After Effects Expression Reference Expressions Guide
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After Effects Expression Reference Release 0.0.3 Jun 11, 2018 Introduction 1 Introduction 3 2 Resources 5 3 Examples 3.1 Get this project’s AEP name (AE 15.1+ only) . . . . . . . 3.2 Make a layer revolve in a circle . . . . . . . . . . . . . . 3.3 Rotate the hands of a clock . . . . . . . . . . . . . . . . . 3.4 Position one layer between two others . . . . . . . . . . . 3.5 Create a trail of images . . . . . . . . . . . . . . . . . . . 3.6 Create a bulge between two layers . . . . . . . . . . . . . 3.7 Fade opacity of a 3D layer based on distance from camera 3.8 Make a 3D layer invisible if facing away from camera . . 3.9 Flip layer horizontally if facing away from camera . . . . 3.10 Animate scale at each layer marker . . . . . . . . . . . . 3.11 Start or stop wiggle at specific time . . . . . . . . . . . . 3.12 Match camera focal plane to another layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7 7 8 8 9 9 10 10 10 10 11 12 Global 4.1 comp(name) . . . . . . . . . . . . . . 4.2 footage(name) . . . . . . . . . . . . . 4.3 thisProject . . . . . . . . . . . . . . . 4.4 thisComp . . . . . . . . . . . . . . . . 4.5 thisLayer . . . . . . . . . . . . . . . . 4.6 thisProperty . . . . . . . . . . . . . . . 4.7 time . . . . . . . . . . . . . . . . . . . 4.8 colorDepth . . . . . . . . . . . . . . . 4.9 posterizeTime(framesPerSecond) . 4.10 value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 13 13 14 14 14 14 15 15 15 15 4 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Time conversion 5.1 framesToTime(frames, fps=1.0 / thisComp.frameDuration) 5.2 timeToTimecode(t=time + thisComp.displayStartTime, isDuration=false) . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 timeToNTSCTimecode(t=time + thisComp.displayStartTime, ntscDropFrame=false, isDuration=false) . . . . . . . . . . . . . . . . . . . . . . . . . timecodeBase=30, . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 18 18 18 i 5.4 5.5 6 timeToFeetAndFrames(t=time + thisComp.displayStartTime, fps=1.0 / thisComp.frameDuration, framesPerFoot=16, isDuration=false) . . . . . . . . . timeToCurrentFormat(t=time + thisComp.displayStartTime, fps=1.0 / thisComp.frameDuration, isDuration=false) . . . . . . . . . . . . . . . . . . . . . . . 19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 21 22 22 22 23 23 23 24 24 24 25 Random Numbers 7.1 seedRandom(offset, timeless=false) . . . . . . 7.2 random() . . . . . . . . . . . . . . . . . . . . . . . . . 7.3 random(maxValOrArray) . . . . . . . . . . . . . . . 7.4 random(minValOrArray, maxValOrArray) . . . . 7.5 gaussRandom() . . . . . . . . . . . . . . . . . . . . . . 7.6 gaussRandom(maxValOrArray) . . . . . . . . . . . 7.7 gaussRandom(minValOrArray, maxValOrArray) 7.8 noise(valOrArray) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 27 28 28 28 29 29 29 30 Interpolation 8.1 linear(t, tMin, tMax, value1, value2) . . 8.2 linear(t, value1, value2) . . . . . . . . . 8.3 ease(t, value1, value2) . . . . . . . . . . 8.4 ease(t, tMin, tMax, value1, value2) . . 8.5 easeIn(t, value1, value2) . . . . . . . . . 8.6 easeIn(t, tMin, tMax, value1, value2) . 8.7 easeOut(t, value1, value2) . . . . . . . . 8.8 easeOut(t, tMin, tMax, value1, value2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 31 32 32 33 33 33 34 34 Color Conversion 9.1 rgbToHsl(rgbaArray) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.2 hslToRgb(hslaArray) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 35 35 10 Other Math 10.1 degreesToRadians(degrees) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2 radiansToDegrees(radians) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 37 37 11 Project 11.1 Project.fullPath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Project.bitsPerChannel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3 Project.linearBlending . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 39 39 40 12 Comp 12.1 Comp.layer(index) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.2 Comp.layer(name) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.3 Comp.layer(otherLayer, relIndex) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 41 41 42 7 8 9 ii Vector Math 6.1 add(vec1, vec2) . . . . . . . . . 6.2 sub(vec1, vec2) . . . . . . . . . 6.3 mul(vec, amount) . . . . . . . . 6.4 div(vec, amount) . . . . . . . . . 6.5 clamp(value, limit1, limit2) 6.6 dot(vec1, vec2) . . . . . . . . . 6.7 cross(vec1, vec2) . . . . . . . . 6.8 normalize(vec) . . . . . . . . . . 6.9 length(vec) . . . . . . . . . . . . 