WEBVTT 00:00:00.512 --> 00:00:02.560 This chapter is for everyone 00:00:03.584 --> 00:00:06.656 who has either watched my previous DVD about Tracking in Blender, 00:00:07.168 --> 00:00:10.240 or who are familiar with other tracking application. 00:00:10.752 --> 00:00:14.848 So I won't go into detail about why the focal length is important? 00:00:15.104 --> 00:00:17.664 What Camera Tracking is? 00:00:18.944 --> 00:00:19.968 And what Camera Tracking is all about? 00:00:20.480 --> 00:00:24.064 Just going to focus on the workflow and the interface, 00:00:24.320 --> 00:00:26.880 and the changes to the previous version in Blender. 00:00:27.648 --> 00:00:28.928 To get started, 00:00:29.184 --> 00:00:32.000 let's go to the Motion Tracking layout, 00:00:32.256 --> 00:00:34.304 where you find the Main Window 00:00:34.560 --> 00:00:36.352 and the Open button. 00:00:37.120 --> 00:00:38.912 Let's open up the footage. 00:00:39.168 --> 00:00:42.752 In the Camera Tracking folder, I go to Footage, 00:00:43.008 --> 00:00:43.776 then open 00:00:44.032 --> 00:00:45.056 "Factory 3", 00:00:45.568 --> 00:00:46.592 open the clip, 00:00:47.104 --> 00:00:47.872 press F 00:00:48.128 --> 00:00:49.152 for "fit to view", 00:00:49.408 --> 00:00:52.736 and then Shft spacebar to make this window full screen. 00:00:53.248 --> 00:00:56.832 F again, to make it fit to the view, and now we can start tracking. 00:00:57.344 --> 00:01:00.416 If you didn't use Blender track for a while, 00:01:00.672 --> 00:01:01.696 then let me give you a brief overview 00:01:01.952 --> 00:01:04.256 over what's changed in the Interface. 00:01:05.024 --> 00:01:09.120 On the left-hand in the Tool shelf, we have now tabs. 00:01:09.888 --> 00:01:14.240 There's a tab for Tracking, where you will find all the operators 00:01:14.496 --> 00:01:16.800 for setting up your Clip, adding Markers, 00:01:17.056 --> 00:01:19.872 doing the Tracking Settings, and of course, 00:01:20.128 --> 00:01:21.152 performing the actual tracking. 00:01:21.920 --> 00:01:26.272 And then, there is the "Solve" tab, where you will find all the solving options. 00:01:27.552 --> 00:01:29.344 We will use all these later. 00:01:29.600 --> 00:01:32.160 First, let's go back to the Tracking tab. 00:01:32.416 --> 00:01:35.488 On the right side, there are all the properties 00:01:35.744 --> 00:01:37.024 of the current track, 00:01:37.280 --> 00:01:40.096 of the footage, of the entire clip, 00:01:40.352 --> 00:01:42.144 and some other things. 00:01:42.912 --> 00:01:43.936 Now, to get started, 00:01:44.192 --> 00:01:46.496 let's first load this into the memory, 00:01:47.008 --> 00:01:49.312 by going to Clip, and then Prefetch, 00:01:49.824 --> 00:01:52.128 you will find this purple line here. 00:01:52.640 --> 00:01:54.688 The Cache Bar will fill up this 00:01:56.480 --> 00:01:57.248 with this colour. 00:01:57.760 --> 00:02:00.576 So, we know, this is now in our memory. 00:02:01.600 --> 00:02:03.392 Let's add a first marker. 00:02:03.904 --> 00:02:06.208 Add menu, and then click here. 00:02:06.720 --> 00:02:08.256 Or even simpler, 00:02:08.512 --> 00:02:09.792 Ctrl left click 00:02:10.048 --> 00:02:12.864 on any trackable feature, 00:02:13.120 --> 00:02:15.680 for example, this contrasted point 00:02:16.192 --> 00:02:17.728 at the bottom of the column. 00:02:18.496 --> 00:02:21.824 And if you want to move it later, just press G to grab it, 00:02:22.080 --> 00:02:23.104 then you can 00:02:23.360 --> 00:02:24.128 move it around. 00:02:24.640 --> 00:02:28.224 Or you can also move it around in the Track Preview up here, 00:02:28.480 --> 00:02:31.296 by left clicking and dragging this feature point. 