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Activity Forums Adobe After Effects Expressions Cluster positions of text layers according to luminosity of a matte layer.

  • Filip Vandueren

    March 7, 2022 at 12:39 pm

    In theory, yes.

    But we’re talking about hundreds (thousands ?) of layers each with an expression on position that needs to sample another layer.

    This quickly becomes unworkable, especially if you expect to also be animating it.

    It could be baked in with a script, so the expressions don’t have to keep evaluating, but I would look into a Particle System, (or maybe Motion Boutique’s Pastiche ?) to do the heavy lifting for you.

  • Christopher Hesse

    March 8, 2022 at 2:24 pm

    Uh – interesting! I’ve never heard of Pastiche before, but that’s a spot on recommendation! Thanks a lot!

  • Filip Vandueren

    March 8, 2022 at 5:03 pm

    Can you tell me how you will want to animate the image ?

    If you just want to slowly build up the final image, then I have a method that’ll work in after effects:

    (animated here:)

    View post on

  • Christopher Hesse

    March 9, 2022 at 11:36 am

    Yeah, that’s pretty much what I’m trying to accomplish. I’ve already found a way, but I’d like to see if your way is better, if you’d like to share 🙂

  • Filip Vandueren

    March 10, 2022 at 8:23 am

    Damn… I spend a lot of time doing a write-up to explain the whole expression and project, posted the reply and now I see it didn’t post to the site…

    Here’s the project-link again:

    let me know if you want some clarification on the process.

    This is something which would probably be much faster to code/render in Processing or P5 I believe, although I getr about a 2FPS render time (6 minutes for 1800 frames of build up) which is OK-ish

  • Christopher Hesse

    March 10, 2022 at 9:55 am

    Dude, your project feels like trying to read hieroglyphs without the rosetta stone to me :D. All I can glimpse is that it’s awesome! But this thing works without any plugin like Pastiche, correct?

  • Filip Vandueren

    March 10, 2022 at 11:21 am


    Pastiche organizes dozens/hundreds of layers into a pattern based on another layer’s brightness or alpha, But it does it in a “harder” way

    This method moves around a handful of layers randomly, but with a higher probability of them winding up at “dark” patches of the reference image. It’s the CC Time Blend Effect that actually “builds” the final image by accumulating all previous frames (like Echo, but faster and with less memory)

    But in the end you only wind up with just the “afterimage” of what the layers made, not actually thousands of layers.

    The final frame of my example movie has I believe the equivalent of 28.800 layers of text.

    But you can’t then animate the layers to somewhere else for example. That would take thousands of “actual” layers, and it would probably kill After Effects or your CPU 🙂

  • Christopher Hesse

    March 10, 2022 at 12:23 pm

    Yeah, I figured out as much. Time Blend set to 100 % acts like sort of a permanent Echo. Still – insanely cool :).

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