Essential After Effects Expressions List

// --- Wiggle Controls ---
var frequency = 2;   // Wiggles per second (e.g., 1 for slow, 5 for fast)
var amplitude = 50;  // Max amount of change (e.g., 50 pixels for position)
var octaves = 1;     // Optional: Layers of detail in the wiggle (usually 1-3)
var amp_mult = 0.5;  // Optional: How much an octave affects amplitude (0 to 1)
var timeToWiggleAt = time; // Optional: Base time for wiggle (default is current time)

wiggle(frequency, amplitude, octaves, amp_mult, timeToWiggleAt);

// --- LoopOut Example (applied after last keyframe) ---
var loopType = "cycle"; // "cycle", "pingpong", "offset", or "continue"
var numKeyframesToLoop = 0; // 0 means all keyframes, 1 means segment between last two, etc.
loopOut(loopType, numKeyframesToLoop);

// --- LoopIn Example (applied before first keyframe) ---
// loopIn(loopType, numKeyframesToLoop);

// Basic time usage (returns current time in seconds)
time;

// Example: Continuous Rotation (apply to Rotation property)
var rotationSpeed = 90; // Degrees per second
time * rotationSpeed;

// Example: Constant Horizontal Movement (apply to Position property)
var initialX = value[0]; // Or a specific starting X value like 100
var speedX = 200; // Pixels per second
[initialX + time * speedX, value[1]]; // Keeps original Y

// Example: Add a small wiggle to existing keyframed position
value + wiggle(0.5, 15);

// --- Delayed Follow Example (apply to Position property of follower layer) ---
var leaderLayer = thisComp.layer("LeaderLayerName"); // Change "LeaderLayerName" to the name of your leader layer
var delayInSeconds = 0.5; // How much time delay

leaderLayer.transform.position.valueAtTime(time - delayInSeconds);

// Example: Staggered Opacity for duplicated layers
var baseOpacity = 100;
var opacityDecrementPerLayer = 10; // Each layer below will be 10% less opaque
baseOpacity - (index - 1) * opacityDecrementPerLayer; // (index-1) so first layer is full opacity

// Example: Control Wiggle Frequency with a slider named "FreqControl" on this layer
var freq = effect("FreqControl")("Slider");
var amp = 50; // Amplitude can still be fixed or linked to another slider
wiggle(freq, amp);

// Example: Y Position sine wave movement
var initialY = value[1];       // Initial Y position of the layer
var amplitude = 50;          // How high/low the wave goes (pixels)
var frequency = 2;           // How many full cycles per second

var yPositionOffset = Math.sin(time * frequency * 2 * Math.PI) * amplitude;
[value[0], initialY + yPositionOffset]; // Keep original X, animate Y

// Example: Random opacity per layer that stays consistent
var minOpacity = 20;
var maxOpacity = 80;
seedRandom(index, true); // Seed with layer index, timeless makes it fixed per layer
random(minOpacity, maxOpacity);

// Example: Random opacity that changes every frame (no seedRandom or timeless=false)
random(20, 80);

// Example: Scale from 50% to 100% between time 0 and 2 seconds, with S-curve easing
var startScale = 50;
var endScale = 100;
var startTime = 0;
var endTime = 2;
var s = ease(time, startTime, endTime, startScale, endScale);
[s,s];

// Example: Opacity fades from 0 to 100 between seconds 1 and 3 using linear
linear(time, 1, 3, 0, 100);

// Example: Layer Opacity is 100% after 2 seconds, otherwise 0%
var timeThreshold = 2; // Seconds
if (time > timeThreshold) {
  100; // Opacity if condition is true
} else {
  0;   // Opacity if condition is false
}

// --- Inertial Bounce Controls ---
var amp = .055;     // Amplitude: How much bounce (e.g., 0.01 for subtle, 0.2 for more)
var freq = 1.8;     // Frequency: Bounces per second (e.g., 1 to 5)
var decayRate = 5.2;// Decay: How quickly bounce fades (e.g., 3 for slower, 10 for faster)

