Motion Tracking Basics
So right here, I want to label this footage and this is unstable eyes footage sometimes you still have to track something that is unstable ized and sometimes that's actually a little more impressive to see uh, text floating over something that's moving, you see that a lot in commercials and on tv and, uh, maybe it's the labeling something you'll see a commercial, somebody walking down the street and you see, the label will follow them along and ah, that's a pretty easy technique to do here, right in after effects. So what I want to do is have this label show up right when I get to the golden gate bridge it's just labeling the golden gate bridge. So how I do that? Yes, I've just got, you know, these two layers are in here, I've got to that already done, so if way have to, you jump ahead, we can, but I want to track the golden gate bridge, so right, when I first see it coming on right about there that's what I want to start my tracking. So I come over here to my tracker panel and I click...
right here, says track motion and that gives me this little track point out here in the middle and I'll zoom in a little bit on that and we'll see when I click on it I've got two boxes that got an inter box in an outer box. The first thing you do is going to stretch out this outer box a little and then stretch out big box because in most cases, the item I'm trying to track is bigger than the default a little box and then I just drag it over and he's a metal hand tool there turned on it mouse pose a so you can see what I'm hitting there. There we go hand tool move stands around, okay? And then I want to track the top of the golden gate bridge here and in this tool, you'll notice you can't track outside the box you can lay track are outside the window. Um, this inside tracking box here only allows you to go to the edge that's why you have to wait till something's fully on screen here. Okay, so this outer box basically says this is the area you want to track right in here and you look for something with high contrast and as much clarity is you can the higher the contrast, the easier it is going to be for it to track. So find a nice, sharp edge, find a point, find a corner of something, something that doesn't change throughout, uh, that part of your motion and this outer box just says track that, but you can look outside in this range you don't have to look over the whole picture, but just look over this part of this range. So as things move, it just keeps searching within this outer box for moving pixels from one frame to another, so I come down here to the analyze area and I just click this analyze forward button and let it analyze and I can stop that can move it over so I can watch it a little closer. I the reason why I couldn't do it in segments like this because if it sees a stray pixel or bird flies through it or something, sometimes it yeah, it goes off another direction it's important to be ableto back up, fix it and then move forward so I stop it move over a little started back up again and it won't show me key frames until I stop again, so don't worry about that. You just watch the little box move and then more right there, okay, so that's my range of tracking I have to be done with whatever I'm tracking by that point or I have to fake it later with your positioning and then you then you're doing what we call match moving and you're kind of guessing and they're still going to be some of that going on when you're doing motion tracking anyway. Okay, so now what I want to do is I've got these tracking points in here it's done a nice job of following that I have to, uh attach those to something so I want to edit the target that it's going to and I know it's this layer uh golden gate bridge too because it's the second golden gate bridge text that I have in the scenes I click okay and then I click apply and yes, I wanted to apply to both x and y dimensions that's because we're in too dehere and there it is it is attached although because our anchor point was uh left justified it attached the anchor point right at the edge of our text there it's right at the edge of that corner that g so real easy to fix you always have to end up moving your anchor points when you're tracking because you know one thing or another something doesn't work so remember how we moved our anchor points it just click and drag on the numbers they raise it above a little on dh now the bridge is their notice before it gets there it's stuck in that first position so what I would typically do here I could either fake it uh and drag it off to the right where I think it will be so it looks like it's just a few pixels above there so what I could do iss click and drag it off here about so guessing and that would fake it in it's. Probably moving a little more than I wanted to. Okay, that's. One way to deal with it. Or I could just fade it in as it comes on screen. So I know it's. Um, not really on screen yet until we get to that point where it starts tracking. So come in just a few frames, my capacity come back here and past zero. Okay, so now it just fades in while the text comes in. Now I would do the same on the other side. I'd faded out as it goes out, so you can see that it isthe doing a nice job of just tracking the golden gate bridge that nice? Uh, it's not turning in three d space that's. Something else that I could do, but I would have to fake its rotation to do that if I did it as a three d layer again, that goes a little deeper into more, uh, more territory than we have time for this morning. So but that's, just a really easy and easy way to track something that's in your video footage. Now, if I had stabilized the footage first, then brought that in and then tracked it, of course, it would be a really smooth you know move but sometimes it's kind of cool to see stuff you know track something really crazy and I'm going to show that is a with the three d tracker here in just a bit yes you have a question? Uh, yes I uh was working runs in the project where we had to track boat the graphics on um the problem