That is too many layers. YOu'll have to simplify your AI document. You are going to run into a lot of problems with a comp with that many layers. One of them is a display bug when you get over a certain number of layers.
I've done some awfully complicated composites and graphics animations. I can't imagine a single comp with 1500 layers. I'd never make a deadline unless I simplified the project into manageable pieces.
Thanks to your kind advice. Unfortunately I need that layers to build my animation since I can't figure out how to solve it in a smart way.
Ps. The animation is to flip all the pixels to form a map. Neither effect and plugin can do it in the way I want it to be.
Build it in sections...
Card Dance? Card Wipe? Trapcode Form.
You'll go nuts trying to do this with a bunch of layers in illustrator. I think I have visualized what you want. If it were me I'd use Card Dance and a gradient. 3D flipping of small squares - not often used but extremely powerful and very quick to render. Here's some of the basics including some tracking with Mocha....
Even more complex would be Trapcode Form:
Here's a tutorial from Red Giant:
As many particles and as many shapes as you want flying around in minutes instead of days.
BTW, I have vetted these tutorial sources, both of the instructors know what they are talking about. You have to be very careful when you search YouTube for tutorials because most of them are delivered by folks with very little experience and offer little help that will do you good in the long run.
Actually I'm stuck in an awkward situation where I'm forced to use a map that built from pixels at first. This give me issue to use card wipe, dance, or even trapcode.
Anyway, I'll give it a try to Form and see how far can I go. Thanks and have a nice day, Sir.
Food for thought:
If your system isn't responding, then that's a firm sign that it can't handle the workflow of a AI with 1,500 layers.
Does each layer need to animate separate from the other?
Import the map as a single layer - footage.
If you need to assemble the map then you can use a custom shatter map and a gradient to control the shatter, then pre-compose and time remap and bingo your map is assembled from pieces as little as 4 pixels square.
There are a zillion ways to do this that are way more efficient than creating 1500 + layers in Illustrator.
It would really help if we had a better idea of exactly what you are trying to accomplish. I've used Shatter a bunch of times to make maps and charts form from what appear to be particles. It just takes a few minutes to set up the composition.
How did you end up solving your issue? We are curious! If you still need help, also let us know.