// --- Inertial Bounce Script (do not edit below unless you know what you're doing) ---
var n = 0;
if (numKeys > 0){
    n = nearestKey(time).index;
    if (key(n).time > time) n--;
}
var t = (n > 0) ? time - key(n).time : 0;
if (n > 0 && t >= 0){
    var v = velocityAtTime(key(n).time - thisComp.frameDuration/10);
    value + v * amp * Math.sin(freq * t * 2 * Math.PI) / Math.exp(decayRate * t);
} else {
    value;
}

// --- Orbit Controls ---
var centerLayerName = "CenterLayer"; // Name of the layer to orbit around
var orbitRadius = 500;             // Radius of the orbit in pixels
var orbitSpeed = 2;                // Speed of orbit (higher is faster, negative reverses)

// --- Orbit Script ---
var centerPt = thisComp.layer(centerLayerName).transform.position;
var currentAngle = time * orbitSpeed;
var x = centerPt[0] + Math.cos(currentAngle) * orbitRadius;
var y = centerPt[1] + Math.sin(currentAngle) * orbitRadius;

if (centerPt.length > 2 && transform.position.length > 2) { // If both are 3D
    var z = value[2]; // Maintain this layer's Z, or use centerPt[2] to orbit in center's Z plane
    [x, y, z];
} else { // For 2D layers
    [x, y];
}

// --- Bounce Controls ---
var horizontalSpeed = 300; // Speed in X direction (pixels per second)
var verticalSpeed = 200;   // Speed in Y direction (pixels per second)

// --- Bounce Script ---
var layerRect = sourceRectAtTime(time, false);
var effectiveLayerWidth = layerRect.width * transform.scale[0]/100;
var effectiveLayerHeight = layerRect.height * transform.scale[1]/100;
var compW = thisComp.width;
var compH = thisComp.height;
var minX = effectiveLayerWidth / 2;
var maxX = compW - (effectiveLayerWidth / 2);
var minY = effectiveLayerHeight / 2;
var maxY = compH - (effectiveLayerHeight / 2);
var t = time - inPoint;
var rawX = minX + (t * horizontalSpeed);
var rawY = minY + (t * verticalSpeed);
var bounceCountX = Math.floor(rawX / (maxX - minX));
var bounceCountY = Math.floor(rawY / (maxY - minY));
var finalX, finalY;

if (bounceCountX % 2 == 1){ finalX = maxX - (rawX % (maxX - minX)); }
else { finalX = minX + (rawX % (maxX - minX)); }
if (bounceCountY % 2 == 1){ finalY = maxY - (rawY % (maxY - minY)); }
else { finalY = minY + (rawY % (maxY - minY)); }
[finalX, finalY];

// --- Spring Controls ---
var leaderLayerName = "leader"; // Name of the layer to follow
var restLength = 20;          // Desired resting distance between leader and follower anchor points
var springStiffness = 0.1;    // Stiffness of the spring (e.g., 0.05 for softer, 0.2 for stiffer)
var dampingFactor = 0.95;     // Damping (0 to 1). Lower is more springy, higher is less oscillation.

// --- Spring Script ---
var leader = thisComp.layer(leaderLayerName);
var fDur = thisComp.frameDuration;
var currTime = time;
var pFollower = position.valueAtTime(0); // Follower's initial position (at its inPoint)
var vFollower = [0,0,0]; // Follower's initial velocity
if (position.length === 2) vFollower = [0,0]; // Match 2D/3D for velocity array

for (var t = 0; t <= currTime - thisLayer.inPoint; t += fDur){ // Iterate for duration layer has been active
    var leaderTime = thisLayer.inPoint + t; // Time to sample leader
    if (leaderTime > leader.outPoint) leaderTime = leader.outPoint; // Clamp if leader ends
    if (leaderTime < leader.inPoint) leaderTime = leader.inPoint;   // Clamp if leader starts later

    var pLeader = leader.transform.position.valueAtTime(leaderTime);
    var delta = pFollower - pLeader;
    var currentDist = length(delta);
    var springForceMagnitude = (currentDist - restLength) * springStiffness; // Hooke's Law
    
    var springForceVector = [0,0,0];
    if (currentDist > 0.001) { // Avoid division by zero if coincident
      springForceVector = normalize(delta) * springForceMagnitude;
    }
    if (position.length === 2 && springForceVector.length === 3) { // Ensure vector matches dimension
        springForceVector = [springForceVector[0], springForceVector[1]];
    }
    
    vFollower = (vFollower - springForceVector) * dampingFactor; // Apply force to velocity, then damp
    pFollower += vFollower * fDur; // Update follower's position (integrate velocity)
}
pFollower;