6.10 length(point1, point2) . . . . . 6.11 lookAt(fromPoint, atPoint) . 19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.4 12.5 12.6 12.7 12.8 12.9 12.10 12.11 12.12 12.13 12.14 12.15 12.16 12.17 12.18 12.19 12.20 12.21 Comp.marker . . . . . . . . Comp.marker.key(index) . Comp.marker.key(name) . Comp.marker.nearestKey(t) Comp.marker.numKeys . . Comp.numLayers . . . . . Comp.activeCamera . . . . Comp.width . . . . . . . . Comp.height . . . . . . . . Comp.duration . . . . . . . Comp.ntscDropFrame . . . Comp.displayStartTime . . Comp.frameDuration . . . . Comp.shutterAngle . . . . . Comp.shutterPhase . . . . . Comp.bgColor . . . . . . . Comp.pixelAspect . . . . . Comp.name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 42 43 43 44 44 44 44 45 45 45 45 46 46 46 46 46 47 13 Footage 13.1 Footage.width . . . . . 13.2 Footage.height . . . . . 13.3 Footage.duration . . . . 13.4 Footage.frameDuration . 13.5 Footage.ntscDropFrame 13.6 Footage.pixelAspect . . 13.7 Footage.name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 49 49 50 50 50 50 50 14 Camera 14.1 Camera.pointOfInterest 14.2 Camera.zoom . . . . . . 14.3 Camera.depthOfField . 14.4 Camera.focusDistance . 14.5 Camera.aperture . . . . 14.6 Camera.blurLevel . . . 14.7 Camera.active . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 51 52 52 52 52 53 53 15 Light 15.1 Light.pointOfInterest . 15.2 Light.intensity . . . . 15.3 Light.color . . . . . . 15.4 Light.coneAngle . . . 15.5 Light.coneFeather . . 15.6 Light.shadowDarkness 15.7 Light.shadowDiffusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 55 56 56 56 56 57 57 16 Effect 16.1 Effect.active . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16.2 Effect.param(name) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16.3 Effect.param(index) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 59 59 60 17 Mask 17.1 Mask.maskOpacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17.2 Mask.maskFeather . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17.3 Mask.maskExpansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 61 61 62 . . . . . . . iii 17.4 Mask.invert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Property 18.1 value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.2 valueAtTime(t) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.3 velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.4 velocityAtTime(t) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.5 speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.6 speedAtTime(t) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.7 wiggle(freq, amp, octaves=1, amp_mult=0.5, t=time) . . . . . 18.8 temporalWiggle(freq, amp, octaves=1, amp_mult=0.5, t=time) 18.9 smooth(width=.2, samples=5, t=time) . . . . . . . . . . . . . . 18.10 loopIn(type="cycle", numKeyframes=0) . . . . . . . . . . . . . 18.11 loopOut(type="cycle", numKeyframes=0) . . . . . . . . . . . . 18.12 loopInDuration(type="cycle", duration=0) . . . . . . . . . . . . 18.13 loopOutDuration(type="cycle", duration=0) . . . . . . . . . . . 18.14 key(index) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.15 key(markerName) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.16 nearestKey(t) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.17 numKeys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.18 propertyGroup(countUp=1) . . . . . . . . . . . . . . . . . . . . . . . 18.19 propertyIndex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.20 name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 63 63 64 64 65 65 65 66 67 67 68 68 69 69 69 70 70 70 71 71 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [0,100]], . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 74 74 74 75 75 75 76 76 . . . . . . 77 20 Key 20.1 Key.value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20.2 Key.time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20.3 Key.index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 79 79 80 21 MarkerKey 21.1 Marker.duration . . . 21.2 Marker.comment . . . 21.3 Marker.chapter . . . . 21.4 Marker.url . . . . . . 21.5 Marker.frameTarget . 21.6 Marker.eventCuePoint 21.7 Marker.cuePointName 21.8 Marker.parameters . . . . . . . . . . 81 82 82 82 82 83 83 83 83 22 Layer Sub-objects 22.1 Layer.source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22.2 Layer.sourceTime(t=time) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22.3 Layer.sourceRectAtTime(t = time, includeExtents = false) . . . . . . . . . . . . . . 85 85 85 86 . . . . . . . . . . . . . . . . . . . . 