00:02:32.576 --> 00:02:35.904 What you see here is Blender's pattern area. 00:02:36.672 --> 00:02:37.696 Can scale it up 00:02:37.952 --> 00:02:40.512 by using this little handle here, 00:02:41.024 --> 00:02:42.816 or just by pressing S. 00:02:44.352 --> 00:02:49.216 If you want to see the search area, which of course we also have, you can press Alt S, 00:02:49.728 --> 00:02:53.824 or look for the search area here in the Marker Display panel. 00:02:56.384 --> 00:02:58.432 Tracking Blender is very easy. 00:02:58.688 --> 00:03:00.480 Just press the Track Forward button, 00:03:02.272 --> 00:03:03.040 that would track quite fast. 00:03:03.552 --> 00:03:07.392 And if you want to be able to focus on the track while it's tracking, 00:03:07.648 --> 00:03:10.720 you can center the view to the marker by pressing L, 00:03:11.232 --> 00:03:12.256 and that will lock 00:03:12.512 --> 00:03:13.280 the view 00:03:13.536 --> 00:03:14.560 to this marker. 00:03:15.072 --> 00:03:17.120 Now it will be centered all the time. 00:03:19.424 --> 00:03:21.984 Shft left arrow to go back to the first frame, 00:03:22.496 --> 00:03:23.520 then F 00:03:23.776 --> 00:03:25.056 for "fit to view" again, 00:03:25.312 --> 00:03:28.896 and then with the middle mouse button, you can also move your footage. 00:03:30.944 --> 00:03:32.992 So that's Tracking in Blender. 00:03:33.248 --> 00:03:35.552 Just grab a marker, press Track Forward. 00:03:36.064 --> 00:03:39.392 If there's Track Forward, of course, there's also Track Backwards. 00:03:39.648 --> 00:03:42.976 So Ctrl left click again on another marker. 00:03:43.232 --> 00:03:46.560 Maybe, use this point at the bottom of the column again, 00:03:46.816 --> 00:03:47.840 and track backwards. 00:03:48.864 --> 00:03:49.632 Very easy. 00:03:50.912 --> 00:03:52.960 In the previous versions of Blender, 00:03:53.472 --> 00:03:56.032 though it's already quite a while ago, 00:03:56.288 --> 00:03:57.824 so this was on the previous Tracking DVD, 00:04:00.640 --> 00:04:03.712 you have SAD Tracking, KLD Tracking, and Hybrid Tracking, 00:04:05.248 --> 00:04:06.528 in the Tracking settings. 00:04:07.296 --> 00:04:10.880 We don't have them anymore. Now, we have different Motion Models. 00:04:11.904 --> 00:04:14.720 So the Tracking in Blender is always quite precise. 00:04:15.232 --> 00:04:16.768 Find the Tracking settings, 00:04:17.024 --> 00:04:18.303 there is the Motion, 00:04:18.559 --> 00:04:19.583 set to Location, 00:04:19.839 --> 00:04:21.375 and we have Prepass enabled. 00:04:21.887 --> 00:04:24.447 Prepass is the equivalent 00:04:24.703 --> 00:04:25.983 of the old Hybrid Tracking, 00:04:26.495 --> 00:04:28.543 which will perform a brute force search 00:04:28.799 --> 00:04:31.103 in the search area for the feature. 00:04:31.359 --> 00:04:32.639 If disable that, 00:04:32.895 --> 00:04:37.759 Tracking will be even faster. But Blender will also eventually lose the track more easily. 00:04:39.039 --> 00:04:41.855 But sometimes, it can work even without Prepass. 00:04:42.623 --> 00:04:44.927 In this case, you can find here where it just leave the frame, 00:04:45.183 --> 00:04:46.719 it is disabled. 00:04:47.999 --> 00:04:50.559 Usually I keep Prepass enabled 00:04:51.071 --> 00:04:51.839 because 00:04:52.351 --> 00:04:54.655 it's still fast enough and would be more accurate. 00:04:55.423 --> 00:04:56.959 Now, what's up with the Motion Model? 00:04:57.471 --> 00:05:03.615 That's interesting, because we can make Blender deform the marker, for example, 00:05:03.871 --> 00:05:04.639 for Rotation, 00:05:04.895 --> 00:05:07.967 Location n Scale, or Location Rotation Scale. 