// --- Loopable Wiggle Controls ---
var wiggleFrequency = 1;    // Wiggles per second
var wiggleAmplitude = 110;  // Wiggle amount in pixels
var loopDurationSeconds = 3;// Duration of the loop in seconds

// --- Loopable Wiggle Script ---
var t = time % loopDurationSeconds;
var wiggle1 = wiggle(wiggleFrequency, wiggleAmplitude, 1, 0.5, t);
var wiggle2 = wiggle(wiggleFrequency, wiggleAmplitude, 1, 0.5, t - loopDurationSeconds);
linear(t, 0, loopDurationSeconds, wiggle1, wiggle2);

// --- Referencing Layers ---
// Option 1: By Layer Index (1 is top layer, 2 is second, etc.)
var layerA = thisComp.layer(1); 
var layerB = thisComp.layer(2);

// Option 2: By Layer Name (uncomment and use instead if preferred)
// var layerA = thisComp.layer("NameOfFirstLayer");
// var layerB = thisComp.layer("NameOfSecondLayer");

// --- Calculation ---
(layerA.transform.position + layerB.transform.position) / 2;

// --- Global Physics Settings (Reads from Null Layer "PhysicsSettings2D") ---
var settingsNullName = "PhysicsSettings2D";
var gravY = 980, wallBounce = 0.7, damping = 0.995; // Defaults
var minXWall = 0, maxXWall = thisComp.width, minYWall = 0, maxYWall = thisComp.height; // Defaults

try {
    var settingsLayer = thisComp.layer(settingsNullName);
    gravY = settingsLayer.effect("Gravity Y")("Slider");
    wallBounce = settingsLayer.effect("Wall Bounce Factor")("Slider");
    damping = settingsLayer.effect("Global Damping")("Slider");
    minXWall = settingsLayer.effect("Min X Wall")("Slider");
    maxXWall = settingsLayer.effect("Max X Wall")("Slider");
    minYWall = settingsLayer.effect("Min Y Wall")("Slider");
    maxYWall = settingsLayer.effect("Max Y Wall")("Slider");
} catch(err) { /* Use defaults if settings layer or sliders are missing */ }

// --- Individual Object Properties (Reads from sliders on THIS layer) ---
var iVelX = 0, iVelY = 0, radiusThis = 25; // Default radius
try { iVelX = effect("Initial Velocity X")("Slider"); } catch(e){ iVelX = (index % 7 - 3) * 20; } // Default variation
try { iVelY = effect("Initial Velocity Y")("Slider"); } catch(e){ iVelY = -(index % 5) * 50 -50; } // Default variation
try { radiusThis = Math.max(1, effect("Radius")("Slider")); } catch(e){} // Ensure radius is at least 1

// --- Simulation ---
var dt = thisComp.frameDuration;
var p = transform.position.valueAtTime(inPoint); // Start at initial keyframed position or value
var v = [iVelX, iVelY]; // Initial velocity

// Effective boundaries considering object radius
var effectiveMinX = minXWall + radiusThis;
var effectiveMaxX = maxXWall - radiusThis;
var effectiveMinY = minYWall + radiusThis;
var effectiveMaxY = maxYWall - radiusThis;

// Iterate from layer's inPoint up to the current time to simulate physics progression
for (var t = inPoint; t < time; t += dt){
    // Apply Gravity (only to Y velocity)
    v[1] = v[1] + gravY * dt;

    // Apply Global Damping (Air Resistance)
    v = v * damping;       