19 Path Property 19.1 name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19.2 pathProperty.points(t=time) . . . . . . . . . . . . . . . . . . . . . . . . 19.3 pathProperty.inTangents(t=time) . . . . . . . . . . . . . . . . . . . . . 19.4 pathProperty.outTangents(t=time) . . . . . . . . . . . . . . . . . . . . . 19.5 pathProperty.isClosed() . . . . . . . . . . . . . . . . . . . . . . . . . . . 19.6 pathProperty.pointOnPath(percentage=0.5, t=time) . . . . . . . . . 19.7 pathProperty.tangentOnPath(percentage=0.5, t=time) . . . . . . . 19.8 pathProperty.normalOnPath(percentage=0.5, t=time) . . . . . . . . 19.9 pathProperty.createPath(points=[[0,0], [100,0], [100,100], inTangents=[], outTangents=[], is_closed=true) . . . . . iv . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22.4 22.5 22.6 22.7 Layer.effect(name) . Layer.effect(index) Layer.mask(name) . Layer.mask(index) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 87 87 88 23 Layer General 23.1 Layer.width . . . . . . . . . . . . . . . . . . . 23.2 Layer.height . . . . . . . . . . . . . . . . . . 23.3 Layer.index . . . . . . . . . . . . . . . . . . . 23.4 Layer.parent . . . . . . . . . . . . . . . . . . 23.5 Layer.hasParent . . . . . . . . . . . . . . . . 23.6 Layer.inPoint . . . . . . . . . . . . . . . . . . 23.7 Layer.outPoint . . . . . . . . . . . . . . . . . 23.8 Layer.startTime . . . . . . . . . . . . . . . . . 23.9 Layer.hasVideo . . . . . . . . . . . . . . . . . 23.10 Layer.hasAudio . . . . . . . . . . . . . . . . . 23.11 Layer.active . . . . . . . . . . . . . . . . . . . 23.12 Layer.enabled . . . . . . . . . . . . . . . . . . 23.13 Layer.audioActive . . . . . . . . . . . . . . . 23.14 Layer.sampleImage(point, radius=[0.5, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5], postEffect=true, t=time) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 89 89 89 90 90 90 91 91 91 91 92 92 92 92 24 Layer Properties 24.1 Layer.anchorPoint . . . . . 24.2 Layer.position . . . . . . . 24.3 Layer.scale . . . . . . . . . 24.4 Layer.rotation . . . . . . . . 24.5 Layer.opacity . . . . . . . . 24.6 Layer.audioLevels . . . . . 24.7 Layer.timeRemap . . . . . . 24.8 Layer.marker.key(index) . 24.9 Layer.marker.key(name) . . 24.10 Layer.marker.nearestKey(t) 24.11 Layer.marker.numKeys . . . 24.12 Layer.name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 95 95 96 96 96 96 97 97 97 98 98 98 25 Layer Space Transforms 25.1 toComp(point, t=time) . . . . . . . 25.2 fromComp(point, t=time) . . . . . . 25.3 toWorld(point, t=time) . . . . . . . 25.4 fromWorld(point, t=time) . . . . . . 25.5 toCompVec(vec, t=time) . . . . . . . . 25.6 fromCompVec(vec, t=time) . . . . . . 25.7 toWorldVec(vec, t=time) . . . . . . . . 25.8 fromWorldVec(vec, t=time) . . . . . 25.9 fromCompToSurface(point, t=time) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 99 100 100 101 101 101 102 102 103 26 Layer 3D 26.1 Layer.orientation . . . . 26.2 Layer.rotationX . . . . . 26.3 Layer.rotationY . . . . . 26.4 Layer.rotationZ . . . . . 26.5 Layer.lightTransmission 26.6 Layer.castsShadows . . 26.7 Layer.acceptsShadows . 26.8 Layer.acceptsLights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 105 105 105 106 106 106 106 106 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v 26.9 26.10 26.11 26.12 26.13 vi Layer.ambient Layer.diffuse . Layer.specular Layer.shininess Layer.metal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 107 107 107 107 After Effects Expression Reference, Release 0.0.3 The reference is still being edited and improved upon. Introduction 1 After Effects Expression Reference, Release 0.0.3 2 Introduction CHAPTER 1 Introduction Use the After Effects expression elements along with standard JavaScript elements to write your expressions. You can use the Expression Language menu at any time to insert methods and attributes into an expression, and you can use the pick whip at any time to insert properties. If an argument description contains an equal sign (=) and a value (such as t=time or width=.2), then the argument uses the included default value if you don’t specify a different value. Some argument descriptions include a number in square brackets—this number indicates the dimension of the expected property or Array. Some return-value descriptions include a number in square brackets—this number specifies the dimension of the returned property or Array. If a specific dimension is not included, the dimension of the returned Array depends on the dimension of the input. The W3Schools JavaScript reference website provides information for the standard JavaScript language, including pages for the JavaScript Math and String objects. 