12 Principles of Animation in After Effects

In this lesson, we're going to learn how to apply the principle of squash and stretch in two animations. So the principle of squash and stretch is all about how objects move in the real world. Objects with volume tend to distort or change shape depending on how fast they're moving and what is happening with them. So here in Ball Bounce Start, you can see we have this ball falling and then hitting the ground. Now, of course, this looks very unrealistic with our current settings. But how can we increase the realism and make this much more appealing? Well, the answer is we can squash and stretch this ball. Now there's two very important parts of squash and stretch. One is maintaining volume. So we want to make sure that when we squash and stretch this ball-- I'm just going to hit the S key-- we do not change the size or the amount of volume that this ball has. So we want the volume, or the amount of space this takes up to stay consistent. Now on the other hand, squash and stretch also helps us show elasticity or density of an object. So squash and stretch is about scaling and distorting. In this case, let's take a look at scaling. So here we have a ball falling and then hitting the ground. Now even with motion blur on, this doesn't look like it's falling very fast. Even though it is translating over only, let's say, three key frames. It's an incredibly fast movement. So to create the illusion of speed we can stretch out an object. So to do that, we need to make the width of the object smaller along its direction of motion and then make the length of the object longer. Now in this case, I made this object to have this be very easy with the scale. But depending on your anchor point position, this may or may not be as easy as it looks here. So to stretch something out in this case we want to increase its height and decrease its width, or increase its scale y and decrease its scale x. You can see here that now the ball looks elongated as though it is traveling much faster than it actually is. So here we can see that. Now, of course, we're going to need to key frame this effect off as soon as it hits. So let's go back to our scale, key frame this on, the frame right before it hits and jumps forward one frame, and reset these back to 100. So let's take a look at how this-- so we can see now the ball looks like it's traveling much faster. And we can continue exaggerating this to make it feel much, much faster. Let's make it longer. Make it a little bit thinner, and you can see that it looks like it's traveling much, much quicker. So depending on your settings, of course we need to maintain volume. And with the scales, this can be sometimes difficult, because going down from 100 and going out from 100 give us some different numbers. For example, if we want this to be twice as long, we would obviously put in 200. However, if we reduced x to zero, subtracting 100 of course we would have nothing. Instead, we need to say, OK, we doubled the height, so we need to take half of this other attribute. So let's put this at 50. And now we have volume maintained. This area here that this ball is taking up is the exact same it takes up and down here at the bottom. So you can see here if we overlay them together, we can see they take up roughly around the same space. Now, of course, motion blur is blurring this a little bit, but we can see that we have maintained volume during this action. So now let's add in the squash. So we'll go to where our scale is here and once it impacts, or once our object changes direction, we need to squash it. So in this case, I'm going to increase the width by 200% and decrease the height to 50. And then a few frames later, we can have it bounce back to 100 and 100. And what this does is it gives us a really nice transition from stretched to squashed. So you can see this impact feels much more natural because we are having the ball deform based on its volume, based on its density, and based on its changes in direction. OK. Great. Now of course, you can come in here, change the timing, make things appear as if they are much denser. So something like a bowling ball would only stretch for single frame, and then it would bounce back into place. So you can see that seems like a much denser object. While something like elastic would hit and then stay stretched out. And of course, we can also add follow-through to this. So we can reverse the stretch here. So let's pull this out a little. And let's take a look here. And we can of course flip this over so that it is now squashed a little bit and then stretched out. So it's kind of bouncing in between those two states. So if we take a look at this, you can see we make this look much more elastic depending on how much follow-through or how many layers of squash and stretch we place on this object. Now let's take a look at this in a more real world scenario. If you want to continue this, you can. There's a few small issues we have with motion blur. But you could look into comps, Bounce Ball Complete, where we've gone in and animated it to finish. OK. So now, let's jump over to main comp start. So we have this text coming in. And what I would like to do is I would like to apply our squash and stretch to this text and have it be a little bit more of a dramatic change. So while the tight deadlines come together, I want them to stretch upwards and as they're-- excuse me, squash upwards and downwards-- and as they are being pulled apart, I want them to stretch out. So to simplify this I'm just going to create a new null. Both of these have different anchor point positions as well as different scales. You'll notice the anchor point is over here. So let's create a new null. Let's parent both of these objects to the null, and I like using nulls for this. It makes things a little bit simpler. And let's go to our scale. And so here at the end, we want it to be squashed. So let's manipulate this, so the X is in a little bit. And the Y is up quite a bit more. And then set a key frame, and at the beginning, let's reverse this. So at the beginning, let's have it be really stretched out and really tiny. And what we get is this transition here. So see that by squashing and stretching this, we are sort of accentuating the tightness of these deadlines. Now this beginning here might be a little bit much. So I'm just going to stretch it out a little bit less. Let's take a look at this. There we go. OK, great. So what we've been able to do is we've been able to add a little bit of squash and stretch to this text to give it a little bit more dynamic feel. And to sort of accentuate and exaggerate the coming together and the squeezing of these tight deadlines. So you can see you can use squash and stretch with text, with titles, with all sorts of things. And so the main two uses I use it for is when an object changes direction or changes motion, adding a little bit of stretch or a little bit of distorting helps show that object has elasticity and isn't unreal or made of bowling ball material. And it also helps us exaggerate or keep the volume of things. If we had just done this without any squash and stretch, if we had kept this the same, we would have a very strange motion here, because it would look like the volume or this starts out larger and then gets smaller. So again, use squash and stretch to accentuate volume or to maintain volume as well as to add a nice little touch to motion.