If you connect two different properties using an expression, you may find that even after you change the value of an expression by multiplying by minus 1, the expression still does not do what you need it to do. In this movie, author Luisa Winters walks you through how to change the value of an expression.
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- The wiggle expression is perhaps the one that I use…the most in After Effects.…Wiggle will give you random values for a particular property…based on two parameters.…Frequency and magnitude.…Frequency is how many times per second…you would like for the values to change,…and magnitude is how much you would like…for the values to change.…So how often, and how much.…Let's go ahead and open composition 2.2,…changing the value of an expression.…
In here you're going to see two layers.…A column and a needle.…Let's go ahead and center this a little bit better.…I can select both of these and press U U…to see if there are any key frames.…And I don't see any so we're good.…If I scroll up the timeline you see…that nothing is happening.…Now, what I want to happen is that as the needle moves up,…I want the position of the needle to dictate…the height of the column.…
So as the needle moves up, the column will get taller.…As the needle moves down, the column will get shorter.…So let's go ahead and figure out how we're going to do that.…
- Adding expressions
- Editing expressions manually
- Changing expression dimensions: rate, value, music amplitude, etc.
- Working with expression variables
- Using the Expression Language menu
- Using random values