iwas that may be the color of the water the color of the boat kind of similar to the edge was not clear. So capital is in the like there's just the body and then the hide of them the length of the hall so what we want the editor did wass doing it manually but I think it took about five hours oh, yeah, teo like because it would go somewhere else and then come on, bring it back. Is there a better way to name me? Well, there's there's different ways if you're if you're trying to track something probably something in that case there's two or three things I would try I would try you know, the roto brush which we're going to cover later today try that that's not perfect either, but it might get a good start um uh doing it manually you say with spine tools mean that's going to take time obviously, then there's another way of doing shapes inside of mocha I'm gonna introduce you tomoka here in this exercise so mocha is another application the evenings for tracking making mats and things and what it does is a plainer tracker so it works a little bit differently so that's actually I did not pay you to ask me that question so it's funny that we're kind of getting to there I'm not going to be showing that type of that type of a track or matt creation, but I am going to show you how to use mocha to, uh to do your motion tracking so that's actually it's it's kind of funny so what I've got here is uh two layers I've got this video footage layer here see that's there okay, it worked it just needed to reboot after effects there some reason on then I've got this cool license plate that I made for creative live and I don't know if somebody actually has that but that's that's our so I made that and I don't think they use aerial rounded on license plates anyway, but I just I had fun had to make a license plate for this. I think what I want to do is take this video footage here and replace that license plate that's on that car system stock video footage I got and I've got this license plate that I want to replace that with so an easy way to do that and I think it's easy because uh mocha makes it easy for us so what I want to do for tracking this I don't use the tracker inside of aftereffects they used the tracker in moca what I have to do is select the movie that I want to track on my timeline I right click on it and I go to actually I don't right click on I think it'll probably be easier to come up here to the effects so I'm going to effect and then um boy now I'm trying to remember is it a simulation? Is it um I just got my train of thought just got derailed by the video not working it isthe um perspective no like tracking it's not keen it's well, let me take the spotlight off for a second here. Um hold on just a second. I know it's over here in animation no wonder that's where it is I'm trying to think what things got moved to effects and where did other things get moved? Because this is a little different workflow that used to be so now here it is it's over here I had to stop and think for a second. So are an animation and then track in moca e and that launches the mocha application mocha for eh application and I don't need this information right now already registered thanks um no, just leave everything alone and this is the clip that I had selected it automatically saw that it sees everything in here, and I'm going to just leave everything on its default because it sucked in all that information for me, so it already fixed figured out the pixel aspect ratio figured out the frame rate, how many frames it wass they just sucked in all the information because I was already in aftereffects, so yeah, go ahead and override it because I did it before there we go. Okay, so one thing that's a little bit funny with this is as it's computation ing computation as it's doing its computational efforts, it tends to make this window bounced around a bit, so let me see if I can shrink it so it doesn't totally drive everyone nuts. I was able to do this on my laptop, and it worked a little bit, so let me me try see if this will shrink just a little bit more. Yes, if that helps out now we'll see it may bounce the window around while it's thinking so, uh, just giving you a heads up on that. So this is a very big, scary, complex piece of software, and I I don't want to scare you at all with this, so I'm just going to show you one or two steps. To make this particular project work well and there's some great moka training out there already all over for free out there in the internet and you can find out just by going teo imagines just google imagineer systems or mocha and there's crazy and fought there there's bigger versions of this to kind of like with cinema for delight there's bigger cinema forty package same thing with mocha but for this work flow this is just the quick and easy way of making this particular thing work so what I'm doing is I'm grabbing this uh icon here is just to create an ex ex plein create explain layer tulle and I want to come out just a ways away from this license plate this on here, so click and then click click, click and it doesn't have to be perfect because I'm just trying to track that bit of information as it moves across the screen so I've got that set make sure they're wide enough because if it moves around then it'll track it and now what I do is I come over here to the track forward button kind of work similar to their you know the way that the motion tracker and after effects work so I just click that to track forward and it's making the thing bounce a bit I'm not sure why does that something funky uh with this particular version so not sure why but it's thinking about every key frame and doing a little dance maybe you should play some music for us while it's doing that okay so we're letting it think let me think let me think and it's jumping that's crazy I've never seen anything do that before it's really bizarre yes mocha tracker um s o confucius jones asks why is the tracker in moca preferable to the one that comes standard with after effects? Okay we're going to see that in just a second