00:05:08.991 --> 00:05:11.295 Even more interesting, Affine or Perspective. 00:05:12.319 --> 00:05:15.391 So let's say, I add the marker here on the floor, 00:05:15.903 --> 00:05:18.463 then I would scale it up a little bit more. 00:05:19.231 --> 00:05:21.535 And if I track that now, you can see, 00:05:21.791 --> 00:05:23.583 it deforms with the footage. 00:05:23.839 --> 00:05:26.399 So that's very very accurate and very nice. 00:05:26.655 --> 00:05:28.191 If you look at the preview 00:05:28.447 --> 00:05:29.215 up there, 00:05:29.983 --> 00:05:33.567 it's barely changing at all. 00:05:33.823 --> 00:05:34.847 So this is a rock solid marker. 00:05:35.103 --> 00:05:35.615 Awesome. 00:05:36.383 --> 00:05:42.527 So this is always useful if you track something on the floor, and the camera is moving, 00:05:42.783 --> 00:05:43.551 perspective is changing, 00:05:43.807 --> 00:05:46.111 then this will make it easier for Blender 00:05:46.367 --> 00:05:48.159 to really track the feature 00:05:48.415 --> 00:05:50.463 more accurately. 00:05:50.719 --> 00:05:51.231 And also, 00:05:51.743 --> 00:05:54.047 can help you to have longer tracks. 00:05:56.607 --> 00:05:58.911 So that's the Motion Model. 00:05:59.935 --> 00:06:04.031 What didn't change is the Keyframe or Previous Frame setting. 00:06:04.543 --> 00:06:08.127 So usually it will look for a keyframe, which means, 00:06:08.639 --> 00:06:09.919 if you have a marker, 00:06:14.015 --> 00:06:17.087 let's use something here, 00:06:17.343 --> 00:06:17.855 if I track 00:06:18.111 --> 00:06:20.927 frame by frame with Alt right arrow, 00:06:21.695 --> 00:06:23.743 up to frame 72, 00:06:23.999 --> 00:06:29.375 and change something on the marker, for example, changing the search size, 00:06:29.631 --> 00:06:32.191 then this would add a keyframe to this track 00:06:32.447 --> 00:06:34.495 or to the marker. 00:06:34.751 --> 00:06:37.055 And you can see that, if I track forward now, 00:06:37.311 --> 00:06:41.407 this yellow bar, which indicate the already tracked frames, 00:06:41.663 --> 00:06:42.943 will have this little darker yelllow spot. 00:06:43.967 --> 00:06:46.783 So that's the keyframe, 00:06:47.295 --> 00:06:50.879 and this will be the reference point for every new frame that I'm tracking. 00:06:51.903 --> 00:06:56.767 In some situations, it can help to change that from Keyframe to Previous Frame. 00:06:57.791 --> 00:07:03.935 And if I want to do that for the current marker now, I cannot do that over here. 00:07:04.191 --> 00:07:04.703 For that, you go to the Tracking settings. 00:07:05.471 --> 00:07:09.055 Those will always be the settings for the current active marker. 00:07:09.823 --> 00:07:13.919 So I go here and change from Matching to Previous Frame, 00:07:14.175 --> 00:07:15.967 and I can still track forward. 00:07:16.735 --> 00:07:18.527 The benefit is, 00:07:18.783 --> 00:07:20.575 sometimes it helps you to track longer, 00:07:20.831 --> 00:07:23.391 but will also increase the probability of sliding markers, 00:07:25.951 --> 00:07:26.975 which is not really nice. 00:07:28.255 --> 00:07:30.815 So that's the Manual Tracking in Blender. 00:07:31.327 --> 00:07:32.863 And 00:07:33.119 --> 00:07:36.703 since these tracks are now finished, let's lock them with Ctrl L. 00:07:37.471 --> 00:07:41.055 If you come from other tracking applications, then you know that 00:07:41.567 --> 00:07:46.175 there's this Point Cloud Tracking, where you have lots and lots of feature points that are being tracked. 00:07:46.687 --> 00:07:49.759 Blender is designed for supervised tracking. 