3 After Effects Expression Reference, Release 0.0.3 4 Chapter 1. Introduction CHAPTER 2 Resources The user ‘Beaver’ posted 5 Expressions that will change your life on the Mograph forums. Dan Ebberts provides example expressions and tutorials for learning how to work with expressions on his MotionScript website. For example, Dan provides an excellent page about collision detection. Colin Braley provides a tutorial and example project on his website that show how to use expressions to make one layer repel others in a natural-seeming manner. The AE Enhancers forum provides many examples and much useful information about expressions, as well as scripts and animation presets. In this post on the AE Enhancers forum, Paul Tuersley provides a tutorial and example project that show how to use expressions to animate several layers in a swarm. Rick Gerard provides an example on his website that demonstrates rolling a square object along a floor so that the sides stay in contact with the floor plane. Carl Larsen provides a video tutorial on the Creative COW website that demonstrates how to use expressions and parenting to relate the rotation of a set of wheels to the horizontal movement of a vehicle. Chris Zwar provides an example project on his website for automatically arranging still images or videos into a grid (like a video wall). You can easily adjust position and spacing with sliders that are connected to a system of expressions. There are three compositions in the project—one for stills, one for videos, and one to create an autostoryboard in which a video is sampled at user-defined intervals and aligned into a grid. JJ Gifford’s website provides several example projects that demonstrate how to use expressions. Maltaannon (Jerzy Drozda, Jr.) provides a video tutorial on his website that shows how to use expressions to create a volume meter using the results of the Convert Audio To Keyframes command. 5 After Effects Expression Reference, Release 0.0.3 6 Chapter 2. Resources CHAPTER 3 Examples Note: Many of the examples in this section are based on expressions provided by Dan Ebberts. 3.1 Get this project’s AEP name (AE 15.1+ only) While there is no method to directly access your AEP’s name, you CAN get the full path to the AEP. With some string manipulation, you can derive the aep name from this: var aepName = thisProject.fullPath.split($.os.indexOf("Windows") > -1 ? "\\" : "/"). ˓→pop(); If you wanted to write “Unsaved” in that case, you can use the following expression: var aepName = thisProject.fullPath.split($.os.indexOf("Windows") > -1 ? "\\" : "/"). ˓→pop(); aepName = aepName === "" ? "Unsaved" : aepName; 3.2 Make a layer revolve in a circle You can create an expression without using properties from other layers. For example, you can make a layer revolve in a perfect circle. 1. Select a layer, press P to reveal its Position property in the Timeline panel, and Alt-click (Windows) or Optionclick (Mac OS) the stopwatch to the left of the property name. 2. Enter the following in the expression field: 7 After Effects Expression Reference, Release 0.0.3 [(thisComp.width/2), (thisComp.height/2)] + [Math.sin(time)*50, -Math. ˓→cos(time)*50] 3.3 Rotate the hands of a clock You can use the pick whip to link rotation values between layers to animate the hands on a clock—as the hour hand moves from hour to hour, the minute hand rotates the full circumference of the clock face. This type of animation would take a long time to create if you had to set each keyframe for both hand layers, but with the pick whip, you can do it in a matter of minutes. 1. Import or create two long, narrow solid-color layers: an hour hand and a minute hand. 2. Set the anchor points at the ends of the layers. 3. Move the layers so that the anchor points are at the center of the composition. 4. Set Rotation keyframes for the hour hand. 5. Select the Rotation property for the minute hand and choose Animation > Add Expression. 6. Drag the pick whip to the Rotation property for the hour hand. The following expression appears: thisComp.layer("hour hand").rotation 7. To make the minute hand rotate 12 times as fast as the hour hand, add * 12 at the end of the expression as follows: thisComp.layer("hour hand").rotation * 12 3.4 Position one layer between two others This example expression positions and maintains one layer at a balanced distance between two other layers. 1. Start with three layers. 2. Animate the positions of the first two layers in the Timeline panel. 