Animation Methods

Twirl down any layer in the Timeline, and the Transform controls are revealed. On a typical layer, transforms are spatial data related to Position and its cousins Anchor Point, Scale, Rotation, and, um, Opacity. Opacity isn't really spatial transform data, but apparently Adobe decided to sort of grandfather it in here as an essential layer property; and "Transforms" evidently has a snappier ring to it.

  • The keyboard shortcuts to reveal individual transforms are the first letter of each type: P, A, S, R, and, um, TOpacity is the oddball again, because O is already in use as the Out point of a layer (mentioned above).
  • To reveal additional properties, hold down Shift when typing the letter shortcut; you can also toggle a property to hide in this manner.

A property in After Effects is a data channel found in a twirled-down layer. Typically a property can be animated and has a stopwatch icon beside it which, when clicked, sets a keyframe at the current time.

That by itself is simple enough. But there are, in fact, many different ways to animate a property in After Effects. How many can you think of? As an example, if you wanted to move a layer 200 pixels along the X axis over 24 frames, after setting the first keyframe and moving the time indicator forward 24 frames, you could

  • Drag the layer to the new position in the Composition panel (with the Shift key held down, constraining it to one axis)
  • Shift+Right Arrow 20 times to move the layer exactly 200 pixels
  • Enter the new value by highlighting the X Position numerical value and typing in the new number
  • Drag the X Position numerical value to the right until it is 200 pixels higher (perhaps holding down Shift to increment it by ten pixels)
  • Enter a numerical offset by highlighting the X Position numerical value and typing +200 (as was done with time, above)
  • Copy and paste the Position keyframe from another layer, or another point in time (assuming there is a keyframe with the needed Position value)

And those are just the options to keyframe that one property. You could also create the animation without key-framing a new Position value, and transform the layer 200 pixels on the X axis over 24 frames by

  • Keyframing an anchor point offset in the opposite direction (negative 200 pixel X value) over 24 frames
  • Enabling 3D for the layer, adding a 50mm camera, and animating the camera moving 200 pixels, again in the negative X direction
  • Parenting the layer to another layer that has the transform
  • Replacing the layer with a composition that already contains the layer and transform
  • Assigning an expression to the Position channel that performs the animation without keyframes

Notes

Don't worry, you're not going to be tested on these. But you can understand that there are many approaches to a given problem in After Effects, and the more of them you know, the more prepared you'll be for whatever comes your way.

If that's not crazy enough, you could even

  • Apply the Transform effect to the layer and animate the effect's Position value
  • Animate in real time via the cursor using Motion Sketch (I did say "crazy")
  • Paste in a path (perhaps using a Mask or a Path from Photoshop or Illustrator) to the Position channel, adjusting timing as needed (this method defaults to creating a two-second animation)again, crazy, but possible

Notes

The Transform effect exists for one reason only: to allow you to change the order in which Transforms occur. Normally, they occur before all effects, but this plug-in lets them occur after an effect is applied as well, without the need to precompose.

The last two options, in particular, are clearly designed for other, more complicated situations. Parenting is useful to transform several layers in the same manner, while expressions link two animations together, or create one from scratch.

Note that there is even a variety of ways to enter values while animating. You can

  • Drag with the Selection tool (shortcut: V)
  • Drag the Pan Behind tool to move the anchor point (shortcut: Y)
  • Drag the Rotate tool (shortcut: W, which the official documentation even points out is for "wotate")

Tip

When dragging text in the Timeline or Effect Controls, hold down Shift to increment values at ten times the normal amount, or hold down Ctrl+Alt (Cmd+Option) to increment at one tenth the normal amount. The "normal amount" is typically, but not always, 1 for any given property; it depends on the slider range, which you can edit by context-clicking on the value in Effect Controls and choosing Edit Value.

But you can also work directly with the values found in the Timeline, and you can do so by highlighting and entering values, or by dragging on them without highlighting.

Keyframes and The Graph Editor





Adobe After Effects 7. 0 Studio Techniques
Adobe After Effects 7.0 Studio Techniques
ISBN: 0321385527
EAN: 2147483647
Year: 2004
Pages: 157
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