In this video, we will track our main shots camera motion assisted by the focal length we calculated in the survey shot in the previous video. So let's double-click here. Copy this value by pressing Command C or Control C on the PC and let's open a new scene, and create a motion tracker object. Go to the footage tab and click here to load our footage. Blaster walk double click on any of the frames and the footage will be loaded. Let's go to a sample, make it a 100% so we have the full quality of our footage. Let's get it accustomed, change it to 16 by 9. And now let's correct the render output to 16 by 9 and everything is fantastic. Now before we start, I need to go to reconstruction. I need to tell the focal length that it's known and constant, and I'm going to paste. So Command V or Control V and all I have to do is go to motion tracker and full solve. You can see that it's pre-loading the footage in RAM. Now it's processing the frames which means it's actually conducting the 2D track. And now it's running the 3D solver on the 2D tracks. And with the help of some time traveling, the solve has finished. Let's see what it looks like in our 3D views. Press H. Click here, press H, click here, press H. Now you can see all these red trackers and these are the ones in the distance, and because here the resolution so to speak is much less, the detail is much less that's why they have a high error, and that's why they are red. You can see that the green ones are concentrated close to the camera. Now let's go to this view. Let's zoom in. And you would assume that I'm going to start rotating the motion tracker like I did before, but I'm not going to do that. What I am going to do, is use the proper way to calibrate my scene for orientation and scale. So I'm going to maximize this view, select the motion tracker and do the following. I'm going to go to the motion tracker menu, go to constraints and use a planer constraint. This is going to ask me for three points. And these three points need to lie on a plane that I know defines an axis. So the floor. I'm going to click here, then I'm going to click here, and then I'm going to click here. And in the attributes, I'm going to say that this defines the Y-axis. So go here and say Y. Let's go to our 3D view and now you can see that all these points are lying on the floor. Here in the planar constrained tags attributes, we can see the three nulls that define this plane. And they're all green which means that they're relatively good. But at any point, I can change them. I can either go and select one of these corners and pull it and take it to another point, or I can just go here and select another null. But I'm going to leave it as is for now. Something I failed to show in the original recording of this video is the following. When you select one of these constraint tags, you will see that we have this selection. I can use more than three nulls. So how do we do this? Well, you lock this palette, so it doesn't close. And then you go to your auto features...actually, you don't have to go. You just go and select some your auto features. So I'm going to deselect my tag. Go to my selection tool and select features here which I believe lie on the same plane. So I think these are enough. Then the next thing you need to do is go and find any one of them and drag them in the locked selection. So what this is going to do, it's going to take all the nulls you've placed in this box and average them out and find the plane. The next thing I'm going to do is find some two points which I can estimate very roughly the distance. And this will allow me to calibrate my scene for scale. Because at this point, the tracker doesn't know if these two points are one mile apart or one foot apart. So doing the same thing, motion tracker, constraints. I'm going to create a vector constraint, and I'm going to click on this one. And this one. Now I can always say that this is on the Z-axis. So it's going to orient my scene. So this is facing towards the Z. If I go here, I can navigate. And you can see this little blue line indicates Z-axis. Now let's think about this. What do you think is the distance between these things? I would say, judging from this here, It's about a foot and a half. I'm going to say 40 centimeters. So with the tag selected in the attributes, the length now is unknown. I'm going to say known. And I'm going to put 40 centimeters. And now my scene is calibrated for scale as well. There you go. And there you go. You can see there's a very slight incline. But that is probably because these points are not totally aligned. What I can do is, go here, use my move tool, click on this and drag it right over another one and you can see that the incline changes. It's actually worse, so I'm going to drag it and put it there. And I'm going to try to find a point that makes this look a bit more level. Maybe the problem is not that one. Maybe the problem is this one. So click and then click and drag. Ah, that looks better. Click and drag. No click and drag. Excellent. That looks much better, and I'm going to leave it as it is. One thing you need to be aware of is, if I try to navigate at this point using my navigation keys, I'm going to press one and click to navigate. You can see that the point moves. Undo. When a constraint tag is selected, then we cannot navigate. I have to deselect it and then navigate using my keys. So what I was trying to say was that currently, the camera is at the zero, zero, zero point. I don't want the camera to be at the zero, zero, zero point. I want the floor to be leveled with the zero. So what I'm going to do, is add a third type of constraint motion tracker constraint and I'm going to use a position constraint. I'm going to click on this point. And you can see it defaults to zero, zero, zero for XYZ. And now my scene... I'm going to deselect this so I can navigate, is calibrated perfectly. Let's go and test it with some geometry. I'm going to make cube which is 50 centimeters. On each axis, I'm going to raise it 25 centimeters. And I'm going to use my move tool to move it somewhere over here. And now I'm going to deselect everything, rewind, press play, and you can see that the cube is nicely stuck to the ground. We have successfully tracked and calibrated our scene. The next step is to go and track the object, the prop that this good lady is holding.