3. Select the third layer, press P to reveal the Position property, and Alt-click (Windows) or Option-click (Mac OS) the stopwatch button to the left of the property name. 4. Enter the following in the expression field: (thisComp.layer(1).position + thisComp.layer(2).position)/2 8 Chapter 3. Examples After Effects Expression Reference, Release 0.0.3 3.5 Create a trail of images This example expression instructs a layer to be at the same position as the next higher layer in the Timeline panel, but delayed by a specified amount of time (in this case, 0.5 seconds). You can set similar expressions for the other geometric properties. 1. Start with two solid-color layers that are scaled to approximately 30% of the composition size. (See Solid-color layers and solid-color footage items.) 2. Animate the position of the first layer. 3. Select the second layer, press P to reveal the Position property, and Alt-click (Windows) or Option-click (Mac OS) the stopwatch button to the left of the property name. 4. Enter the following in the expression field: thisComp.layer(thisLayer, -1).position.valueAtTime(time - .5) 5. Duplicate the last layer five times by selecting it and pressing Ctrl+D (Windows) or Command+D (Mac OS) five times. All layers follow the same path, and each is delayed 0.5 seconds from the previous. Note: Dan Ebberts provides more examples and techniques for creating trails of images on his MotionScript website. 3.6 Create a bulge between two layers This example expression synchronizes the Bulge Center argument of the Bulge effect in one layer with the position of another layer. For example, you can create an effect that looks like a magnifying glass moving over a layer, with the contents under the magnifying glass bulging as the lens (that is, the overlying layer) moves. This expression uses the fromWorld method, which makes the expression work correctly regardless of whether you move the magnifying glass layer or the underlying layer. You can rotate or scale the underlying layer, and the expression stays intact. You can also use other effects, such as Ripple, with this expression. 1. Start with two layers. Make one layer a magnifying glass or similar object with a hole in the middle and name it Magnifier. (See Creating layers.) 2. Animate the position of the magnifying glass layer. (See Motion paths.) 3. Apply the Bulge effect to the other layer. (See Apply an effect or animation preset.) 4. Select the Bulge Center property of the Bulge effect in the Timeline panel and choose Animation > Add Expression, or Alt-click (Windows) or Option-click (Mac OS) the stopwatch button for the property. 5. Select the default expression text and type the following: fromWorld(thisComp.layer("Magnifier").position) 3.5. Create a trail of images 9 After Effects Expression Reference, Release 0.0.3 3.7 Fade opacity of a 3D layer based on distance from camera Apply the following expression to the Opacity property of a 3D layer: startFade = 500; // Start fade 500 pixels from camera. endFade = 1500; // End fade 1500 pixels from camera. try { // Check whether there's a camera C = thisComp.activeCamera.toWorld([0,0,0]); } catch (err) { // No camera, so assume 50mm w = thisComp.width * thisComp.pixelAspect; z = (w/2)/Math.tan(degreesToRadians(19.799)); C = [0,0,-z]; } P = toWorld(anchorPoint); d = length(C,P); linear(d,startFade,endFade,100,0) The fade starts at a distance of 500 pixels from the camera and is complete at 1500 pixels from the camera. The linear interpolation method is used to map distance values to opacity values. 3.8 Make a 3D layer invisible if facing away from camera Apply the following expression to the Opacity property of a 3D layer: if (toCompVec([0, 0, 1])[2] > 0 ) value else 0 Note: Dan Ebberts explains this expression on his MotionScript website. 3.9 Flip layer horizontally if facing away from camera Apply the following expression to the Scale property of a 3D layer: if (toCompVec([0, 0, 1])[2] > 0 ) value else [-value[0], value[1], value[2]] 3.10 Animate scale at each layer marker Apply the following expression to a Scale property to make a layer wobble at each marker: 10 Chapter 3. Examples After Effects Expression Reference, Release 0.0.3 n = 0; t = 0; if (marker.numKeys > 0){ n = marker.nearestKey(time).index; if (marker.key(n).time > time) n--; } if (n > 0) t = time - marker.key(n).time; amp = 15; freq = 5; decay = 3.0; angle = freq * 2 * Math.PI * t; scaleFact = (100 + amp * Math.sin(angle) / Math.exp(decay * t)) / 100; [value[0] * scaleFact, value[1] / scaleFact]; 3.11 Start or stop wiggle at specific time You can use any expression in place