After Effects Expressions

Chapter 7

Advanced Techniques

Triggers

Sometimes, you find a great Expression online—or you come up with one yourself—and it’s perfect except it starts too early. You don’t want it to affect the layer until 3 seconds have past. Or you want it to hold off until a layer keyframe-animates to a certain location. Or you want it to wait until a layer’s scale reaches a specific percentage. In all of these cases, you need a trigger: some event that launches an Experssion when you’re ready for it to be launched.

Split-Based Triggers

Or maybe not. Once you get into Expressions, there’s always the risk you’ll start overthinking everything. So before I delve into the nitty-gritty of triggers, let me whisper two simple words into your ear: split layers.