Adobe After Effects - Basic Animation

In the last issue, I introduced Adobe After Effects as a tool for editors. This time, we’ll work through our first exercise, which will help you understand the program’s basic functions and animation controls.

After Effects is designed around a layer-based timeline (as opposed to the track-based timeline found in editing programs), which means that it treats each clip or piece of artwork as a separate object that exists in its own layer, with its own set of properties. This exercise will illustrate this point, as we take two still images — an airplane and some clouds — and animate them so that the airplane flies across the sky.

If you’d like to try out the examples in this article yourself, click here to download the necessary materials:

The images for this exercise are in Targa format, the most common cross-platform image format for visual effects. If you have Adobe Photoshop on your system, use it to open and examine the images. (While it’s not essential to have Photoshop in order to work with AE, it’s very helpful, and the two programs work together seamlessly.) Examine the Channels Palette. You’ll notice four black and white images, one in each color channel: red, green, blue and a composite channel with all the colors combined. For the airplane.tga file, there is an additional channel called “alpha 1.” This tells AE what part of the image is transparent. The black area in the channel represents the transparent area, and the white area represents the opaque area.

Open After Effects. You should be looking at a blank project window. The first step in any AE project is to import source footage. The simplest way to do this is to drag and drop the items from the desktop into the Project Window. But for more control, let’s import our footage by navigating the menus.

Save your project to the same location as the source files you’ve imported. Remember that AE does not copy the image data into the project file. It simply creates a reference link back to the source material on the hard drive. If you rename or delete those files after importing them into your project, you can run into trouble, because AE won’t be able to locate them.

Figure 1. The Footage Window,
showing the Clouds file image.

Let’s examine the footage. In the Project Window, double-click on the clouds.tga file. The image will open in an AE Footage Window (see Figure 1). At the bottom right are four colored buttons — red, green, blue, and white — which correspond to the image’s channels.

Go back to the Project Window and double-click the airplane.tga file. It will open in its own Footage Window, tabbed with the Footage Window for the clouds file (see Figure 2). To view the two windows simultaneously, click on one of the tabs and drag it away from the other.

Figure 2. Two images tabbed together in the Footage Window: Clouds and Airplane.

Close the Footage Windows. In the Project Window, single click either of the files. In the top portion of the Project Window, you will see a thumbnail image and information about the item you selected, including its dimensions in pixels — in this case, 320x240 (see Figure 3). It’s important to know this, because the resolution of the source footage determines how high we can make the resolution of our final movie.

Figure 3. The Project Window. A new compo-sition appears along with
the footage files.

To animate or make a movie, you need to create what AE calls a composition. Select “New Composition” from the Composition menu. You will be presented with the Composition Settings dialog box. Input the following:

A blank Timeline and Comp Window will appear. The composition you just created now appears in your Project Window, along with the source footage files.

You now need to place the source footage into the composition. There are several ways to do this. One quick way is to work entirely within the Project Window and just drag and drop the source image files on top of the comp file. Try this by dropping the clouds.tga file on top of the airplane comp. The clouds image will then appear both in the Comp Window and as a layer in the Timeline.

Another way to add footage to a comp is to drag it from the Project Window into either the Composition Window or the Timeline Window. (When you drag the footage into the Comp Window, you can position it anywhere you want in the frame; when you place the footage into the Timeline Window, its image will appear perfectly centered in the Comp Window.) Drag the airplane.tga file from the Project Window into the Timeline Window.

Figure 4. The Comp Window, scaled so that the viewable part of the image is surrounded by gray work area. When material is
positioned outside the composition’s viewable area
it is visible only as a white bounding box.

In the Timeline, the clouds layer appears below the airplane layer, because we added the clouds layer to the composition first. That means that in the Composition Window, the airplane layer appears in front of the clouds, because higher layers appear in front of lower ones. You can rearrange layers in the Timeline by dragging and dropping them.