of the wiggle expression used here, to begin and end the influence of any expression at a specific time. Apply the following expression to a property to wiggle it beginning at time 2 seconds: timeToStart = 2; if (time > timeToStart) { wiggle(3,25); } else { value; } Apply the following expression to a property to stop wiggling it at time 4 seconds: timeToStop = 4; if (time > timeToStop) { value; } else { wiggle(3,25); } Apply the following expression to a property to start wiggling it at time 2 seconds and stop wiggling it at time 4 seconds: timeToStart = 2; timeToStop = 4; if ((time > timeToStart) && (time < timeToStop)) { wiggle(3,25); } else { value; } 3.11. Start or stop wiggle at specific time 11 After Effects Expression Reference, Release 0.0.3 3.12 Match camera focal plane to another layer Apply the following expression to the Focus Distance property of a camera layer to have its focus distance match the distance to the anchor point of a layer named “target”: target = thisComp.layer("target"); V1 = target.toWorld(target.anchorPoint) - toWorld([0,0,0]); V2 = toWorldVec([0,0,1]); dot(V1,V2); Note: Dan Ebberts explains this expression example in detail on his Motionscript website. 12 Chapter 3. Examples CHAPTER 4 Global 4.1 comp(name) Description Retrieves another composition by name. Parameters name String name String Type Comp 4.2 footage(name) Description Retrieves a footage item by name. Parameters Type Footage 13 After Effects Expression Reference, Release 0.0.3 4.3 thisProject Description Represents the project which contains the expression. Type Project 4.4 thisComp Description Represents the composition containing the expression. Type Comp 4.5 thisLayer Description Represents the layer containing the expression. Because thisLayer is the default object, its use is optional. For example, you can start an expression with thisLayer.width or width and get the same result. Type Layer, Light, or Camera 4.6 thisProperty Description Represents the property containing the expression. For example, if you write an expression on the Rotation property, you can start an expression with thisProperty to refer to the Rotation property. Type Property 14 Chapter 4. Global After Effects Expression Reference, Release 0.0.3 4.7 time Description Represents the composition time, in seconds, at which the expression is being evaluated. Type Number 4.8 colorDepth Description Type the project color depth value. For example, colorDepth returns 16 when the project color depth is 16 bits per channel. Type Number 4.9 posterizeTime(framesPerSecond) Description This expression allows you to set the frame rate for a property to be lower than the frame rate of the composition. For example, the following expression updates the property value with a random value once per second: posterizeTime(1); random() Parameters framesPerSecond Number The framesPerSecond value becomes the frame rate from which the rest of the expression operates. Type Number 4.10 value Description Represents the value at the current time for the property containing the expression. Type Number, Array, or String 4.7. time 15 After Effects Expression Reference, Release 0.0.3 16 Chapter 4. Global CHAPTER 5 Time conversion Note: If you want more control over the look of timecode in your footage, use the timeToCurrentFormat method or other timeTo methods to generate the timecode instead of using the Timecode or Numbers effect. Create a text layer, add an expression to the Source Text property, and enter timeToCurrentFormat() in the expression field. With this method, you can format and animate the timecode text. In addition, the timecode uses the same display style defined by the current project settings. timeToFrames(t=time + thisComp.displayStartTime, fps=1.0 / thisComp.frameDuration, isDuration=false) ***************************************************************************************** Desciption Converts the value of t, which defaults to the current composition time, to an integer number of frames. The number of frames per second is specified in the fps argument, which defaults to the frame rate of the current composition (1.0 / thisComp.frameDuration). The isDuration argument, which defaults to false, should be true if the t value represents a difference between two times instead of an absolute time. Absolute times are rounded down toward negative infinity; durations are rounded away from zero (up for positive values). Parameters t fps isDuration Number Number Boolean Type Number 17 After Effects Expression Reference, Release 0.0.3 5.1 framesToTime(frames, fps=1.0 / thisComp.frameDuration) Desciption The inverse of timeToFrames. Returns the time corresponding to the frames argument, which is required. It doesn’t have to be an integer. See timeToFrames for explanation of the fps argument. Parameters frames fps Number Number Type Number 5.2 timeToTimecode(t=time + thisComp.displayStartTime, timecodeBase=30, isDuration=false) Desciption Converts the value of t to a String representing timecode. See timeToFrames for an explanation of the t and isDuration arguments. The timecodeBase value, which defaults to 30, specifies the number of frames in one second. Parameters t timecodeBase isDuration Number Number Boolean Type String 5.3 timeToNTSCTimecode(t=time + thisComp. displayStartTime, ntscDropFrame=false, isDuration=false) Desciption Converts t to a String representing NTSC timecode. See timeToFrames for an explanation of the t and isDuration arguments. If ntscDropFrame is false (the default), the result String is NTSC non-drop-frame timecode. If ntscDropFrame is true, the result String is NTSC drop-frame timecode. Parameters 18 Chapter 5. Time conversion After Effects Expression Reference, Release 0.0.3 t ntscDropFrame isDuration Number Boolean Boolean Type String 5.4 timeToFeetAndFrames(t=time + thisComp. displayStartTime, fps=1.0 / thisComp.frameDuration, framesPerFoot=16, isDuration=false) Desciption Converts the value of t to a String representing feet of film and frames. See timeToFrames for an explanation of the t, fps, and isDuration arguments. The framesPerFoot argument specifies the number of frames in one foot of film. It defaults to 16, which is the most common rate for 35mm footage. Parameters t framesPerFoot isDuration Number Number Boolean Type String 5.5 timeToCurrentFormat(t=time + thisComp.displayStartTime, fps=1.0 / thisComp.frameDuration, isDuration=false) Desciption Converts the value of t to a String representing time in the current Project Settings display format. timeToFrames for a definition of all the arguments. See Note: An optional ntscDropFrame argument was added to the timeToCurrentFormat() function in After Effects CS5.5 and later. Default: ntscDropFrame=thisComp.ntscDropFrame. Parameters t fps isDuration Number Number Boolean 5.4. timeToFeetAndFrames(t=time + thisComp.displayStartTime, fps=1.0 / thisComp.frameDuration, framesPerFoot=16, isDuration=false) 19 After Effects Expression Reference, Release 0.0.3 Type String 20 Chapter 5. Time conversion CHAPTER 6 Vector Math Vector Math functions are global methods that perform operations on arrays, treating them as mathematical vectors. Unlike built-in JavaScript methods, such as Math.sin, these methods are not used with the Math prefix. Unless otherwise specified, Vector Math methods are lenient about dimensions and return a value that is the dimension of the largest input Array object, filling in missing elements with zeros. For example, the expression add([10, 20], [1, 2, 3]) returns [11, 22, 3]. Note: JJ Gifford’s website provides explanations and examples that show how to use simple geometry and trigonometry with expressions. 6.1 add(vec1, vec2) Description Adds two vectors. Parameters vec1 vec2 Array Array Type Array 21 After Effects Expression Reference, Release 0.0.3 6.2 sub(vec1, vec2) Description Subtracts two vectors. Parameters vec1 vec2 Array Array Type Array 6.3 mul(vec, amount) Description Multiplies every element of the vector by the amount. Parameters vec amount Array Number Type Array 6.4 div(vec, amount) Description Divides every element of the vector by the amount. Parameters vec amount Array Number Type Array 22 Chapter 6. Vector Math After Effects Expression Reference, Release 0.0.3 6.5 clamp(value, limit1, limit2) Description The value of each component of value is constrained to fall between the values of the corresponding values of limit1 and limit2. Parameters value limit1 limit2 Number or Array Number or Array Number or Array Type Number or Array 6.6 dot(vec1, vec2) Description Returns the dot (inner) product of the vector arguments. Parameters vec1 vec2 Array Array Type Number 6.7 cross(vec1, vec2) Description Returns the vector cross product of vec1 and vec2. Refer to a math reference or JavaScript guide for more information. Parameters vec1 vec2 Array (2- or 3-dimensional) Array (2- or 3-dimensional) Type Array (2- or 3-dimensional) 6.5. clamp(value, limit1, limit2) 23 After Effects Expression Reference, Release 0.0.3 6.8 normalize(vec) Description Normalizes the vector so that its length is 1.0. Using the normalize method is a short way of performing the operation