Wiggle(.5,20) will adjust the position value by 20, 0.5 times per second. Wiggle randomizes the value of that property by the amplitude defined at the rate defined.

So the above expression could look like this: While we're at it, it's also good to know that paragraphing doesn't matter. After cleaning things up like this (especially for Radial Scan), things were a lot easier. I remember when I was creating the Linear Scan animation preset I had so many reference values in my expressions that when I got tired I couldn't fix problems anymore. Also, if I wanted to change Offset to a different slider, all I have to do is select the Offset variable and just pick-whip the new variable that I want. If ever there should be an error anywhere in the expression, or if we need to change anything, we can do it very easily.

Reference=thisComp.layer('Null 1').opacity Offset=thisComp.layer('Null 2').effect('Offset') Divider=thisComp.layer(Null 2').effect('Divider')('Slider') This can look a lot cleaner if we did this: (thisComp.layer('Null 1').opacity + thisComp.layer('Null 2').effect('Offset')('Slider'))/thisComp.layer('Null 2').effect('Divider')('Slider') They are mostly useful for cleaning up your expressions. Variables are basically sets of words that you assign values for. To place an expression, just ALT-CLICK on the stopwatch! Keep in mind you can still apply keyframes. Though sometimes it does get out of hand.

After effects expressions opacity flash