    // Update Position based on velocity
    p = p + v * dt;

    // Boundary Collisions & Bounce
    // X-axis
    if (p[0] < effectiveMinX) { 
        p[0] = effectiveMinX; 
        v[0] *= -wallBounce; 
    } else if (p[0] > effectiveMaxX) { 
        p[0] = effectiveMaxX; 
        v[0] *= -wallBounce; 
    }
    // Y-axis
    if (p[1] < effectiveMinY) { 
        p[1] = effectiveMinY; 
        v[1] *= -wallBounce; 
    } else if (p[1] > effectiveMaxY) { 
        p[1] = effectiveMaxY; 
        v[1] *= -wallBounce; 
    }
}
p; // Resulting position for the current frame

// --- LookAt Controls ---
var targetLayerName = "targetLayer"; // Name of the layer to point towards
var artworkPointingOffsetDegrees = 0; // Adjust if your artwork points up (e.g., 90 or -90), left (e.g., 180) by default

// --- LookAt Script ---
function calculateLookAtAngle(fromPoint, toPoint) {
    var deltaX = toPoint[0] - fromPoint[0];
    var deltaY = toPoint[1] - fromPoint[1];
    var angleRad = Math.atan2(deltaY, deltaX);
    return radiansToDegrees(angleRad);
}
var thisLayerPosition = transform.position;
var targetPosition = thisComp.layer(targetLayerName).transform.position;
calculateLookAtAngle(thisLayerPosition, targetPosition) + artworkPointingOffsetDegrees;

// --- 3D LookAt Controls ---
var targetLayerName = "Target";         // Name of the layer to look AT
var viewPointLayerName = "Point";       // Name of layer defining the viewpoint. 
                                        // If this layer IS the viewpoint, use thisLayer.name or an empty string.

// --- 3D LookAt Script ---
var targetObj = thisComp.layer(targetLayerName);
var fromPosition;

if (viewPointLayerName == "" || thisComp.layer(viewPointLayerName) == thisLayer) {
    fromPosition = toWorld(transform.anchorPoint); // This layer is the viewpoint
} else {
    var viewPointObj = thisComp.layer(viewPointLayerName);
    fromPosition = viewPointObj.toWorld(viewPointObj.transform.anchorPoint);
}
var targetPosition = targetObj.toWorld(targetObj.transform.anchorPoint);
lookAt(fromPosition, targetPosition);

// --- Ignore Parent Rotation Script ---
if (hasParent) {
  value - parent.transform.rotation;
} else {
  value; // No parent, so just use its own rotation
}

// --- Pendulum Controls ---
var swingFrequency = 1.0;   // Swings per second (e.g., 1 full back-and-forth per second)
var initialAmplitude = 45;  // Initial swing angle in degrees (e.g., 45 degrees to each side)
var decayRate = 0.5;        // How quickly swing dampens (0 = no decay, higher = faster stop)

// --- Pendulum Script ---
initialAmplitude * Math.sin(time * swingFrequency * Math.PI * 2) * Math.exp(-decayRate * time);

// --- Maintain Scale Script ---
var newScale = [];
if (hasParent) {
  var parentScale = parent.transform.scale.value;
  for (var i = 0; i < parentScale.length; i++){ // Works for 2D or 3D scale
    if (parentScale[i] === 0) { // Avoid division by zero
        newScale[i] = value[i]; // Or some large number if you want it to "disappear"
    } else {
        newScale[i] = value[i] * 100 / parentScale[i];
    }
  }
} else {
  newScale = value; // No parent, so use its own scale value
}
newScale;

// --- Pulse Controls ---
var pulseSpeed  = 1.0;      // Cycles per second (e.g., 1.0 for one full pulse per second)
var pulseAmount = 20;       // Percentage of scale change (e.g., 20 means ±20% if mode is 0)
var baseScaleValue = [100, 100]; // Resting scale [X,Y] or [X,Y,Z] for 3D layers
var phaseOffsetCycles = 0.0;// Shifts start point of pulse (0 to 1, e.g., 0.25 starts at peak)
var pulseMode = 1;          // 0 = grow & shrink; 1 = only grow from base; 2 = only shrink from base

