Tracking Rotation and Scale
let's get a little bit more advance. Take our fares wheel clip, drag it into the new composition button and now let's just select the part where we want to track. So we're just going to go until the ferris wheel is almost out of the frame, right? We can go after the ferris wheels out of the frame. Actually that's fine. Go right there and then for the beginning let's just start around five seconds that will work. Take the end dragon trim comp to work area now in our tracker, click track motion. Okay you can see that this video clip is a lot more complicated than the other one. First the background isn't a clean blue sky, there's lots going and then the camera's moving so we're moving in space. Things are getting larger so that's going to affect how we're tracking and that's why we have scale and there might even be some subtle rotation of the camera. It looks pretty clean but it's hard to see from you know, the naked human eye. Let me just show you what not to do. So if I zoom in and le...
t's zoom in just a little bit. Let's take our trackpoint. Let me just put it say I want to track the middle of this ferris wheel right there. Now let's zoom out and let's just analyze. Okay that actually did a very decent job of tracking that middle point. I thought it wasn't going to do is get a job but you'll notice. Now let's actually create our new null object layer, new null. Let's edit our target to make sure it's The whole object 10. That's good and then click apply X. And Y. Yes. Now let's just add some text. We'll just say movie title and let's just change this to Helvetica Standard and make it bold so we can see it a little bit better. Let's also so at a stroke. So just by clicking this stroke pixels to the right and if you want to change the color of the stroke just swap this fill stroke over here if you want click the stroke color and we can change it to really any color we want. But I'm going to leave it at black now let's go we're at the start. So let me put this right here at the front let me attach it to the null object then let's play. So that doesn't look that good to be honest. So it works but it doesn't look like it's actually in the space of the video and I want this title to actually look like it's sitting right there in front of the ferris wheel. And the reason why it doesn't do that is because it's not affecting the scale of it, it's staying the same size here and here before it goes out of frame. So that's why what we want to do when we're tracking motion like this. We want to make sure that we have the rotation and scale selected. So let me just turn off the title right now and I can leave that null object or I can delete it. I'll just delete it now. If I click ferris wheel, let me just click track motion again. Alright so let me zoom in To 100%. We can put this back on the middle of our ferris wheel. I'm going to make the box just a little bit bigger so it has a little bit more detail and then I'm going to click rotation and scale. You'll notice that what happened when I clicked either one of those, is that a track or two popped up? I know it's hard for you to see there's lots of detail here But we have tracker .1 that I said and then tracker . When I click and Drag This, there's this line that's attached to the track .1. The way this works is that by tracking two points in your video after effects is able to track both rotation and scale because it's seeing what's happening between those two points comparing those two points to each other. So what I found that works well is if we want to have this text or layer within your video clip and your cameras moving. I like to find two points that are in relatively the same same plane of field so the same distance from the camera. So I'm not going to pick something in the background like this building right there unless I want to put my text back in the building and track the motion of the building. Then I would put both points back there and add my text back there. But if I want to put the text right in front of this ferris wheel, I'm going to track the motion of this ferris wheel and then maybe let's find something else that has a lot of sort of contrast. This car right here has a lot of contrast. See that car, it's white, there's dark, there's also some green. So that helps with another kind of brightness. And then let's zoom back out. So now when I analyze this and let me actually go ahead and just click and add a neutral object. Usually I like adding the new null object beforehand. It doesn't really matter. But when I click edit target now it's selecting the movie title. I want to make sure it's on the knoll. 11. Okay, let's analyze. So it's analyzing both points. It seems like it's doing a relatively good job. Now you'll notice right then, Oops, okay, right there too. Once this car was out of the video frame, it stopped working the tracker point just stuck at the bottom of the frame and then right here, right when that middle of the ferris wheel is out of frame, it just sticks at the bottom of the frame too. And that's just because aftereffects does not know what to do at that point it's out of the frame. It doesn't know where to track. So all of these track points after those are out of the frame are kind of worthless and I'll show you why in just a second. So now let me turn on my movie title, go back to our composition. Actually, let's go into our layer. Make sure we apply this tracker to our target so click apply both X and Y. Yes. Okay, so now we're back in our composition. Let's parent our movie title to Noel 11. Let's make it a little bit smaller. So I'm just going to go into the character, make it a little bit smaller and we'll just set it right sort of in front of the first we're like, so maybe just kind of hovering in this sort of open field area. Now when we play through it it actually gets bigger as the camera gets closer. But look what happened after that point. So after that car leaves the frame that we were trying to track, whoops, this goes haywire. Okay, so what we're going to have to do is manually adjust these things or if we want we can move this title closer to us. So if we move it closer, stay right there and then we play through, it's going to be off the frame by the time that this car right here is off the frame. So now it should be fine. But after that it goes haywire. So we'll make sure that we clip this clip of the text to this point. So after that it's gone for good. So that's pretty good. Right? So there's two different ways you can do that. You can move the text up but say we don't want to do that. Say we want the text to be sort of back closer to those cars like So then what do we do while at this point right here, when it goes haywire and I can start to see it go haywire right here. What I'll do is go into the null object, press you to bring up the key frames And see we have key frames for position, scale and rotation and just so you know that the scale is increasing here, it's at 100% here. It's almost at 200%. So it really is growing, wow, the camera is moving over it. So here it is. All right, there is where it goes haywire. So what I'll do is just delete all these key frames up to that point. So I'm dragging over all of them and deleting them and then what I'm going to have to do is frame by frame or sometimes you can just go like a few frames ahead until you think it would be off camera and move it down with position. So if I just zoom in here really close so that moved too fast. So I'm going to extend this And you can see it starts to get smaller, which I don't want. So here, I'm also going to set a key frame for just a little bit bigger. Maybe like 200%. That's pretty good. Maybe a little bit bigger. 12 5. Okay, that looks pretty good. So you can see that. I don't necessarily have to add key frames for every position to get that motion. Now, one thing you might notice as you work on your own projects is that there might be some subtle little movements that you don't like. Now there's a couple of things you can do, you could either try re tracking the motion to see if you can get a cleaner motion or you can go into the individual key frames and fix it. Or sometimes deleting key frames works. So sometimes as I'm going through this, I might see that there was one little spot where it jumped to the left a little bit. Maybe just delete that key frame now. Say I wanted a title back here in the buildings in the background or maybe I decide, oh, I actually want this movie title just to be up here and I wanted to kind of move with the building. Well when I do that and I play through, it doesn't look that good because it looks like this title is in the plane of the ferris wheel. It's not growing at the same rate, it's growing faster than the buildings are growing in size in the background. So if you want to move your title, make sure that you're tracking points in this space where you want that title to be. Does that make sense? I hope it does. If not just ask me any questions in the Q and a tab of the course. So let's put this back here in the next lesson. What I'm going to be doing is adding that shadow and making this look a little bit more real. But hopefully you've enjoyed this lesson now, you know how to use the tracker to track both position, rotation and scale.