Scaling layers successively (linking scale values between layers)

Use expressions to scale objects successively and at precisely the same interval. This expression is useful for creating a concussion appearance, in which objects appear at a set interval and successively scale up and replace each other.


Linking scale values with a two-second delay between layers

To link scale values between three layers:

1. Position three layers in the center of the Composition window, from where they will stream in.
2. Create Scale keyframes for layer 3: set Scale to 0 at 0 seconds and 100 at 6 seconds.
3. Select the Scale property for layer 2 and choose Animation > Add Expression.
4. Drag the pick whip to the Scale property name of layer 3. The following expression appears:
thisComp.layer("layer name").scale
5. Add the "valueAtTime" function to the end of the expression to make layer 2 scale 2 seconds later than layer 3:
thisComp.layer("layer name").scale.valueAtTime(time-2)
6. Repeat steps 3 through 5 for layer 3, and add a valueAtTime (time -4) function:
thisComp.layer("layer name").scale.valueAtTime(time-4)
7. Preview the layer.