on it’s way to being beautiful.
So let’s go over a few examples. In this first example there are three circles and they all have the same scale keyframes. The only difference is the settings for Amplitude, Frequency, and Decay. The first circle is the default values, The second has increased amplitude and decreased decay. The third circle has increased amplitude and frequency, plus decreased decay. Looking at these three circles you can start to understand what each of these properties does. Amplitude affects the amount of overshoot and bounce back. Higher amplitude means greater amounts of bounce. Frequency is how quickly the bounces happen. Higher frequency means quicker bounces. Decay is how quickly they subside. Higher decay means it will subside faster.
In the second example I have a five squares with similar position keyframes offset in time. They all look to the physics adjustment so if I decide I want to change the settings all I need to do is change it in the physics adjustment layer. The third example is a pendulum. So here the EZ Inertia has been applied to the rotation and the amplitude has been turned way up and the decay and frequency have been turned way down.
In this fourth example there’s a chat bubble being animated in with rotation and scale. Let’s walk through this one from start to finish. So I’ll select the chat bubble, check scale and rotation in EZ Inertia, and then hit clear. I’ll also get rid of the keyframes that are on it, and then I’ll delete the physics adjustment layer. Okay so at frame 7 I’ll set keyframes for scale and rotation at 100% and 0 degrees, respectively. Then I’ll go to frame 0 and change those values to 0% for scale and -90 degrees for rotation. With the chat bubble selected I’ll check the scale and rotation boxes and then hit Apply. That’s all there is too it. If you want to tweak this further you can always go into the physics adjustment layer and have at it.
In the last example there’s a car coming to a stop. You can see how as it comes to a stop the body of the vehicle relaxes and has a little bounce. So let’s recreate this one too. I’ll clear the expression from the rotation of the car body and delete the keyframes. You’ll see that I have the body of the car separated from the wheels since I don’t want the wheels to rotate the same way the body is. All of the parts of the car are parented to a null object which I’m using to move the car. I’ll go ahead and delete those position keyframes too. Okay, so at frame 23 I’ll set a keyframe for the car body’s rotation for 0 degrees. At frame 20 I’ll set a keyframe for the position of the null in the center of the screen. I’ll also change the car body rotation to 1.5 degrees. Then I’ll move to frame 0 and move the position of the null off screen so that the car isn’t visible at the beginning. I’ll also set the rotation of the car body back to 0 degrees. I’ll highlight both keyframes at frame 20 and apply an easy ease. With both still highlighted, I’ll right click on one them and go to Keyframe Velocity. I’ll set the incoming velocity to 100%. Previewing now, it doesn’t look too bad but if we add some bounce to the rotation of the car body it will really bring it to life. So I’ll check the rotation and apply it to the car body. In the physics adjustment I’ll bring the amplitude up to 4 and the decay down to 4. That’ll do it for the car.
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