here. Okay, so what moka does is instead of looking at a um you know defined pixel area like a like a sharp edge or arrange it looks at a plane it looks at a field of pixels that move so if you've got something if you get the side of a car even the sight of a face uh you know anything that's plainer in the three d world it's going to look at that so if I took like this piece of paper and I was just moving it like this in this direction or this dimension you know any tracker could probably pick up on that because it's confined edges but if I start doing this to it or anything like that or bring it this way than trackers will only find an edge and you know it's like even at the golden gate bridge I was panning across but the bridge, you know, was actually doing this but my text was doing this is it was tracking across so if I had used a plainer tracker like, uh, mocha it would see that oh, the bridge is actually moving this way and it would force whatever layer I'm tracking to go with it to follow that curvature to follow that plane so being that mocha is a plane or tracker, it follows that plane and here's another thing that it does quite well see, I thought I saw jump here it wasn't before there toward the end it's hard to see because that whole thing was jumping there for a bit. So there it goes there there goes there that goes there notice how it's tracking even off right up to the point where it goes off the screen. Yeah that's not gonna happen after effects it's going toe make a collision there that's going to stop tracking right there. This will continue tracking causes. Oh, well, it's still moving some of the pixels in my plane are still moving. I'm going to keep tracking where I was and then it stops of course, thank you so that's going that's going on the plane now what I need to do is one last thing is to look and see, ok, where is the surface at now I can look at this and this will kind of show me a grid this little turn on that grid and it kind of shows me the surface of the tracking what's happening with it and I usually don't turn that unless I really see something jumping weird but this year the planer surface is where the corners are that I need to see um I'm going to set for my corner pinning for the the license plate I'm putting in so I want to look at this I'm scrolling uh what ideas? I grabbed this eyedropper here I didn't make that evident I just grabbed it without anything it zoom tool and grab that and you have to slide up and down click and slide, click and slide and that allows you to move it around in this tool you actually have to click the hand tool to pan around otherwise the space bar just starts playing, so I'm going to center that so I can see what I'm working on then I just grabbed a little pointer tool here and now I want to set these corner pins here because I know I've got a frame on my license plate I want to make sure I cover up this one so going to cover that up uh here here uh okay just won't make sure wide enough here to on this so I'm kind of framing the frame around the license plate just to make sure that one looks like the bottom of the frame is there so I don't want to make a too tall so that looks like it's pretty close two matching the frame on my license plate bringing down just a little bit. Okay, so now when I scrubbed through may zoom back out here and move it down now, when I scrubbed through this, I can see that that maintains that shape all the way through. Okay, so now I've created this I can go right to the next step of exporting the tracking data. I'm happy with the track. I'm happy with how everything's fitting in there and I come down here and I can click export tracking data and there's two things I can do I can save it as a file and it says, uh, save it as a text file that you can then import if you want to later any, uh, any point but I'm going to just copy this to the clipboard because it's really easy I just copy it. Then I go backto after effects and I make sure that my playback head is at zero on my timeline and I click on the license plate layer and then I just simply paste that's all I d'oh so now that license plate is going to track but it's not in the right place because I have to move my anchor point still so a for anchor point bring that into position here and that should track fairly cleanly through there till he gets to the end then it goes what right there and that's where I'd probably just end that layer is cut it off there let the truck go by so let's do a quick render and that's fairly clean so what I would do next to make that probably a little better since this layer is in motion I can use the motion blur here and let it try to copy that a bit helps smooth it out a little more and then if I wanted to since the camera isn't really focused on that car is focused right here it doesn't really come into focus till about here somewhere in here it looks like us where they did a pull focus right about here so this is where I would use like you oh maybe the lens blur camera lens blur probably used that um so that would obviously be set at zero at that point that's my outpoint let me get down here to my effects and a camera lens blur radio zero and it's like it's pretty much there so do my blue radius here now three so that comes into focus about the same time the car does so so how about that is that cool or what? Yeah, everyone in chat agrees as well. Every school. Wow, what a great, well, there's there's. So many things you could do with that. I've dunnit where I've replaced the side of a truck with another graphic, and then you can, you know, using different layering techniques in after effects, you can bring back reflections and things like that make it really believable. But, again, it's it's, how do you fake it? Has really, yeah, after effects is, uh, is the tool for fake and stuff. So it used to be that you couldn't believe a photo. Well, he's obviously can't believe videos now, either. So thanks. Tow after effects for for making our world of make believe so so that's, using mocha and that's a pretty cool tool.