Streamlining with Parenting and Null Objects

The way the animation is supposed to work. The background, the two photos and the text layers to slide to the left all at once. Now is the problem with what I just said.

Smoke, by the way, does not slide. Smoke stays where it is. But those four layers slide all at once.

Now, based on what we've done up to this point, you could do that by manually adding keyframes for each layer. Now, it's possible, but it's annoying. So, effectively, to slide it, if I put keyframes on each layer, that's four layers, two keyframes each before and after, that's eight keyframes.

Now, it's not a problem to make those eight keyframes, but if you wanted to modify it later, you had to change all eight keyframes. That's annoying. Okay.

So, there is another option. There is a concept in this program called parenting, which allows you to assign layers to be the children of another layer. When the parent moves, rotates or scales, the children do the same thing exactly.

Now, they do it relatively, like puppet strings, effectively. So, if the parent is like 100 pixels to the right, the children will stay 100 pixels to the right. So, just keep that relative change.

Okay. That's the idea behind it. Okay.

Now, technically, any layer can be a parent. Again, I'm going to hide these properties again because they're in my way. And, in fact, it's what that column is for, parent and link.

Okay. Parent and link basically allows you to assign any layer, using this menu, to be the parent of the layers you see here. Okay.

Now, so, any layer could be the parent. But, so, I could import a layer and use it as a parent. I could make a solid shape layer here and use it as a parent, a text layer, anything.

But, I would like to make a new layer to use as the parent for all four of these. And, I would like that layer to be invisible. So, you don't see it.

It doesn't get in the way. If I draw a rectangle, I've got a rectangle. I've got to hide it.

It's annoying. Okay. So, we have a special kind of layer that you really only see in certain programs like this.

It's called a null object layer. Its entire job is literally pretty much what we're going to use it for. Okay.

It is, when you export the file, it is invisible. In the program, it shows up as a little round, little box. But, when you export, they're invisible.

They have no physical appearance when they're exported. Okay. And, their only job is basically this, to be helpers, to be the parent of other layers so that you can basically move things around like this.

Okay. Layer, new, null object is the command. It's got a keyboard shortcut that I never remember.

Okay. And, like I said, when I make this, it's called null one. It is a little red.

By the way, it's red because the label color is red. If I change the label color to peach, it's a peach color. Rectangle.

It has the same transform properties that any visual layer does, except when I export. And, when I preview, by the way, a space bar, it's hidden. So, it has no physical appearance outside of the timeline, like at all.

Okay. I don't know why, but they make its anchor point in the upper left-hand corner. I mean, that doesn't affect anything.

It's just where they put the anchor point. Okay. I'm going to rename this one something that defines what it's going to do.

It's called controller in the instructions. Because it's going to control stuff. It's just a name.

Whatever you name it is fine. Okay. And, what I'm going to do is make photo one,  photo one, photo two, the text layer, rock and guitar picks, and the background.

I'm going to pick it as the parent. Okay. So, I'll highlight photo one.

I'm holding down command, by the way. Photo one and photo two, rock and guitar picks and background. On Windows, I would hold down control so I can select layers individually without setting everything in between them.

Because the smoke is not supposed to be part of this. Okay. Those four layers are what it tells you in the instructions.

The order you select them is irrelevant. And, from the parent and link column, menu, assign controller to all four. If you don't want to select them all, do it one at a time.

Same difference. As long as controller is in that menu, we're good. Okay.

If you want a little more fun than picking from a menu,  this little spiral to the left of the menu, if you drag it to the layer you want to assign as the parent, it assigns the menu. It's called a pick whip. Okay.

You just assign something. It's like the drop down menu does the same thing. Okay.

So, now the controller is in charge. So, when the controller moves, they all move. When the controller scales, they all scale.

When the controller rotates, they all rotate. The controller is in charge. Except the one thing the controller does not control is opacity.

Changing the opacity of the parent layer has no effect on the children. So, opacity is the one property not inherited. Okay.

So, the instructions have you. Why did my book close? It is so weird. Creating a null object layer.

Done. Assigning the parents. Animating multiple layers of parenting.

Okay. So, I made the null. I assigned it to be the parent of the layer.

So, the children pick the parent. That's how this works. Okay.

And then I can animate the controller. It wants from six seconds. I'm going to animate the position.

I'll turn on the stopwatch right in properties. It reveals it right here in the timeline. Or I could have pressed P on my keyboard to reveal position and then click on the stopwatch here.

Same difference. Okay. And at seven seconds, they're going to go this way.

The instructions tell you that I use negative 900. Whatever. Okay.

So, if I hover over that number, I'm going to hold down shift and I'm going to drag it until everything slides off screen. What I did when I built this is I basically did that. Oh, that looks like good.

What was the number? Probably like negative 870. Let's do negative 900. Nice round number.

I swear that's all I did. Okay. So, if I put it exactly negative 900, it's fine.

But again, it was just when it's off screen. You're never going to know the exact number to use. You're going to scrub, adjust, move things around physically.

And then if you like round numbers,  maybe you'll set it to a round number. Okay. Whatever.

So, now here's what I got. I've got my audio muted because I really don't want to hear it. Smoke blows in.

Photo falls down. Second photo falls down. More smoke.

And then everything slides that way. Okay. So, instead of having to make two keyframes for each layer, I made one keyframe for parent.

Everything follows it. And that's the key. If I then decide to select both these keyframes and add a little easing, right click, keyframe assistant, easy ease.

Instead of having to do that to eight keyframes, I did it to two. Okay. If I want to make that faster, I can pull the second keyframe closer, slower, pull it further apart.

Instead of having to do that to eight keyframes,  I can do it to two. So, when animating multiple layers simultaneously, parenting is extremely,  extremely convenient. Okay.

If you're familiar with the program, you may be familiar with a concept called, oh God, my brain is breaking, pre-comping, pre-comps, which basically take layers and turn them into their own compositions and animate that as a group. Parenting is an alternative to that approach. And the main difference is that if I pre-comp that, they would stop listing as individual layers here.

They would be consigned to one layer, which means certain things I want, like blending modes, wouldn't work anymore. And the fact that they're separated through layers in between wouldn't work anymore. So, this is an alternative that preserves the layer structure.

And that is the two parts on the end of 2a. There is a big informational section on page 45 that explains the concept of parent and child layers. Okay.

And there's a whole bunch of things. And it explains a couple of things of where you would do it. Like, another example of parenting is if you had a car animation, the wheels,  which would be separate, so they rotate separately, need to move when the car moves.

So, the wheels would be the children of the car layer. Okay. That's the example they have at the end of that to talk about it.

So, it's a way of controlling multiple layers simultaneously to allow them to move, transform simultaneously. It's a very common feature in animation. Okay.

Kind of cool.