00:07:50.015 --> 00:07:53.087 So what we have been doing here is actually the way to go. 00:07:53.855 --> 00:07:56.927 Still, if you want to have something a little bit more automatic, 00:07:57.183 --> 00:07:58.975 you can use Feature Detection. 00:07:59.743 --> 00:08:03.071 So here, in the Marker panel, we have Detect Features, 00:08:04.607 --> 00:08:07.167 and that will track the frame for trackable spot, 00:08:08.447 --> 00:08:10.751 and then you can start tracking. 00:08:11.775 --> 00:08:16.639 Now the thing is, if you track them forward now, Blender will not add new markers, 00:08:16.895 --> 00:08:19.711 if some of those markers has been disabled. 00:08:20.735 --> 00:08:25.599 Also, it will use the setting that you had here in the Tracking settings. 00:08:25.855 --> 00:08:27.903 Currently, I'm using Affine Tracking, 00:08:28.415 --> 00:08:31.487 which is much more CPU intensive than location based tracking, 00:08:32.511 --> 00:08:34.559 which is why this is now very slow. 00:08:34.815 --> 00:08:36.607 Maybe I should have changed that before. 00:08:37.375 --> 00:08:39.167 Anyway let's track this to the end. 00:08:40.447 --> 00:08:43.519 You can already see that there are some of those red squares. 00:08:45.055 --> 00:08:47.103 Those are the disabled markers. 00:08:48.127 --> 00:08:51.711 So a marker that stops tracking will be automatically disabled. 00:08:53.247 --> 00:08:57.855 So Feature Detection is not the same thing as the point cloud tracking 00:08:58.111 --> 00:08:59.391 you have in other applications, 00:09:00.159 --> 00:09:05.023 for example, in the after effects camera tracker or the new cinema 4D tracker, 00:09:05.279 --> 00:09:06.303 it's just different. 00:09:06.815 --> 00:09:10.911 Now the thing is, if you use Detect Features, then it's much more likely 00:09:11.167 --> 00:09:14.751 that some of those tracks will start doing crazy things. 00:09:16.287 --> 00:09:19.103 So you can go and scrap to the shot 00:09:19.359 --> 00:09:22.175 and check for weird markers with weird behaviour. 00:09:22.431 --> 00:09:26.015 But there's a tool that makes it easier to see those faulty tracks, 00:09:26.271 --> 00:09:27.807 and that's the Curve View. 00:09:28.319 --> 00:09:31.647 So if we leave the full screen mode with Shft Spacebar, 00:09:32.159 --> 00:09:35.231 then you have the Curve View up here. 00:09:36.255 --> 00:09:37.023 And usually, 00:09:37.279 --> 00:09:38.815 this should automatically be set 00:09:39.071 --> 00:09:41.887 to your current footage, to the active clip, which is here, 00:09:43.167 --> 00:09:43.935 "Factory 3". 00:09:44.959 --> 00:09:47.263 So let's change this to that clip, 00:09:47.519 --> 00:09:49.055 and here you will have now, 00:09:49.567 --> 00:09:51.359 the speed values 00:09:51.615 --> 00:09:53.663 for X and Y for each marker. 00:09:55.711 --> 00:09:58.271 And you can see that some of those tracks 00:09:58.527 --> 00:09:59.807 have thess spikes, 00:10:00.575 --> 00:10:02.623 which tells you that they have a problem. 00:10:03.391 --> 00:10:09.279 Now, you can select those curves, and just go ahead and delete them by pressing X 00:10:09.535 --> 00:10:11.327 or delete on your keyboard. 00:10:12.351 --> 00:10:13.375 And 00:10:13.631 --> 00:10:15.679 after you delete all these curves, 00:10:15.935 --> 00:10:17.983 you should be good to go, in theory. 00:10:18.495 --> 00:10:22.335 If you have tracked enough markers, then you can go ahead and solve that. 00:10:22.847 --> 00:10:24.127 Now, how many are enough? 00:10:24.383 --> 00:10:25.663 Well, you need at least 00:10:26.175 --> 00:10:28.735 8 common tracks on both keyframes. 00:10:29.247 --> 00:10:30.271 Now what's a keyframe? 00:10:31.039 --> 00:10:34.111 Maybe, let's just first go over to this Solve panel. 00:10:35.647 --> 00:10:37.183 Also go full screen again, 00:10:37.695 --> 00:10:38.207 Solve panel, 00:10:38.463 --> 00:10:41.535 and then here, you will find Keyframe A and B. 00:10:42.047 --> 00:10:48.191 These keyframes are the initial frames that Blender use to establish the perspective 00:10:48.447 --> 00:10:49.983 and the reconstruction of the scene. 00:10:50.751 --> 00:10:54.335 And once it has that, would iterate over the other frames, 00:10:54.591 --> 00:10:55.615 and solve them too. 00:10:56.383 --> 00:10:57.663 So you can set them by hand. 00:10:57.919 --> 00:11:00.991 Keyframe A and B, and it makes sense to set them 00:11:01.503 --> 00:11:03.551 so there's lots perspective going on. 00:11:03.807 --> 00:11:07.391 For example, this would be a good candidate for Keyframe B. 00:11:08.415 --> 00:11:10.975 You can also make Blender to calculate that. 00:11:11.231 --> 00:11:12.511 That's also something new. 00:11:12.767 --> 00:11:14.303 So if you check Keyframe, 00:11:15.583 --> 00:11:17.887 and then click on Solve Camera Motion, 00:11:18.143 --> 00:11:20.447 Blender will first go over the tracks, 00:11:21.215 --> 00:11:23.007 try to select the best keyframes. 00:11:24.287 --> 00:11:26.079 The problem is, this can take quite long. 00:11:26.335 --> 00:11:28.383 And if there are problematic tracks, 00:11:28.639 --> 00:11:30.431 it can lead to weird results. 00:11:30.687 --> 00:11:31.711 For example, here, 00:11:31.967 --> 00:11:34.527 Keyframe A is 1, Keyframe B is 10, 00:11:36.575 --> 00:11:37.343 and that's weird results, 00:11:37.855 --> 00:11:39.903 that doesn't really look good. 00:11:42.975 --> 00:11:43.743 For me, personally, 00:11:43.999 --> 00:11:46.815 I think it's more safe to do it not automatic, but by yourself. 00:11:47.071 --> 00:11:50.911 So let's set Keyframe View to 150, 00:11:51.423 --> 00:11:53.727 where I can be sure that there is enough perspective. 00:11:54.495 --> 00:11:56.031 If you Solve this again, 00:11:56.543 --> 00:11:58.335 can see, it's even faster, 00:11:58.591 --> 00:12:00.639 and the Solve error is better. 00:12:01.663 --> 00:12:06.015 That is still not great. So we can perform a clean up of the markers. 00:12:06.527 --> 00:12:09.599 So we go to Cleanup, and say 00:12:10.111 --> 00:12:13.951 let's erase tracks that are shorter than 20. 00:12:14.463 --> 00:12:15.743 And also select markers 00:12:15.999 --> 00:12:18.047 where the Solve Error is higher than 1. 00:12:19.583 --> 00:12:22.911 If you press Clean Tracks now, it'll select all of those. 00:12:23.935 --> 00:12:26.751 Maybe this is a little bit too much, 00:12:27.007 --> 00:12:28.287 so let's set Solve Error to 2. 00:12:29.567 --> 00:12:32.895 Deselect them, Clean Tracks again and just erase those. 00:12:33.407 --> 00:12:34.175 Solve again, 00:12:34.687 --> 00:12:36.991 and the solve error is a little bit better now. 00:12:37.503 --> 00:12:40.319 Of course, what's missing is the correct camera data. 00:12:41.855 --> 00:12:46.975 So just as another application, you have to tell Blender what camera you have been using. 00:12:47.231 --> 00:12:51.327 So we go to the Properties on the right side, go to Camera, 00:12:51.839 --> 00:12:54.143 either set the sensor size yourself, 00:12:54.399 --> 00:12:55.679 or you can also choose 00:12:56.191 --> 00:12:57.983 from a bunch of presets. 00:12:58.751 --> 00:13:01.055 Now with Presets, for lots of cameras, 00:13:01.823 --> 00:13:05.151 the Arri Alexa, Blackmagic, or the camera 00:13:05.407 --> 00:13:06.431 I've been using, 00:13:06.687 --> 00:13:09.247 a Canon APS-C camera. 