Ordre aléatoire des calques

Tu peux utiliser un script:

var proj = app.project;
var thisComp = proj.activeItem;
var layers = [];
for (var i = 1; i <= thisComp.numLayers; i++) {
    layers.push(thisComp.layer(i));
}
for (var i = layers.length - 1; i > 0; i--) {
    var j = Math.floor(Math.random() * (i + 1));
    var temp = layers[i];
    layers[i] = layers[j];
    layers[j] = temp;
}
for (var i = 0; i < layers.length; i++) {
    layers[i].moveToBeginning();
}