WEBVTT 1 00:00:00.001 --> 00:00:07.000 Tracking constraints are a type of constraint that allows for one object to point to another object in some way. 2 00:00:07.000 --> 00:00:20.000 Instead of copying the values of another object, tracking constraints take into account the relative location of the reference object, or target object, in relation to the selected object. 3 00:00:20.000 --> 00:00:24.000 Let's go ahead and look at how each of these tracking constraints work. 4 00:00:24.000 --> 00:00:31.000 Keep in mind that all of the constraints and concepts we show in this video are the same for bone constraints as well. 5 00:00:31.000 --> 00:00:37.000 So let's start with the most basic tracking constraint, the track 2 constraint. 6 00:00:37.000 --> 00:00:47.000 First things first, because the track 2 constraint does affect rotation of the object, let's use a monkey instead of a cube to make it more obvious. 7 00:00:47.000 --> 00:00:53.000 You can do this by deleting the cube and going to the Add menu, going to Mesh, and selecting Monkey. 8 00:00:54.000 --> 00:01:00.000 From here, we can select our monkey and go to the Constraints tab in the Properties Editor to add our constraint. 9 00:01:00.000 --> 00:01:04.000 Under the dropdown, you can choose Track 2. 10 00:01:04.000 --> 00:01:11.000 We can already see that we need to input a target object. This will be our light, because it's already in the scene. 11 00:01:11.000 --> 00:01:18.000 We can either select it from the dropdown menu, or use the eyedropper tool to left-click it in our 3D viewport. 12 00:01:19.000 --> 00:01:26.000 Immediately, the monkey starts to face the light. Except that it's not actually facing the light, it's facing directly away from the light. 13 00:01:26.000 --> 00:01:34.000 But still, if we move our monkey or our light, it's clear its transformation is taking the light's location into consideration. 14 00:01:34.000 --> 00:01:38.000 So how do we get our monkey to stare at the light object? 15 00:01:38.000 --> 00:01:44.000 Well, let's go into the track 2 constraint options, and you'll see a few axes we can choose from. 16 00:01:45.000 --> 00:01:52.000 What does this mean? Well, these axes correlate to our monkey's local axes, but it's not very easy to visualize. 17 00:01:52.000 --> 00:02:00.000 So let's go into our object settings under this orange cube icon in the Properties Editor, and go down to Viewport Display. 18 00:02:00.000 --> 00:02:04.000 Expanding this will reveal a couple of checkboxes, including axis. 19 00:02:04.000 --> 00:02:10.000 Check this on, and you'll see that we can now see the axes of our object visually in our viewport. 20 00:02:11.000 --> 00:02:17.000 Now, if we go back to our Constraints tab, these axes' letters might make a bit more sense. 21 00:02:17.000 --> 00:02:23.000 For example, up being the z-axis, and y being the 2-axis. 22 00:02:23.000 --> 00:02:31.000 So it's clear that the y-axis is pointing at the light object, and the z-axis is considered up for the object. 23 00:02:31.000 --> 00:02:39.000 Now, to face the monkey towards the light, it should be obvious now that all we need to do is select the negative y option instead. 24 00:02:39.000 --> 00:02:45.000 And that's it! Our monkey now faces the light no matter where the monkey or the light are in the scene. 25 00:02:45.000 --> 00:02:49.000 Feel free to play around with the other settings to better understand the constraint. 26 00:02:49.000 --> 00:02:53.000 But for the most use cases, this is all you'll need. 27 00:02:53.000 --> 00:03:04.000 Let's take a look now at the other related tracking constraints, that being the locked track constraint, the stretch 2 constraint, and the damped track constraint. 28 00:03:05.000 --> 00:03:11.000 Each of these is exactly like the track 2 constraint, but with some important differences. 29 00:03:11.000 --> 00:03:17.000 The locked track points an object towards a target object, but only along one axis. 30 00:03:17.000 --> 00:03:26.000 For example, by adding this to our monkey, you can see that it now can face the light, but will not look up or down, or tilt its head. 31 00:03:26.000 --> 00:03:35.000 The lock axis at the bottom of the locked track constraint refers to the only axis of the constrained object that should be rotating. 32 00:03:35.000 --> 00:03:48.000 The stretch 2 constraint works very similarly to the track 2 constraint, with the only main difference being that the object will actually stretch or contract based on the distance between the two objects. 33 00:03:48.000 --> 00:03:58.000 The object will stretch if it gets pulled past the location it was at when the constraint was applied, and contract if it gets pushed closer to the object that it is pointing to. 34 00:03:58.000 --> 00:04:06.000 You can, however, reset the scale of the object at any time with the reset button in the stretch 2 constraint settings. 35 00:04:06.000 --> 00:04:14.000 And volume settings help control how much the shape of the object should change as it stretches and contracts. 36 00:04:14.000 --> 00:04:23.000 The rest of these settings are typically fine if you leave them at default, however feel free to experiment further with these settings to better understand the constraint. 37 00:04:23.000 --> 00:04:31.000 The damped track constraint is very similar to the track 2 constraint, but removes the parameter for the up axis. 38 00:04:31.000 --> 00:04:37.000 Instead, it simply calculates the least amount of rotation needed to continue pointing at the target object. 39 00:04:38.000 --> 00:04:45.000 This allows it to feel more smooth compared to the track 2 constraint, but also gives you less control in the orientation of the monkey's head. 40 00:04:46.000 --> 00:04:49.000 Finally, we have the clamp 2 constraint. 41 00:04:49.000 --> 00:04:55.000 This is not exactly related to the track 2 constraint, but allow me to show you what I mean. 42 00:04:55.000 --> 00:04:58.000 Let's just go ahead and add it to our monkey head real quick. 43 00:04:58.000 --> 00:05:03.000 Seems simple enough. Let's add a target object like we have for all the others. 44 00:05:03.000 --> 00:05:10.000 Except that we can't. In fact, if we go to the drop down menu, you'll notice that our options are empty. 45 00:05:10.000 --> 00:05:15.000 That's because the clamp 2 constraint deals specifically with curve objects. 46 00:05:16.000 --> 00:05:23.000 But what are curves? Well, curves are smooth, math driven shapes that can be used as references for a variety of things. 47 00:05:24.000 --> 00:05:30.000 To see what they can do with the clamp 2 constraint, we can add a curve from the add menu under curve. 48 00:05:30.000 --> 00:05:33.000 Then select Bezier curve. 49 00:05:33.000 --> 00:05:39.000 Just to make things more clear, I'm going to scale this curve up a bit so it's large enough to see. 50 00:05:40.000 --> 00:05:46.000 From there, we can set this new Bezier curve as the target object of our clamp 2 constraint on our monkey. 51 00:05:46.000 --> 00:05:50.000 As you can see, the monkey immediately snaps to the curve's location. 52 00:05:50.000 --> 00:05:56.000 But if we try to move the monkey, you'll see exactly what the clamp 2 constraint really does. 53 00:05:57.000 --> 00:06:02.000 It clamps, or limits, the monkey's location to follow the curve. 54 00:06:02.000 --> 00:06:07.000 This can be very helpful when trying to keep an object on a certain path during animation. 55 00:06:07.000 --> 00:06:13.000 Checking cyclic will even allow the monkey to wrap around after reaching the end of the curve, 56 00:06:13.000 --> 00:06:18.000 and feel free to experiment with the axis options to better understand the constraint. 57 00:06:19.000 --> 00:06:23.000 These are the fundamentals of the tracking constraints in Blender.