Hi there, in this video we're going to look at something called Pre-comping. It's basically this grouping. What I would like to do is, I'm going to show you an example of why it would be awesome.

So what I'd like to do is, I'm going to twirl it down just to make it look nice. I'm going to zoom out a little bit. And what I'd like to do is, I'd like to get this Octopus to move around this animation. So I'll start at the beginning here. What I want to do is, grab the head. Say I want to move it down here, that's fine, I can move it down there. Then we're going to go and move the legs, right? So I grab the legs, I'm going to move it down. The trouble with this though, is that say, later on-- So, I've set my-- Actually I'm going to 'undo' twice. What I want to do is animate them both. So I'm going to set 'Position' key frames for both of them. So I'm going to set you, 'Position', and you, 'Position'. So they're both waiting for me to move them. It's him there, I'm going to go along to maybe 2 seconds, and down. And I grab the legs. Move it down. It's going to kind of work, watch this, comes down, he's doing it.

The problem is, I had to move them separately which is no big deal in this case, but say that I want to now move this head up here. And I want to get the legs to move as well. Whoops! I'm just going to grab anything here. And then I want to move him over here. Head, I have to pick that one, move it across. I'll have to spend this time moving all these objects and that's fine, no, it's not fine. It's double pain because we're trying to align them up perfectly every time. I've kind of winked it, and it's looked all right but it's not aligning up perfectly. And this means that if I had three things, say his eye was blinking, it was a separate animation, and he had bubbles coming out of him. The problem is, I'll have to move every single one of those every single time, and I'd be here forever. You can do it that way. I'm going to undo, so 'Edit', 'Undo' 'Undo', till I'm back to here.

So what I want to do is group them together. I've got these guys up, so I can group these guys together. I can move them along as a little unit. And it's called Pre-comping. To do it, I select you, and you. You need to drag a box around them all. Or click the first one, hold 'Shift', and grab the second one. And now I'll right click it. There's one called 'Pre-compose'. So if I pre-compose I can give this a name. This is going to be called my 'Octopus'. I'm going to click 'OK'. And now he's pre-comped. What's happened is, there's my Comp, this is the original one that I made. Just call it 'Comp1', you should name all of your layers. I never do, you should. Well I do, but unlike you, I probably forget. If you're a Photoshop user, and you've got hundreds of unnamed layers, I'm like you.

So I've got a 'Comp1', and this is the new one that I created. Remember, it's called pre-comp, it's a composition. It's just like a group, and it's wrapped that old self in there. If I go inside of this Octopus, 'double click', there's my little animation, originally, but If I go back to my comp, where I was, you can see, it's just one little layer now, nice little tiny group that I can animate. So what I can do is, I can say, I want to start you maybe there. And maybe I'll rotate you around, there's a 'Rotate' tool on the top here. And I click and drag anywhere. Go back to 'Move' tool, that's the one there.

So let's get into the beginning. So I'm going to go down here, say 'Transform', and go 'Position'. And then, maybe after about 3 seconds it's going to move across there. Actually what I might do is, 'undo'. I'm going to go back to the beginning. So I've only got one key frame. While I'm here, I might do one of the scale as well, so we start nice and big. When it gets along to about 3 seconds I'm going to move him up, and make him quite small, so I'm going to grab the scale, move it down. Still looks like it's kind of heading away, or something like that. All right, here it goes. Go do your little squidgy Octopus thing. Nice!

So you can see how easy it is that they're just one unit. And I could now bring it along, and maybe after 10 seconds get him to head over here, and be even smaller, so down to 0. He's moving in a weird way, here he goes, off to there. And he moves around, and slowly but surely, gets smaller, and smaller bye. And he goes along. So, that is pre-composing. You can do it with anything. If you got two-- It could be2, it could be 20, it could be 10,000. Does pre-compose them. I guess editing the Pre-comp is a big one. You just got one layer now. Say I want to change the way the squid is going in and out. I need to go inside of it.

You can do it a couple of ways, you can double click it. Watch this, if I double click it, couple of things happen, this changes at the top here and can you see here, there's my original Comp1. And there's my Octopus, so I've kind of gone inside of it. To get back, I need to go back to Comp1, or click on this tab here. It's up to you which way you want to work. Inside, I can go in here, and I can play around with my-- say it's my legs here, I can start twirling these down.

This is a cool thing, see these little black dots? These little black dots are your key frames further down. Because at the moment, we're at this one called ‘Transform’. So we're not at position yet, there they are. So these little black dots just indicate that somewhere down here there is some key frames, sort of a visual cue for you to say that down here, below, somewhere, there's a key frame. So I can pull down, there they are, awesome. I can decide to maybe speed this up or say I select all these guys now. I'll group them all even. Hold down 'Alt', and just drag him that way to speed him up. Oops, I don't want to just move them. That's working now. Cool. So I'm going to tie him down and lift him up. And then when you're finished, close that one down. Back to Comp1, and everything's been updated. Great! So that's how to do a Pre-comp.