00:13:09.759 --> 00:13:11.807 This was the Canon 550D, 00:13:12.319 --> 00:13:13.855 it belongs to the family of 00:13:14.111 --> 00:13:15.135 Canon APS-C cameras. 00:13:17.439 --> 00:13:19.231 So sensor width has changed to 22.3, 00:13:19.487 --> 00:13:22.559 and of course, we need to set the correct focus length. 00:13:23.071 --> 00:13:26.399 Now the focal length will probably be something around 20. 00:13:27.423 --> 00:13:28.959 I don't know for sure. 00:13:30.495 --> 00:13:31.775 So let's try these settings. 00:13:32.031 --> 00:13:34.591 Once we set them, we can solve again. 00:13:35.615 --> 00:13:38.175 0.7, which is quite good already. 00:13:38.431 --> 00:13:39.967 But we don't need to stop here. 00:13:40.223 --> 00:13:42.783 We can also make Blender 00:13:43.551 --> 00:13:45.599 estimate the better focal length. 00:13:46.367 --> 00:13:46.879 So, 00:13:47.135 --> 00:13:48.159 go to Refine, 00:13:48.415 --> 00:13:49.695 set it to Focal Length, 00:13:49.951 --> 00:13:51.231 Solve the camera motion, 00:13:51.743 --> 00:13:54.815 and you can see the focal length is actually probably 00:13:55.071 --> 00:13:57.375 more something like 20.6. 00:13:58.911 --> 00:14:03.263 Since this was a cheap len, there is for sure some lens distortion, 00:14:03.519 --> 00:14:04.287 and can make 00:14:04.543 --> 00:14:06.079 Blender calculate that as well. 00:14:07.615 --> 00:14:10.943 So go to Refine, set to K1 and K2, 00:14:11.711 --> 00:14:12.479 Solve again, 00:14:12.991 --> 00:14:15.295 you will find these values now change, 00:14:15.807 --> 00:14:18.111 the Solve Error goes down a lot. 00:14:18.367 --> 00:14:20.671 So this is actually a very good solution now, 00:14:20.927 --> 00:14:22.207 0.2, 00:14:22.719 --> 00:14:24.767 and can even check how this would look like, 00:14:25.023 --> 00:14:26.303 if it would be Understorted. 00:14:27.583 --> 00:14:29.375 So, that's a little bit better. 00:14:30.143 --> 00:14:30.655 Probably, 00:14:30.911 --> 00:14:34.239 it would make sense to track some of the features 00:14:34.495 --> 00:14:36.799 that're on the outside or the borders of the frame. 00:14:37.055 --> 00:14:39.103 Just to give Blender a little bit more information 00:14:40.895 --> 00:14:41.919 about how the footage looks like, 00:14:42.175 --> 00:14:43.711 at the borders of the frame, 00:14:43.967 --> 00:14:46.783 where you will typically find the most lens distortion. 00:14:48.063 --> 00:14:49.599 So we can try to track 00:14:49.855 --> 00:14:51.391 a few more markers here, 00:14:51.647 --> 00:14:52.927 in these areas. 00:14:53.951 --> 00:14:54.463 And then, 00:14:54.719 --> 00:14:55.743 Solve that again, 00:14:56.255 --> 00:14:57.791 and hopefully, Blender will then 00:14:59.327 --> 00:15:00.607 get a better estimate of the lens distortion. 00:15:01.887 --> 00:15:06.495 Now one thing I didn't mention yet is that, you can clear a path of a marker. 00:15:06.751 --> 00:15:07.775 So here, 00:15:08.031 --> 00:15:11.615 I suspect that this marker is sliding a little bit 00:15:11.871 --> 00:15:13.151 on the border of the frame, 00:15:13.663 --> 00:15:14.687 so we can go ahead 00:15:15.199 --> 00:15:17.247 and with the marker selected, 00:15:17.503 --> 00:15:19.039 go back to the Tracking tab, 00:15:19.295 --> 00:15:20.831 the Tracking panel, 00:15:21.343 --> 00:15:23.135 and then clear the path forward. 00:15:24.415 --> 00:15:25.695 That'll get rid of 00:15:25.951 --> 00:15:28.767 all the sliding frames of this marker. 