Expressions are FUN!
Expressions are FUN!
by Ben Unguren, Graphics Designer at FS3 graphics, Provo, Utah, USA
©2001 Ben Unguren. All Rights Reserved. Used at CreativeCow.net by kind permission of the author.
In this tutorial, Ben Unguren will show you one way to control expressions in Adobe After Effects 5, by using another layer as a "controller" of a layer with a simple wiggling expression, giving you a great deal more control. If you are unfamiliar with expressions in After Effects 5, you may want to read the chapter "Creating Expressions" in the After Effects 5.0 manual before continuing with this tutorial.
CLICK HERE TO SEE A SAMPLE MOVIE
Click here to download the project files
Part One: Setting it All Up
(this part shouldn't take too long--we're not picky here)
We are going to make two solids: one invisible ("WIGGLE_CONTROL"), the other with the text "wiggle" in it ("wiggle"). If you know how to do this, go ahead and do it and skip on to Part Two below.
Make a new composition, size 320x240 and a duration of at least 10 seconds.
Make a solid, same size as the composition. Name it "wiggle".
Apply the "Basic Text" effect to the "wiggle" layer.
Type in "WIGGLE" or something else just as silly, choose a happy font, and click OK.
anti-alias the layer (so it looks decent while we work with it)
Adjust the effect settings until you have something terribly happy:
Click on the image above to see a larger image
Make a second layer, name it "WIGGLE_CONTROL", and turn off it's visibility.
End of set-up
Part Two: Making the Basic Wiggle Expression
We are going to write an expression for the 'wiggle' layer that will make it... well, wiggle.
With the "wiggle" layer selected, press the 'p' key to bring up the position attribute.
Make an expression for wiggle's position, by selecting Animation-->Add
(you can also option-click on position's stopwatch to do the same thing)
The basic expression appears for position:
Open the language elements menu (by clicking the little box next to the pick whip with the arrow pointing to the right). Select Property-->wiggler(
The start of the wiggle formula appears:
In After Effects the formula for the "wiggle" feature is understood as follows:
wiggle(freq, amp, octaves=1, amp_mult=.5, t=time)
SIDE NOTE: When the formula reads something like "octaves=1", that means that if you don't enter a value for octaves, one (1) will be the default. If you're confused, stay with it. Suddenly it will all make sense and change your life forever.
EXPLANATION OF THAT THING ABOVE:
- freq stands for frequency, and is measured in wiggles per second. The higher the number, the FASTER it shakes.
- amp stands for amplitude, and determines how LARGE the wiggle is. the bigger the number, the greater the area the wiggle is going to cover.
- the other attributes we'll just leave at their defaults. (since only the first two don't have defaults, we only have to worry about them, but take time to experiment with all the variables)
- THESE EXPLANATIONS ARE IN THE AE 5.0 MANUAL, so check there for more information (page 336 to be precise).
In order to avoid getting an error message, we have to make a formula that works, which can be met (minimally) by entering frequency and amplitude. We will enter it as follows:
Why did I add 'position' before 'wiggle'? Because the book told me to! If it doesn't work, CONSULT THE BOOK! (AE 5.0 Manual, page 336)
If you're checking out the expression and are still getting an error message, re-examine your formula. It should work. However, computers are very picky and want the thing written exactly as they should be.
RAM PREVIEW your comp. The text should be wigglin'
Go to Part Three: Setting Up the Other Layer
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