The Composition Window shows what is visible in your composition, as if you were looking



Figure 5. The Toolbox Palette. The arrow in the upper left corner is the Move tool.

through a camera lens. Using the zoom ratio popup in the lower left of the Comp Window, zoom out to about 50%, and you will see a gray area around the viewable frame. This is your workspace— the off-camera area (see Figure 4).

We will now animate the movement of the airplane. This is done through the use of keyframes, which represent the value of a property at a point in time. This works in the same way that you’re probably familiar with from the Avid: if we make two keyframes with different sets of values, AE will dynamically change the values as it moves from one to the other.

Click the little triangle to the left of the airplane layer name in the Timeline Window (see Figure 6). It will open to reveal three groups of layer properties: Masks, Effects and Transformations. Each layer in an AE composition has its own set of properties, and each of these properties has yet another little triangle that you can open to expose more information. Unlike in the Avid, where properties are controlled and key frames are created in Effect Mode, in After Effects all controls are applied in the Timeline itself.

At the moment, there is nothing under either Masks or Effects, because these properties have to be applied before any attributes will appear. We’ll worry about that in a later lesson, but for now, let’s focus on the group of properties we see when we click on the triangle next to Transform.

Figure 6. The Timeline Window. The Transform layer is opened,
revealing the Basic Properties.

These are the basic properties: Position, Rotation, Scale, Anchor Point, and Opacity. All picture layers have this same set of basic properties. As you can see in Figure 6, to the right of each property name is a numeric value with a dotted line under it. Until we set keyframes to plot animation, these values will remain constant over time.

We are going to animate the airplane layer by using the Position attribute to move the layer past the camera from left to right. To do so, we must first initialize keyframing for the airplane layer’s Position property. To do that, click the tiny stopwatch icon to the left of the property name (see Figure 7). A basic keyframe, which looks like a little diamond, will appear on the Timeline.

Figure 7. Animating a simple move. After keyframing is initialized, changing the layer’s position in the Comp Window automatically sets a new keyframe
in the Time Layout Window.

You only need to click the icon once; after you have initialized keyframing, every time you change the property’s value at a new point in time, AE will automatically set another keyframe, and another little diamond will appear. Be careful, though — if you click the stopwatch icon again after you initialize keyframing, it will remove all the keyframes you have set for that property.

You’ve already placed the airplane layer off camera to the left of frame; this will become the starting position for its animation. To move the airplane, you will go forward in time and set a second keyframe at the airplane’s ending position. The simplest way to navigate time is to drag the Time Marker bar (the vertical line with a triangle on top) along the Timeline (see Figure 7). You can also enter a time value numerically by clicking on the time display in either the Timeline or Comp Window. This will bring up the Go To Time dialog box. Enter a value of 300, which represents three seconds and zero frames in SMPTE time code. The Time Marker will jump to the new time.

In the Composition Window, drag the airplane layer across camera, positioning it off camera to the right. Notice that a second keyframe is automatically set on the Timeline in the Position attribute of the Airplane layer. Once you’ve moved in time, changing any attribute will automatically create a new keyframe (see Figure 7).

Figure 8. The Time Controls Palette,
used to play back the composition.

You’ve now created your first AE animation. To preview it, use the Time Controls palette. (If you don’t see the palette, select Show Time Controls from the Window menu). The buttons should be self-evident (see Figure 8). Hit play and watch the airplane fly across the sky!

You can experiment by adding more position keyframes to change the shape of the motion path between the airplane’s starting and ending point. Or try setting keyframes for scale and rotation to change the shape and orientation of the plane as it moves.

When you want to turn your project into a stand-alone movie that you can view independently of the source footage, you are ready to render.

A finished movie file will be created on your drive. On a Mac, this will be a QuickTime file; on a PC it’ll be an AVI file. A simple double click will play it. On the Mac, it will open in the Quicktime player; on the PC, in the Windows Media Player.

In the next issue, we’ll move beyond still images and begin working with video.