00:15:29.535 --> 00:15:30.559 Solve again, 00:15:35.423 --> 00:15:37.471 this should make it a little bit better now. 00:15:38.495 --> 00:15:43.615 Now, there's another nice tool that has been added to Blender, which I didn't cover yet on the previous DVD, 00:15:43.871 --> 00:15:46.431 and that is the Refine Forward and Backward button. 00:15:47.199 --> 00:15:51.039 That's very handy if you have a marker that leaves the frame, 00:15:51.295 --> 00:15:53.087 or something goes in front of it, 00:15:54.367 --> 00:15:55.647 which I don't have in this example, 00:15:55.903 --> 00:15:58.719 but let's just generate an example. 00:15:59.487 --> 00:15:59.999 So 00:16:00.255 --> 00:16:01.791 I put the marker 00:16:02.047 --> 00:16:02.559 here, 00:16:03.071 --> 00:16:08.191 track a few frames forward. And now, for some reason, I have to disable the marker. 00:16:08.703 --> 00:16:10.495 Maybe something goes 00:16:11.007 --> 00:16:12.287 in front of the feature here, 00:16:12.543 --> 00:16:13.055 or at least, frame. 00:16:14.079 --> 00:16:15.615 I just tracked up to this frame 00:16:16.127 --> 00:16:18.943 and go a few frames forward. 00:16:19.711 --> 00:16:20.479 Now let's say, 00:16:21.247 --> 00:16:24.831 I want to continue tracking this feature. 00:16:25.855 --> 00:16:30.463 I pressed G to enable the Marker again, and move it to the position where I think 00:16:30.719 --> 00:16:31.743 I had it tracking. 00:16:32.767 --> 00:16:35.327 I don't know for sure because I don't really have a reference. 00:16:36.095 --> 00:16:39.935 And if I continue tracking now, I can happily do that, 00:16:40.703 --> 00:16:41.215 but, 00:16:41.983 --> 00:16:43.775 it might be a different spot, 00:16:44.799 --> 00:16:47.871 as I have left the marker on frame 66. 00:16:49.407 --> 00:16:54.271 Another nice thing is that, I can use this Refine Forward button 00:16:54.527 --> 00:16:57.855 on the first frame, where I have enabled the Marker again, 00:16:58.111 --> 00:17:00.671 and Blender will automatically compare that 00:17:01.183 --> 00:17:04.255 to the last reference frame here. 00:17:04.767 --> 00:17:06.815 Now I can continue tracking from here. 00:17:07.327 --> 00:17:10.399 So now, I can be sure that, even if I disable a marker, 00:17:10.911 --> 00:17:12.191 and enable it again, 00:17:12.447 --> 00:17:14.751 even if it's a totally wrong spot, 00:17:15.263 --> 00:17:16.543 Blender will be able 00:17:17.567 --> 00:17:22.175 to come up with a better placement for the marker, so that I'm always tracking the correct spot. 00:17:23.711 --> 00:17:24.991 Let me just delete this track, 00:17:26.015 --> 00:17:27.295 and now proceed. 00:17:28.063 --> 00:17:30.111 So what now? We have a solution, 00:17:31.135 --> 00:17:33.695 and we want to see that in the Camera View. 00:17:34.207 --> 00:17:38.047 So we have to do is, change this to the 3D Viewport, 00:17:40.607 --> 00:17:44.191 maybe split the view, so that we can open up the Properties, 00:17:44.959 --> 00:17:46.751 and then grab the camera, 00:17:47.519 --> 00:17:48.799 then setup 00:17:49.311 --> 00:17:49.823 Constraint, 00:17:51.103 --> 00:17:52.127 Camera Solver, 00:17:52.895 --> 00:17:55.967 and this will put in all the tracks for you. 00:17:56.223 --> 00:17:59.295 This will place the camera on the correct Motion path, 00:17:59.807 --> 00:18:01.343 this will now work. 00:18:02.111 --> 00:18:03.647 This is a little bit tedious. 00:18:04.415 --> 00:18:09.023 So the easier thing to do would be, instead of doing it manually, 00:18:09.535 --> 00:18:11.583 to go to the Solve tab, 00:18:12.095 --> 00:18:14.655 scroll down, and then Setup a Tracking Scene. 