There are many ways to control an animation using the tools that Adobe has provided in After Effects. In today’s tip, we’re going to take a look at three: keyframes, expressions, and a layer’s In Point.
Keyframing can work when you have a few complex animations to make that are not easily described by an expression. It also works when you wish to have direct control over an animation. The drawback, however, is when you wish to make any changes. If the changes made affect any major component of your animation, you may find yourself going back and tweaking every single keyframe. Multiply this over the number of tweaks you are likely to make to get something just right, and you can see where things might bog down. On the other hand, if you are working within very defined parameters, it might just do the trick!
Changing the In point of a layer, however, is useful for when you have a large number of layers of the same or similar type following a same or similar expression, and when you want to have precise control of exactly when the layers enter the comp. By creating your original layers with the appropriate effects, keyframes, and/or expressions, and then duplicating them as your needs require, you can have multiple instances of the same layer beginning at different points in your composition without the need to manually move keyframes or write complex expressions. To position the layer, simply click on the layer that you wish to position, and drag it to the time where you wish to see the layer begin.
To make things even more simple, put the Current Time Indicator (CTI) at the frame where you wish the layer to enter the comp, then click and hold the layer, press the shift key, and drag the In point near the CTI. The layer will then snap into place at the CTI.
See the animation attached to this post for an example of a comp using all three techniques listed above. The tree branch growth was made using keyframes on motion paths, the cherry blossoms were made using multiple instances of the same layer animated in by changing the layer’s In Point, and the breeze was made using a Wiggle Expression on distortion points using the Puppet Pin and Puppet Starch tools.