Adobe After Effects Expressions Forum
reverse values
reverse values
by Luis Ozonas Ferrer on Aug 16, 2011 at 2:53:32 pm


I'm not used to expressions, if someone can help, I'd really appreciate!

I'd like to link a value from a plugin apllied to layer A, to the same parameter in layer B, but layer B has to do just the opposite.
I mean if the value in A is +2, link to B via expression to automatically set its value to -2.
I supose/hope this is from the basics!

The purpose is to apply aplugin blur in 2D layers alternatively so when a layer is sharpen th other is blurred and vice-versa, without going to camera focus distance. It has to be the plugin's blur.

Do my english the job to explain it correctly? apologizes if not..

Re: reverse values
by Dan Ebberts on Aug 16, 2011 at 4:38:44 pm

I think this expression for Layer B does what you're asking for, but I'm not sure it's what you want:

-thisComp.layer("Layer A").effect("Fast Blur")("Blurriness");

If what you really want is for layer B to have the inverse blur of Layer A, you have to define a maximum value. Then the expression for Layer B would look like this.

maxBlur = 20;
maxBlur-thisComp.layer("Layer A").effect("Fast Blur")("Blurriness");


Re: reverse values
by Luis Ozonas Ferrer on Aug 16, 2011 at 6:00:00 pm

Hi Dan

it works!
the second expression is just what I was looking for.

thanks so much!!!