Creating 3D objects (new in CS6)

Now that After Effects has finished tracking and solving this scene, I've decided I want to put the poster on this side of the building. So I'm going to move my time indicator to a point where I had the clearest view of that surface. There's a few different ways to define what point in the 3D space you want to put your new layer to composite into the scene. One is just by moving the cursor over the Composition Panel while the 3D Camera Tracker is selected. If the Camera Tracker is not selected, your Track Points disappear. When it is selected, you get to see them and you get some interactive help in placing your points.

You need a minimum of three points to define a plane that After Effects will then place your new object on. As you drag your cursor between points, After Effects will automatically triangulate the three closest points and suggest those as possible places to create a plane. As you do so, look at the orientation of this bull's eye compared to the perspective of this actual scene. For example, down here the bull's eye looks like it's titled forward compared to that side of the building, so that would not be a good set of points to select.

However, something up here looks to have a better perspective compared to how the building is actually oriented. So this might make a good set of points whereas this trio obviously would not make a good set of points. So this is one approach that After Effects triangulate three points, click once and After Effects will select those three points as candidates to go ahead and create your new surface. Another approach is just to manually lasso a large number of points on the surface that you want to use.

After Effects will average together those points, throw out outliers that don't seem to agree with the other ones and again give you your target to work with. A third approach is to manually select the points yourself. Select one point to start, then Shift+Click additional points to define your plane, and select at least three. Points that are further apart create a more accurate plane. The closer they are the more of a chance you get a rogue tilt in your plane. Further apart, you will have a better orientation and you'll see this bull's eye looks like it's pretty well-oriented against the side of this building.

I tend to use a combination of these techniques. I'll select four apparently good points that are far apart and then hold the Shift key and lasso additional points in the core of that surface just to get more data to average together. Once you've done that you can hover your cursor over the bull's eye until you see this little four-headed arrow, which indicates you can move the bull's eye, move it to the center of where you want to place your new surface or your new layer.

I want to hang my poster pretty high in the side of this building so I'm going to choose around there. Another good habit to get into is to initially resize your bull's eye to roughly match the scale of the object you want to put on this layer. This is not so important if you're using no logic. It's more important if you're directly creating text. Neither case is a good habit to get into. Place your cursor over the center of the bull's eye, hold down Option on Mac or Alt on Windows and you'll see the cursor changes to a two-directional arrow. Scrub your bull's eye until it's roughly the size you want, in my case covering this side of the building, and I'll interactively reposition my bull's eye to center it and then resize it to make it cover that wall.

You can also resize your target over here in the Effect Controls Panel. Once you have a nice bull's eye target, right-click anywhere inside this ghosted white area that defines your new plane. Doing so will give you a list of options on what After Effects will create. Since I've not yet created a camera in the scene, all of my options will include, and Camera. But you see you can Create Text, Solid, Null or Shadow Catcher, which we will discuss a few movies from now, that based on the location of this bull's eye.

Or alternatively, you can create individual Text, Solid or Nulls for each of these points you have selected as opposed to the position of the bull's eye. In my case, I just need one layer, preferably a Null object, which I can then parent my poster to. So I'll select Null and Camera. You'll see a new Null object has been added to my scene as well as a 3D camera, which has been animated to match the camera's movement in this scene. I'll press U to reveals keyframes and you'll see After Effects is tracking its position, its rotation and its zoom in case the operator had a zoom rather than fixed lens and was altering the zoom during the course of this shot.

Now that we have a Null object in the scene, we can attach our own layers to it, and that's what we will do in the next movie.