Twirl down any layer in the timeline, and you find the Transform controls. 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 Adobe decided to sort of grandfather it in here as an essential layer property; transforms has a snappier ring to it, evidently.
A property in After Effects is a data channel that you can find under a twirled-down layer. Typically the channel can be animated and has a stopwatch icon beside it which, when clicked, sets the first keyframe at the current time. That's 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 needle forward 24 frames, you could
And that's just an example of some of the things you could do with an added Position keyframe. There are options for causing the animation without setting a new Position value. You could also get that layer to transform 200 pixels over 24 frames by
If that's not crazy enough, you could even
The last two sets of options, in particular, are obviously designed for situations more complicated than the one I set up. Parenting is useful when several layers should all transform in the same manner, and expressions let you link just a single property or create one from scratch. 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 pre-compose.
Note that there are even many ways to enter values while animating: You can click and drag using the Selection tool (shortcut: V), the Pan Behind tool to move the anchor point (shortcut: Y), or the Rotate tool (shortcut: W, which the official documentation even points out is for "wotate"). But you can also work directly with the values found in the timeline, and you can do so by entering values or using the rub text feature. |