{
    var comp = app.project.activeItem;
    if (!(comp instanceof CompItem)) {
        alert("Please select a composition.");
    }

    app.beginUndoGroup("Create Solids for Nulls with Opacity Check");

    // Collect all null layers
    var nullLayers = [];
    for (var i = 1; i <= comp.numLayers; i++) {
        var layer = comp.layer(i);
        if (layer.nullLayer) {
            layer.name = "TackedNull_" + i;
            nullLayers.push(layer);
        }
    }

    var total = nullLayers.length;

    // Add progress text layer
    var progressText = comp.layers.addText("0 / " + total);
    progressText.enabled = false;
    progressText.moveToBeginning();

    // Loop through stored nulls and create solids
    for (var j = 0; j < nullLayers.length; j++) {
        var nullLayer = nullLayers[j];

        // Update progress display
        progressText.name= j + " / " + total;

        // Create solid
        var solid = comp.layers.addSolid([1, 1, 1], "Solid for " + nullLayer.name, 64, 64, comp.pixelAspect);
        solid.moveBefore(nullLayer);

        // Expression to follow the null's position in comp space
        var posExpr =
            "thisComp.layer('" + nullLayer.name + "').toComp([0,0,0]);";
        solid.property("Position").expression = posExpr;

        // Expression to sample alpha from the first layer at solid’s position
        var opacityExpr =
            "alpha = thisComp.layer('Roto Matte').sampleImage(transform.position, [width, height]/2, true, time)[3]\n" +
            "alpha > 0.2 ? 100 : 0;";
        solid.property("Opacity").expression = opacityExpr;

        solid.scale.setValue([250, 250]);

    }

    progressText.remove(); // Remove the progress text layer after completion

    app.endUndoGroup();
}