// --- Pulse Script ---
var angle = (time * pulseSpeed + phaseOffsetCycles) * 2 * Math.PI;
var rawOffset;
if (pulseMode == 0) { rawOffset = Math.sin(angle) * pulseAmount; }
else if (pulseMode == 1) { rawOffset = ((1 - Math.cos(angle)) / 2) * pulseAmount; }
else if (pulseMode == 2) { rawOffset = -((1 - Math.cos(angle)) / 2) * pulseAmount; }
else { rawOffset = Math.sin(angle) * pulseAmount; } // Fallback
var finalScale = [];
for (var i = 0; i < baseScaleValue.length; i++) {
    finalScale[i] = baseScaleValue[i] + rawOffset;
}
finalScale;

// --- Fade Controls ---
var startFadeDistance = 500; // Distance (pixels) from camera where fade begins (100% opacity closer than this)
var endFadeDistance = 1500;  // Distance (pixels) from camera where layer is fully faded (0% opacity further than this)
 
// --- Fade Script ---
var camPosition;
try { 
    camPosition = thisComp.activeCamera.toWorld([0,0,0]);  
} catch (err) {  
    var compWidthForDefaultCam = thisComp.width * thisComp.pixelAspect;  
    var defaultCamZ = (compWidthForDefaultCam/2) / Math.tan(degreesToRadians(19.799)); // Approx 50mm lens
    camPosition = [thisComp.width/2, thisComp.height/2, -defaultCamZ];  
}  
var layerPosition = toWorld(anchorPoint);  
var distanceToCam = length(camPosition, layerPosition);  
linear(distanceToCam, startFadeDistance, endFadeDistance, 100, 0);

// --- Maintain Apparent Stroke Width Script ---
// No user-editable variables needed for this typical implementation.
// It divides the original stroke 'value' by a measure of the layer's current scale.
var scaleFactor = length(toComp([0,0]), toComp([0.7071,0.7071]));
if (scaleFactor === 0) scaleFactor = 0.001; // Avoid division by zero
value / scaleFactor;

// Example: Changing Font, Size, and Fill Color
text.sourceText.style
   .setFont("Impact")
   .setFontSize(120)
   .setFillColor([1, 0.5, 0]); // Orange: [Red, Green, Blue] values 0-1

// Example: Adding a Stroke and Changing Text Content
var styleObj = text.sourceText.style;
styleObj = styleObj.setStrokeColor([0.2, 0.8, 0.2]); // Green stroke
styleObj = styleObj.setStrokeWidth(5);
styleObj = styleObj.setApplyStroke(true); // Important to make stroke visible
styleObj = styleObj.setTracking(20);
styleObj.setText("Styled with Expressions!"); // This must be the last style modification if changing text content

// --- Targeting Controls ---
// Example: Affect only the first 3 characters (indices 0, 1, 2)
var charactersToTarget = 3;
if (textIndex < charactersToTarget) { 
    100; // Full effect
} else { 
    0;   // No effect
}

// Example: Affect characters from index 2 up to (but not including) index 5
var startIndex = 2; // Third character
var endIndex = 5;   // Affects up to character before this index (i.e., characters at index 2, 3, 4)

if (textIndex >= startIndex && textIndex < endIndex) { 
    100; // Apply full animator effect
} else { 
    0;   // No effect for other characters
}

// --- Nth Character Selector Controls ---
// Apply this to a Text Animator's Expression Selector > Amount property.
var nthValue = 2; // Select every 2nd character (for every other character)
                  // Change to 3 for every 3rd character, etc.
var startOffset = 0; // 0 to start with the Nth character (e.g. if Nth=2, characters 1,3,5... using 0-based textIndex)
                     // 1 to start with the (Nth + offset) character (e.g. if Nth=2 & offset=1, characters 0,2,4...)

