Join Todd Kopriva for an in-depth discussion in this video The 3D Camera Tracker, part of After Effects CS6 New Features Overview.
After Effects CS6 includes the new 3D Camera Tracker, which makes compositing elements into a seam of camera movement, much easier. Let's see how it works. In the compositing project, go to the Feature Section Final Composition, and do a quick Run Preview just to see how the scene looks. We have a simple side to side camera movement, so any objects that we composite into this scene need to follow that camera movement. In the Timeline panel right-click or Control click on Mac OS, and choose Track Camera.
The first step is analysis in the background. The fact that it's in the background means that we can do other things in After Effects while this is analyzing. We can interact with panels, go to another composition, do work, whatever you need to do. But this is only going to take a few more seconds, so, we'll just stay here for now. Notice that we can also interact with the properties of the effect itself, even while analysis is taking place. When analysis is done, the next step is solving for the camera movement.
And then, when the solving for the camera movement is done, what we'll see is a bunch of multicolored tracking points scattered all over the scene. Each of which is attached to a part of the scene. And it should be just about done. There we go. So select the effect to see the tracking points, and drag the current time indicator back and forth to see those points. So if you pay attention to a specific set of points. Like say these points here on the tires, notice that they stay stuck to the tire throughout.
One of the things that you can do at this point is look for any tracking points that are stuck to objects that are moving in the scene, as opposed to objects that are moving because of the camera. For example, this man running across the screen doesn't have motions that's because of the camera. So really the camera tracker shouldn't be worried about him. You can delete these points by right-clicking. Or Control clicking on Mac OS. Choosing Delete Selected Point. In this particular scene, we don't really need to worry too much about these.
But I just want to show you how it's done if necessary. You can delete more than one point at a time, such as these that are in this smoke from the explosion, by dragging around them. And then right-clicking or Control clicking on any one of the selected ones, and choosing Delete Selected Points. And as I said, you don't really need to worry to much about deleting these points in a scene like this, because a couple of extraneous points aren't really a big deal when you have so many good ones.
Now let's put an object in this scene. Let's start out with compositing a new scorch mark here on the ground. So with the effect selected I'll position the mouse pointer in the Composition panel. And here depending on where I put the mouse pointer various other track points become selected, and a little target shows up that shows where a solid or other layer would go if I added a solid with these tracking points.
So because we want to put new scorch marks here on the ground, I'll right-click here. And choose Create Solid In Camera. And we get a solid that sticks to the ground, matching the motion in the scene. Now, I don't actually want a turquoise layer, I want a black one, so I'll select the layer, just Ctrl+Shift+Y, to open the Solid Settings. Click the Color Swatch, and then bring Brightness down to zero to get a black layer.
And I will double-click on the layer in the Timeline panel to open it in the Layer panel, and then double-click on the Ellipse tool to create an elliptical mask. Press F to bring up the feather properties for the mask. Drag to really feather that quite a lot. I'll zoom out a little bit with the mouse scroll wheel. And I'll make this a little less perfectly circular. Then go back to the Composition panel, Deselect All. And let's move to opaque.
So I'll select the layer, press T for opacity. Bring that down to, say, 60%. And I'll change its blending mode. Now notice, I don't actually have a blending mode for this layer, because I'm currently using the Ray-traced 3D Renderer. So I will switch the renderer over to the classic 3D renderer so that I can use blending modes. And now I will set the blending mode to Overlay.
There. Now, I have, a new black scorch mark composited into my scene. Which is moving with the rest of the scene, just as if it were shot there originally. I'll delete this solid, and let's go back to the Ray-traced 3D Renderer, and composite some extruded 3D text into the scene. So with the effects selected I'll right click here, choose Create Text, and then in the Timeline panel select the text layer.
Press R for rotation. Change the X rotation to 90 degrees to make it stand up straight. I'll rotate it in a Y in a little bit as well. There. Now we have some text in the scene. Let's go ahead and extrude it. Go to the Geometry Options. For Extrusion Depth, make this say, 20. Give it a new Side Color.
I'll just sample a light gray from somewhere on the screen here. I'll zoom out just a little bit so we can see the entire scene. And now if I hit Run Preview, we have extruded 3D text that's composited into the scene. Just as if it was shot there. So you'll notice that we didn't even need to change any of the properties of the 3D Camera Tracker effect. But sometimes we might, so let's take a look at those. I'll close the text layer down.
Select the layer that has the 3D Camera Tracker effect, and let's look at some of these properties. We can chose a Shot Type, Fixed Angle of View, Variable Zoom, or Specify Angle of View. Fixed angle of view means you aren't zooming different amounts over the course of the shot. Variable Zoom means that there are different zoom values throughout the shot. And Specify Angle of View means that not only is it a fixed angle of view, but you know exactly what the angle is. If you simply leave it at Fixed Angle of View, After Effects will do its best to determine the angle, but if you know it, you can specify it. If you want to look at the 2D tracking points.
Which are the tracking points that are created in the first phase of analysis. You can choose 2D Source. The tracking points are normally just shown as a user interface element. Over the composition panel. But you can choose render track points also. Which actually renders the points into the image. One of the benefits of that is that you can see them as you do a Run Preview. Whereas, if render track points is not selected, we can see them as we're dragging through, but as soon as we click Run Preview.
To view the composition itself, they go away. Track point size, if the points are a little bit to small for you to see you can increase them, or if they're so large that they're getting in your way you can decrease them. Target Size refers to the size of the little bull's eyes here. So, if we increase this to something very large, notice that the bull's eyes that show where the layers will be placed get much larger as well. Put this back down to 100, and for Advanced.
Auto Detect is choosing between the methods. But if you know if the shot was shot with a pan on a tripod, you can tell After Effects and it makes it more likely that After Effects will be able to do a good solve. Similarly, if you know that the scene is mostly flat, typical is what was used in the scene that we just analyzed, as you can tell here. Auto Detect is the method that was chosen here, and then After Effects chose to use typical.
Average Error refers to the average difference between the placement of the 2D tracking points and a reprojection of the 3D tracking points onto the 2D scene. A smaller value is better, but if you do something such as manually delete a lot of good tracking points, you can have a low error and still end up with a bad result. Detail analysis is exactly what it sounds like, if you check this then After Effects will be more precise in the analysis, but it will take a much longer time. And Hide Warning banner will hide the banner that tells you that a scene needs to be reanalyzed. I think that you'll find that, very often, you don't need to worry about any of these properties.
And in fact, you can very often do as we did at the beginning of this video, which is to simply, do an analysis, accept the defaults, and place your layers in the scene without any fuss.
- 3D animation
- User interface changes and removed features