Expressions

Description
Expressions are quick scripts that can affect modify input values, from the expression itself or another object in AE, and then apply them to a specific Layer property. Expressions can be static throughout time or dynamicly changing as time progresses.

Adding an Expression
To Activate an expression:
 * 1) Select and expand the layer target layer's properties
 * 2) Locate a specific property, for example, scale
 * 3) hold down ALT and left click the little stopwatch near the property
 * 4) (notice the text box that appears where keyframes should go?)
 * 5) [[File:Activate_Expression01.JPG]]
 * 6) you can delete the default text and substitute a value of your own. 50 for example.

Try the following expressions [50, 50]

[50+10, 50-10] x=25; [50, x]

x=5; y=60; [x+y, x-y]

[random(1, 100), 100]


 * remember text values need "text" with quotations, while numeric values need numbers, Also if a property has 2 values, your expression should return 2 values as well.

Inputing Data from Other Sources
When using expressions you can use the data from another property or even another layer.

Example


 * 1) Using the steps above, activate the expression on a Layer's Opacity property.
 * 2) Now, Locate the little spiral button in the expression
 * 3) [[File:Pickwhip_Expression01.JPG]]
 * 4) scrub the timeline to see the effect over time

Advanced Expressions

 * 1) To see more expressions you can use the built-in library to help you pick and choose your expression.
 * 2) Locate the little arrow button just to the right of the pickwhip button mentioned above
 * 3) [[File:Library_Expression01.JPG]]
 * 4) Help->Expression Reference... ...for specific detail on what each expression does.

Resources

 * General tutorials
 * AEnhancers.com
 * scripts and expressions