4.3 Spatial Interpolation

In this lesson you are going to learn about spatial interpolation. I'm gonna pick up right where we left off in the last lesson. And I'm going to take my top layer here, the one where we were experimenting with the easing of the keyframes, and I'm gonna just get rid of it. And I'm gonna take this text layer, I'm going to click on Position to select all of the position keyframes, and I'm gonna position it just about in the center vertically. If you select your layer here you can see there are a collection of dots between these two points. If you put the CTI right in the middle of the animation, you can see this represents the starting keyframe. And this dot here represents the ending keyframe. And each one of these dots represents a frame, That the layer is going to be on at any point in time during this animation. Right now, these dots go in a straight line. And so when you're talking about the space or the path that it's taking, it's going in a straight line, so this is called Linear Spatial Interpolation, right? From point A to point B it take a straight line. So in terms of the space that the object is covering it's linear. But what if you didn't want this? What if you wanted the K to start here and stop here but maybe you didn't want it to go in a line, maybe you wanted it to go in an arc, up here. Would that mean somewhere in the middle we just add another keyframe? Well, no, because look, now, what we have a starting keyframe, and then we have a middle keyframe, but between those we have another line. So we could go again in the middle, and kind of make this into an arc, but that is kind of annoying. Plus, that would make it a little bit trickier to ease this animation if you wanted to. So let me show you another way, I'm just gonna delete this middle keyframes here. So if you have your key frames selected here and you right-click on them, you can go up in the little pop up menu and choose keyframe interpolation. And there'll be a little dialogue box that comes up here and you have some options. So you can see temporal interpolation which affects how property changes over time in a timeline that's set to linear, but you can choose some different options here. Spatial interpolation affects the shape of the path which is the motion path in this case because our object is moving. And if you click the drop-down here we have some options. We can set it to Linear which it is set to currently or we can set it to Bezier, Continuous Bezier, or Auto Bezier. Let's select Bezier, and then click OK. What we get now is we get a set of handles on our first keyframe and on the second keyframe here. So let's click on the first keyframe. And you can click and you can drag this handle, and you can make a curve. So now, you can have your object not take a straight line between two points, you can have it take a curve. And with these handles, you can get really specific on where you want this K to go. Let's just play this and see what's happening. Check that out. You could even set these in different directions and make kind of an S shape, if you will. You can drag this way out here. Sometimes it can be helpful to, Make the comp smaller so you can drag these handles out. All right, let's see what we have here. It's still only two key frames. But with these handles here and with the spatial interpolation set to Bezuer, now I have a lot more options. Now, there's a couple of different ways that you can enable this, you can right-click on the keyframes like we did before and go to keyframe interpolation and set it to Bezier. You can also, with the selection tool selected. If you hover over one of these keyframes, you can use keyboard modifiers. Ctrl+Alt, which for some reason are not coming on my key display here. But when you do that, you see, you get this little V tool, which you may have seen before in the Pen Tool options over here, and that is a convert vertex tool. And what that does is it would change this vertex text here from right now it's on Bezier. But if I click this with Ctrl+Alt held on my keyboard, it will convert this point back to a linear point. So now, this one is linear and this one still has the Bezier handle. But if I wanted to convert that one back to Bezier, no problem. With the selection tool, I can use Ctrl+Alt on the keyboard, or we can grab the pen tool and choose the convert vertex tool. And you can click it and it will become linear once again To go further, you could maybe set one more keyframe here in the middle, maybe just pulling it up like this. And then, We can convert this to a Bezier handled with the selection tool using Ctrl+Alt and that will give us this nice Bezier handle. Which this is a continuous Bezier, meaning that the handles move in tandem and you could make something like this. Maybe make some kind of loop here. It doesn't look spectacular, but I think you get the idea. If you hit Ctrl+Alt again you can grab one side of these handles. And this is called a bezier, where each side of this point has its own independently controllable handle and they're not linked together, or it's not doing a continuous curve. You're kind of breaking it here. And now you can do something even more intricate. So you can see it comes up here. We have a really sharp movement. So you have a lot of options when you're animating. Sometimes, you just wanted to go on a straight line but other times, you want things to go along a curve and doing that is a lot simpler than you would think. And you can do it with only a few key frames. Just like that. And on top of this you can also smooth out the temporal interpolation. So I can select my keyframes here I can hit F9, which if you remember is easy ease, which will do a very slight ease out of the first keyframe and ease into the second one. Or you can hop into the Graph Editor here. And make it even smoother. And that's just with two keyframes. Now, that you understand the basics of spacial interpolation, you're ready to move on to the next lesson, where you're gonna learn about masks.