Motion Tracking & Object Tracking inside Cinema 4D: Tracking a difficult feature of the object

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  • Duration: 13:30
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Learn how to track a difficult feature of an object.

This video is quite long. It's just over 13 minutes long to be precise. I would advise you watch it regardless, as it shows the process of manually tracking a challenging feature of the Object. If you can handle this one, you will definitely be able to handle any manual track. Please make sure you watch the next video as well, as they complement each other, and will overall, give you a good idea of the manual tracking process.

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Transcript

It's time to start tracking our object. In order to do that, I'm going to select two different features on my object. Mind you, we're using the scene that has already been solved for the camera. It hasn't been calibrated, but it doesn't make a difference. The process I'm going to show you applies to to any stage of your tracking, whether you've done the camera solve or not. It's only about tracking 2D features. I'm going to make a couple of videos. This one is going to show you how to track from end-to-end, a feature which is quite challenging. And, this is going to involve quite a lot of manual labor. The next video is going to show a feature that is much easier to track. Let's begin with a hard one. And let's go ahead and identify it. Let's scrub here, and see what we can find. Let's see, I'm going to find one that has some sort of overlapping. There you go. What I'm going to do, I'm going to Zoom into this one. This is nice and bright. But, it actually goes in front of this one over here. That's going to alter the pattern, so it's going to present some challenges which we will have to go and correct manually. Let's go to a nice part of our footage, somewhere around here. What I'm going to do is right-click, and Create use a track, center it, and make it flush. I think that's good enough. And, so that we can work easier, I'm going to open up a graph view. I'm going to drag this and dock it over here. What I want to do is go and Select AutoTracks. Then I'm going to Hide Selected. So now if I press H, I can only see my manual tracks and this is my first keyframe. Excellent. So I've created this. I'm going to rip out my motion tracker menu and put it here on the left. Keep auto-update tracks on for now. We may turn it off later on, and track bi-directionally and see what happens. It did its calculation. You can see it's moving around. Lock Fewer Tracks, to keep it fixed. Let's go and find...let's see what's going on here. And there is where we lose it. Now here's an odd thing, there's this tracker, and this may happen to you, just know that it's a limitation. Sometimes, it's very rare but it happens, an automatic tracker just appears out of nowhere. Just Select it, and just press Backspace, and Delete it. Apparently, this is not a random autotracker. It's a tracker that was deactivated by the Smart Acceleration Filter. By adding the manual tracker, we altered the Smart Acceleration's decision and it activated it again. Since originally it was not valid, though, by deleting it you're doing no harm. So that's why it's good to work with a clear view of what you're working on. That is just a minor limitation. Anyway, back to this. So if we move forward, you can see that the color changes, which means we have a higher error. Here you can see now, look at the top of the little sphere, it's actually starting to pop. That means that we're losing the center of our sphere. What I'm going to do is go around here, and right-click, and Insert key at track position. It's going to add a keyframe here and take a snapshot of this. So, now we know that at least this range is pretty much locked. Let's move a bit more. You can see we're getting this slipping here. It recovers somewhere here. It's pretty much centered. Let's right-click, Insert key at track position here. We have a bit of correction to do here if we choose to do so. I have to tell you that it's not that bad, so we can leave it as it is. But, here's where the problem starts. When the other feature enters the pattern area, that's where it starts moving around. What I'm going to do, well...first of all, it totally loses it after this point. I'm going to go and start setting keyframes at the first frame where I see some significant difference. And I'm going to use my keyboard shortcuts: G to go a frame forwards and F to go a frame backwards. I'm going to go between front and back quite a few times because this allows me to see the difference between the two frames. As you can see, from here to here, there's a slight motion of the feature. Down, you can see it goes down and up, down and up. The general rule of thumb is that when you're doing frame by frame manual tracking, you need to move your tracker in the same direction where the feature is moving. So you can see, the feature is going down. So press Command and Down-Arrow on your keyboard to make it go down. Then check it again. Now you can see that it's much steadier. Let's go to the next frame. It goes down. Press Command and Down-Arrow. Sometimes you may need to press your Down-Arrow a few times. You can see still, it seems to be going a bit downwards. That's good. It goes a bit to the right, doesn't it? So Command-Right, and back, front. Sometimes, by mistake, I go front instead of going back. Good. I'm just comparing the two. Then let's go to the next frame. This is down. I did two Command Down-Arrow clicks. I can't keep repeating Command Down-Arrow, Command Up-Arrow because then this video is going to end up being two hours. When the tracker is moving, you should assume that I'm actually pressing Command or Control on the PC and the arrow keys on my keyboard, which is the equivalent of nudging up and down and so forth. I have my fingers placed on F and G. And, depending on where the feature is going, I'm pressing the arrows. Every time I press the arrow, because the AutoUpdate Tracks is on, you will see just a fraction of a second where it does some sort of calculation. One thing you need to know is that if you are somewhere where a key doesn't exist, and it's just a calculated position of your tracker, if you can modify the position of the tracker, then