Need help with thousands of layers - a better way?

[philshowNYC]

Hello all. I have a puzzle and could use an idea.

i have a composition with thousands (almost 7000) of small circles - each its own layer. the design intent is to create a twinkle effect using each circle as a single pixel. I am trying to treat each circle as a single pixel and change the opacity based upon a single pixel in a second composition. I am currently using an expression to find the axis pixel of the circle and locate the brightness of a corresponding pixel in the second composition, and then set the opacity of the circle layer in the main composition.

Also my comp is 8000x4000. All of this is needed for an elaborate video production event - the circles map to exact pixels on a video display and cannot move. 

this is getting unweildy. so many layers starts bogging down the powerful mac that i have. Also, now if i want to go back and edit the expression, Id have to do it thousands of times.

- Is there a way to have a global 'function' or expression and then be able to tweak it once?

- Can anyone think of another way to accomplish this in a different way?   

Attached is a portion of the comp for illustration. Thank you all.

[Mylenium]

There's all manner of scripts to bulk-edit expressions on AEScripts.com. Also the built-in copy&paste functions for property links or expressions only in AE will work on all selected layers. The rest is too unspecific. From setting up clever combos of sliders and other expression controls to parsing text on another layer as script code there's any number of ways to get expressions to respond to external inputs, but of course some of that stuff requires certain prerequisites as well beyond abusing the eval() function or referencing another layer. Without any specific info on what exactly needs to be done beyond your blinking stars nobody can tell you more than that. For me that would be a ten minute project starting from scratch, but of course even adding some seemingly simple requirement could inflate this to spending hours figuring out the code.

Mylenium

[Mathias Moehl]

My (paid) extension Automation Blocks for Ae comes with handy tools to apply an expression to many properties at once and do things like search & replace in expressions:

https://docs.mamoworld.com/automation-blocks/tools-ae/expressions

You could even create a custom block script with Automation Blocks, which creates a shape layer with lots of circle shapes and applies a custom expression to each of them. This would require to dive deeper into Automation Blocks, though. This tutorial gives you an idea how to create layers and shapes with Automation Blocks:
https://docs.mamoworld.com/automation-blocks/tutorials-ae/programmingAHighlightTool

These kinds of automations can be very handy if you want to create hundrets of layers (or shapes on a layer) and then do little individual changes in the expressions or values of each of them.

[Mathias Moehl]

In this tutorial I show how to share the same code among many expressions using a jsx file: