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Activity Forums Adobe After Effects Expressions Using a layer as a boundary for other layers

  • Using a layer as a boundary for other layers

    Posted by Shane Shornock on October 25, 2023 at 1:32 pm

    Hello all, I have a design that requires that I put photos of people in the state they are from. I have 800 photos in total, and I wonder if I could create a script that takes selected layers, places them on top of a layer of a state, and organizes them in a grid whose boundary is the state.

    Shane Shornock replied 4 months ago 2 Members · 3 Replies
  • 3 Replies
  • Tom Morton

    October 25, 2023 at 3:06 pm

    well anything is possible… but you haven’t given much information. Do you have a database of which photos are part of which state? Are the photos names randomly or can the names be used to define where the photo goes. If you have a database, what format is it in? If you don’t have a database, what could the script use to determine which photo / layer goes on which state?

    Also, just to be sure… how is this video related, ie why do you need After Effects? If it’s a static image, I would lean towards, Indesign or Illustrator, but you haven’t described whether there’s some animation involved or anything? Any animation or movement would also affect how the script operates.

    Let us know!

  • Shane Shornock

    October 25, 2023 at 5:35 pm

    I am attaching an example from last year’s video I created. Each state has people who represent it. I was able to use ChatGPT and get what I wanted. I don’t know if anyone wants to improve on it. I am also attaching the video of the script working and I will attach here the script

  • Shane Shornock

    October 25, 2023 at 5:36 pm

    if (app.project.activeItem.selectedLayers.length < 2) {
    alert(“Please select the boundary layer and at least one layer to adjust.”);
    } else {
    var comp = app.project.activeItem;

    // Assuming the first selected layer is the boundary layer
    var boundaryLayer = comp.selectedLayers[0];
    var boundaryRect = boundaryLayer.sourceRectAtTime(comp.time, false);

    // Calculate the number of rows and columns
    var numLayers = comp.selectedLayers.length – 1; // subtract 1 for the boundary layer
    var numRows = Math.ceil(Math.sqrt(numLayers));
    var numCols = Math.ceil(numLayers / numRows);

    var xOffset = boundaryRect.width / (numCols + 1);
    var yOffset = boundaryRect.height / (numRows + 1);

    var currentRow = 1;
    var currentCol = 1;

    // Loop through the other selected layers and position them in a grid
    for (var i = 1; i <= numLayers; i++) {
    var layerToAdjust = comp.selectedLayers[i];
    var layerRect = layerToAdjust.sourceRectAtTime(comp.time, false);

    // Calculate the scale factors for width and height
    var scaleX = (xOffset / layerRect.width) * 100;
    var scaleY = (yOffset / layerRect.height) * 100;

    // Use the smaller scale factor to ensure the layer fits inside its grid cell
    var newScale = Math.min(scaleX, scaleY);
    layerToAdjust.scale.setValue([newScale, newScale]);

    // Position layer in the grid
    var newX = boundaryLayer.position.value[0] – (boundaryRect.width / 2) + (xOffset * currentCol);
    var newY = boundaryLayer.position.value[1] – (boundaryRect.height / 2) + (yOffset * currentRow);
    layerToAdjust.position.setValue([newX, newY]);

    // Move to next position in the grid
    if (currentCol > numCols) {
    currentCol = 1;

    alert(“Layers adjusted to grid successfully!”);

    // Create an undo group for this action
    app.beginUndoGroup(“Create Null and Parent Selected Layers”);

    // Get the active composition and its selected layers
    var comp = app.project.activeItem;
    var selectedLayers = comp.selectedLayers;

    // Create the null object
    var nullLayer = comp.layers.addNull(); = “Parent Null”;

    // Parent the selected layers to the null
    for (var i = 1; i < selectedLayers.length; i++) {
    selectedLayers[i].parent = nullLayer;

    // End the undo group


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