The Power of Precomps in After Effects

Joey Korenman : What's up Joey here at School of Motion, bringing you day 15 of the 30 days of after effects. Today, I'm going to talk about pre comps. Now, if you've used after effects for more than a week, you probably know about pre composing, but in this lesson, I want to reinforce the power of pre comps. And a good way of doing that I found is to show just how quickly you can build very, very complex animations. That really don't take that much work. And don't have very many key frames, but actually look really cool and complicated. I'm hoping that along the way, you're going to pick up some tricks about working with pre comps. Now don't forget to sign up for a free student account, so you can grab the project files from this lesson, as well as assets from any other lesson on school emotion. Now let's hop in and make something cool.
Joey Korenman : So let's talk about pre comps. Um, and one thing I wanted to say about pre comps is that when I was starting out with after effects, they sort of freaked me out because you know, you do all this work and then you, you pre-com it. And all of a sudden you can't see your work anymore. And it feels like you're hiding key frames from yourself. And God forbid, you want to go in and tweak something. Now it's kind of hidden and it's, it's kind of, it makes it trickier. Um, and you have to manage it. Um, this is actually something after effects artists have been complaining about for years is the fact that you can't sort of see your key frames while they're in a pre-camp, um, very easily anyway. So, um, what I want to show you is some of the really, really, really cool things you can do with pre comps.
Joey Korenman : Um, this is a little bit more of a beginner tutorial, but, uh, I'm just going to keep pushing and pushing and pushing the pre comps until you get something that looks really, really complicated like this. Um, and hopefully what I'll show you guys is that this is actually really easy to make. Um, it it's, it's shockingly easy. So, uh, all right, so let's just hop in and get started and let's talk about pre-com. So I'm going to make a comp a 1920 by 10 80. All right. And I'm just going to call this square. Okay. Um, all right. So first thing I want to do is just animate something really simple. All right. I'm going to turn on my guides here by hitting the apostrophe so I can kind of make sure I have things in the center where they need to be, and I'm just going to make a square.
Joey Korenman : So a, an easy way to make a square and make sure it's in the middle of your comp is go to, uh, go to your shape layer tool here, grab a rectangle tool and just double click that button. And what that'll do is it'll make a shape layer that's right in the middle of your comp. Um, and then you can come into the shape layer settings here and Turrell open the rectangle and the rectangle path, and then you can unlock this size property. So the width and the height aren't linked anymore, and just make the width and the height the same. And then you can scale that down. And now you have a perfect square, right in the middle of your comp. You can do the same thing with a circle too. It's pretty useful. Make sure that, um, you know, if you rotate this thing, are you doing anything to it?
Joey Korenman : It's right in the middle. Um, and what I want to do, let me rename this square and I don't want to fill on it. Uh, I do want a stroke. So what I'm going to do is maybe it had like a, a two pixel stroke. And I think I had some nice kind of pink color in there. So, so let's get rid of the fill a quick way to do that. As you can click on the word fill, if you have this selected, uh, it brings up this little box and then you can just hit this guy and now it gets rid of the fill. It's kind of a neat little shortcut. Okay. So now we have our square and let's just do a simple little animation with it. Okay. So, um, you know, here's a simple thing. We'll have it start scaled at zero and then we'll go forward, you know, a second and we'll have it go up to 100.