// --- Nth Character Script ---
if (nthValue <= 0) nthValue = 1; // Prevent division by zero or negative values

if ((textIndex + startOffset) % nthValue == 0) {
    100; // Apply full animator effect to this character
} else {
    0;   // No effect for other characters
}

// --- Dynamic Text Scaling Controls ---
var maxWidthBoundary = 500; // Desired maximum width for the text
var maxHeightBoundary = 100; // Desired maximum height for the text
var overallScalePercentage = 100; // Additional overall scale (100 = no change from fit)
var measureAtCurrentTime = true; // true: measure text at current time; false: measure at time 0

// --- Scaling Script ---
var timeToMeasureAt = measureAtCurrentTime ? time : 0;
var textRect = sourceRectAtTime(timeToMeasureAt);
var currentTextWidth = textRect.width;
var currentTextHeight = textRect.height;
var widthScaleFactor = 1; 
var heightScaleFactor = 1;

if (currentTextWidth > 0) widthScaleFactor = maxWidthBoundary / currentTextWidth;
if (currentTextHeight > 0) heightScaleFactor = maxHeightBoundary / currentTextHeight;

var finalFitScaleFactor = Math.min(widthScaleFactor, heightScaleFactor);
var s = finalFitScaleFactor * overallScalePercentage;

if (currentTextWidth === 0 || currentTextHeight === 0) { s = overallScalePercentage; }
else if (finalFitScaleFactor >= 1 && overallScalePercentage < 100) { s = overallScalePercentage; }
else if (finalFitScaleFactor < 1) { s = finalFitScaleFactor * 100 * (overallScalePercentage / 100); }
else { s = overallScalePercentage; }
[s, s];

// --- Anchor Point Control ---
// Choose a number from 1 to 9 for anchorPosition:
// 1=Top Left,    2=Top Center,    3=Top Right
// 4=Middle Left, 5=Middle Center, 6=Middle Right
// 7=Bottom Left, 8=Bottom Center, 9=Bottom Right
var anchorPosition = 5; 
var measureAtCurrentTime = true; 

// --- Anchor Point Script ---
var timeToMeasureAt = measureAtCurrentTime ? time : 0;
var layerRect = thisLayer.sourceRectAtTime(timeToMeasureAt); 
var L = layerRect.left;
var T = layerRect.top;
var W = layerRect.width;
var H = layerRect.height;
var xAnchor, yAnchor;

switch(anchorPosition){
    case 1: xAnchor=L; yAnchor=T; break;
    case 2: xAnchor=L+W/2; yAnchor=T; break;
    case 3: xAnchor=L+W; yAnchor=T; break;
    case 4: xAnchor=L; yAnchor=T+H/2; break;
    case 5: xAnchor=L+W/2; yAnchor=T+H/2; break;
    case 6: xAnchor=L+W; yAnchor=T+H/2; break;
    case 7: xAnchor=L; yAnchor=T+H; break;
    case 8: xAnchor=L+W/2; yAnchor=T+H; break;
    case 9: xAnchor=L+W; yAnchor=T+H; break;
    default: xAnchor=L+W/2; yAnchor=T+H/2;
}
[xAnchor, yAnchor];

// --- Timer Control ---
// Add a "Slider Control" effect to this text layer.
// The slider's value will be interpreted as total seconds.
var totalSecondsInput = Math.round(effect("Slider Control")("Slider").value);

// --- Timer Script ---
var hrs = Math.floor(totalSecondsInput / 3600);
var mins = Math.floor((totalSecondsInput % 3600) / 60);
var secs = totalSecondsInput % 60;

function addLeadingZero(n) {
  return n < 10 ? "0" + n : "" + n;
}
addLeadingZero(hrs) + ":" + addLeadingZero(mins) + ":" + addLeadingZero(secs);

// --- Source Layer ---
// Change "SourceTextLayerName" to the actual name of your source text layer.
var sourceLayer = thisComp.layer("SourceTextLayerName"); 

// --- Copy Script ---
var sourceStyle = sourceLayer.text.sourceText.getStyleAt(0, time); // Gets style from 1st char of source at current time
sourceStyle.setText(sourceLayer.text.sourceText.value); // Applies source style and text content