[Anthony Diehl]

Sweet, thanks. I played around with this method. Could;t get it working, but thats probably because I’m just super new to building out longer expressions.

I did manage to find a method that worked by piecing together a few other examples I found.


target = thisComp.layer("Expand");
alpha = target.sampleImage(transform.position, [width, height]/2, true, time)[3];
ease(alpha, 0, 1, 0, 100)

I have a pre-comped layer (“Expand”) that has a variety of masks, ramps, etc. I am sampling the alpha value on that layer and putting this expression in to control the scale value of the Transform effect on about 150 small layers which are arranged in a big grid. Its kind of slow to render but otherwise works great. I can get some cool effects and really complicated patterns going by just tweaking my “Expand” layer.

Thanks for the feedback.

[Anthony Diehl]

Thanks for the reply! Ya, I have another similar comp that is using this method to recolour a bunch of layers based on another layer that is sampled. It works great, but I just copy and pasted some script I found online.

How exactly would I use sampleImage to get usable data that I can then link to an effect parameter?
I guess I want to look at luminosity or alpha somehow, yes?

I’m really green when it comes to expressions like this. ANy examples of expression code that would work?

thanks!