00:18:15.167 --> 00:18:19.263 This will set up a camera solver for you. It would put the footage 00:18:20.543 --> 00:18:21.567 in the background of your camera. 00:18:21.823 --> 00:18:24.639 So if you press 0 to look through the camera, 00:18:24.895 --> 00:18:25.919 you'll see your footage. 00:18:26.431 --> 00:18:29.247 And the only thing that's missing now is the proper alignment. 00:18:30.271 --> 00:18:34.111 To do that, you just grab 3 markers on the floor, 00:18:35.647 --> 00:18:37.439 and go to the Orientation panel, 00:18:37.695 --> 00:18:38.975 set Floor, 00:18:39.487 --> 00:18:42.559 which already place your camera in the correct position. 00:18:42.815 --> 00:18:46.655 Then what you can do next is to grab one marker, 00:18:46.911 --> 00:18:48.191 Set it as the Origin, 00:18:48.447 --> 00:18:51.007 and another one, Set it onto the X-axis, 00:18:51.263 --> 00:18:52.799 this will rotate your camera correctly. 00:18:54.847 --> 00:18:58.687 One thing I didn't mention yet, that is, 00:18:58.943 --> 00:19:00.223 now we finally have a proper tripod solver, 00:19:00.735 --> 00:19:03.295 so if you have a shot like this, 00:19:03.807 --> 00:19:04.831 where you only have rotating camera 00:19:05.343 --> 00:19:07.903 that didn't move at all, 00:19:08.159 --> 00:19:09.183 a typical tripod shot. 00:19:09.951 --> 00:19:11.487 What you can do is, 00:19:11.743 --> 00:19:14.303 track features as you would always do, 00:19:14.815 --> 00:19:16.607 you don't even have to track that many. 00:19:17.375 --> 00:19:17.887 I mean, 00:19:18.143 --> 00:19:19.679 you wouldn't even get away with 3, 00:19:20.959 --> 00:19:22.751 although that would give you a good solution. 00:19:23.263 --> 00:19:25.823 The point is, just track those markers, 00:19:26.335 --> 00:19:27.359 and before you solve, 00:19:28.383 --> 00:19:30.175 you just activate the Tripod button. 00:19:31.199 --> 00:19:33.759 You don't even have to add keyframe. 00:19:34.527 --> 00:19:36.831 You can even activate Refinement, 00:19:37.599 --> 00:19:40.415 and then Solve the Camera Motion. 00:19:40.671 --> 00:19:43.231 And that will Solve this as a tripod shot. 00:19:43.743 --> 00:19:47.327 The camera will only be rotating and will not move at all, 00:19:47.839 --> 00:19:50.399 and Blender will even calculate the proper focal length 00:19:50.655 --> 00:19:54.495 and lens distortion, which is really nice. 00:19:55.519 --> 00:19:58.079 So if you go and set up the tracking scene now, 00:19:59.359 --> 00:20:01.919 you can see that Blender has now 00:20:02.687 --> 00:20:03.711 this spherical shape, 00:20:03.967 --> 00:20:05.247 and the camera itself 00:20:05.503 --> 00:20:06.527 is only rotating, 00:20:06.783 --> 00:20:09.855 so we can do with it whatever we want. 00:20:10.111 --> 00:20:11.903 So if we rotate the camera, 00:20:13.183 --> 00:20:15.999 the 3D points will always stick to the view. 00:20:16.255 --> 00:20:17.279 And you can 00:20:18.815 --> 00:20:20.351 nicely align your scene manually. 00:20:20.863 --> 00:20:23.423 So, that's Tripod Solving in Blender. 00:20:24.447 --> 00:20:27.263 Of course they are still new tools we didn't cover yet. 00:20:27.519 --> 00:20:32.639 For example, different distortion model if you want to use GoPro for tracking, 00:20:33.151 --> 00:20:36.735 or the Plane Track which is very interesting for compositing, 00:20:36.991 --> 00:20:38.015 and of course, 00:20:38.271 --> 00:20:40.831 the very powerful Masking mode in Blender. 00:20:42.111 --> 00:20:44.671 But those will be for later chapters in this course. 00:20:45.183 --> 00:20:49.023 I hope that this would get you up and running with Tracking in Blender.