a key will automatically be set over there, just like if you pressed Insert key at track position and then did the motion. So just remember that. Back, front, back, front, and I'm talking about the frame, back, front. That looks pretty good. Maybe a bit to the right. Back, front. Perfect. Front. It goes down, one, two, back, front, down, back, front, back, front, down, back, front, back, front, a bit to the right, back, front, back, front. Perfect. Front, down, back, front, back, front, front, back, front. Perfect. Maybe, a bit to the right. Oops, actually, that was wrong. There you go. Good. As you can see now, funny enough, it has tracked a few frames which are not that bad. But, here it starts moving again. There you go. That's where more movement appears. All you have to do is Insert a keyframe, and you can see that now, if you look here on the graph view, you can see that we have five frames that are calculated. So we saved ourselves five manual frames. Let's move on, let's see what goes on after this. Actually, that's not very bad. I think it's nearly perfect. That's fantastic. That's it. That's where the footage ends. Excellent. We've tracked this that way. You can see that there's generally a little bit of slippage, but we can get away with this amount of slippage. If you are such a perfectionist and you want this to be an absolutely perfect track, for the sake of it, then you may need to go and do a lot of manual key frames. Anyway, let's go into the other direction now. Backwards. And, see what happens here. We have pretty much the same situation. I go to the last frame, which is acceptable, Insert key in track position. You can see that quite a bit of calculation occurred. Here, we have a bit of a problem. I'm going to go here where it's good and Insert a key. Then I'm going to fiddle around with these intermediate ones. What I'm going to do is just work backwards, using my F key. So, backwards. There's a slight motion up. You can see here, it totally loses it. I'm pressing Command and Arrow key a few times. I don't have to. I can always go here and move it, but I don't like to remove my hand from my keyboard to my mouse. That is something that I find extremely irritating. So, you bring it close enough and then you just nudge it. Again, the golden rule is when you move to another frame and you see the feature moving in a certain direction, so now it's going a bit down and a bit to the left, that's where you need to push your tracker. Here we have a huge difference. So, I'm going to place this here, as accurately as possible. Front, back, and then move the tracker a bit down. Perfect. Next one. Here. Excellent. Go back, front. It goes to the left and goes down. Back, front, a bit to the left, back, front, a bit to the left, back, front. Perfect. Next one. Right, right, right, right, right, right, right. This is what's going to go on inside your head when you're actually doing this. So, down and to the left, to the left and down. There you go. Once you get the hang of this, it's interesting how you can just start moving on and working at very good speeds while you're listening to music or having conversation with friends. Because this is going to become very mechanical, you know, just muscle memory, as I'm doing it now and talking to you. Which, means I may do a mistake because my brain doesn't multi-, what's that word, see I forgot the word, multi-task, there you go. That's how bad I am at this thing. But once we're over this hurdle and we go this way... I'm quite excited because it seems... There you go. That's not bad. Right-click, Insert key at track position. Look here, it tracked a few more that way. Now one thing I need to focus your attention on is, sometimes when you do the insertion of the key and it does the bi-directional tracking, some of the frames that previously looked perfect they may change slightly. The fact that we've been through certain frames and we are happy with them doesn't mean that they won't change. Just be aware before you move to another feature of your track. Make sure that everything is in place. And, you can just do that by scrubbing through or playing your movie with your tracker locked in and you'll see any jumps and so forth. Let's go here. Right-click, Insert key at track position. It's going to do it calculations. Again, we have this movement. And then, it recovers. You can see it both in the numerical expression of the arrow, where it's a bit more orange, and visually. Right-click, Insert key. Now we've isolated this area in here, which we are going to correct. This looks good, good. There you go. Here, I'm going to Insert the key and move there. Now I'm going to move it down, manually first, and now use my Arrow keys. So, back, front, a bit to the left, back, front. Perfect. That goes down to the right. Back, front, back, front, down, back, front, back, front. Perfect. Very good. A bit up and a bit to the left. Maybe a bit down. You can change your mind, you're allowed to do that, it's your prerogative. Excellent. I think this goes a bit down, but I think it's so small it doesn't make a difference. You can see that the lock view was jumping a bit. This is something that happens rarely, but don't be alarmed, just go back and forth a few times and it will correct itself. Fantastic. Let's go here and let's move. We've only got a few frames to go. This looks good. Go here, Insert key at track position. Look at that. It created by that little imitation, I told you, an automatic track somewhere in your scene. The good thing about that that it's benign, it's benign. You just Select it and you Delete it. You can even Select it there. So, don't worry about it. If these ghost trackers appear, they're all good. There you go. Let's go back, let's Zoom in and let's play this. You will see that the feature is locked to the track. Unless we see some extraordinary jump or something that will pop out quite obviously, that means that the track is nearly perfect. There you go. This the process of a case of a difficult feature to track. You can be even more accurate if you're willing to go and keyframe manually most frames. To be honest with you, you can actually go and do every single frame manually to achieve the ultimate perfection, but believe me, you don't have to. If you want to though no one's stopping you from that.
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