div(vec, length(vec)). Parameters vec Array vec Array Type Array 6.9 length(vec) Description Returns the length of vector vec. Parameters Type Number 6.10 length(point1, point2) Description Returns the distance between two points. The point2 argument is optional. For example, length(point1, point2) is the same as length(sub(point1, point2)). For example, add this expression to the Focus Distance property of a camera to lock the focal plane to the camera’s point of interest so that the point of interest is in focus: length(position, pointOfInterest) Parameters point1 point2 Array Array Type Number 24 Chapter 6. Vector Math After Effects Expression Reference, Release 0.0.3 6.11 lookAt(fromPoint, atPoint) Description The argument fromPoint is the location in world space of the layer you want to orient. The argument atPoint is the point in world space you want to point the layer at. The return value can be used as an expression for the Orientation property, making the z-axis of the layer point at atPoint. This method is especially useful for cameras and lights. If you use this expression on a camera, turn off autoorientation. For example, this expression on the Orientation property of a spot light makes the light point at the anchor point of layer number 1 in the same composition: lookAt(position, thisComp.layer(1).position) Parameters fromPoint atPoint Array (3-dimensional) Array (3-dimensional) Type Array (3-dimensional) 6.11. lookAt(fromPoint, atPoint) 25 After Effects Expression Reference, Release 0.0.3 26 Chapter 6. Vector Math CHAPTER 7 Random Numbers Note: The wiggle method—which is used to randomly vary a property value—is in the Property attributes and methods category. See Property attributes and methods. 7.1 seedRandom(offset, timeless=false) Description The random and gaussRandom methods use a seed value that controls the sequence of numbers. By default, the seed is computed as a function of a unique layer identifier, the property within the layer, the current time, and an offset value of 0. Call seedRandom to set the offset to something other than 0 to create a different random sequence. Use true for the timeless argument to not use the current time as input to the random seed. Using true for the timeless argument allows you to generate a random number that doesn’t vary depending on the time of evaluation. The offset value, but not the timeless value, is also used to control the initial value of the wiggle function. For example, this expression on the Opacity property sets the Opacity value to a random value that does not vary with time: seedRandom(123456, true); random()*100 The multiplication by 100 in this example converts the value in the range 0-1 returned by the random method into a number in the range 0-100; this range is more typically useful for the Opacity property, which has values from 0% to 100%. Parameters offset timeless Number Boolean 27 After Effects Expression Reference, Release 0.0.3 Type None 7.2 random() Description Returns a random number in the range 0-1. Note: In After Effects CC and CS6, the behavior of random() is changed to be more random when layer IDs are close together. The wiggle() expression is not affected. Type Number 7.3 random(maxValOrArray) Description If maxValOrArray is a Number, this method returns a number in the range from 0 to maxValOrArray. If maxValOrArray is an Array, this method returns an Array with the same dimension as maxValOrArray, with each component ranging from 0 to the corresponding component of maxValOrArray. Parameters maxValOrArray Number or Array Type Number or Array 7.4 random(minValOrArray, maxValOrArray) Description If minValOrArray and maxValOrArray are Numbers, this method returns a number in the range from minValOrArray to maxValOrArray. If the arguments are Arrays, this method returns an Array with the same dimension as the argument with the greater dimension, with each component in the range from the corresponding component of minValOrArray to the corresponding component of maxValOrArray. For example, the expression random([100, 200], [300, 400]) returns an Array whose first value is in the range 100-300 and whose second value is in the range 200-400. If the dimensions of the two input Arrays don’t match, higher-dimension values of the shorter Array are filled out with zeros. 28 Chapter 7. Random Numbers After Effects Expression Reference, Release 0.0.3 Parameters minValOrArray maxValOrArray Number or Array Number or Array Type Number or Array 7.5 gaussRandom() Description The results have a Gaussian (bell-shaped) distribution. Approximately 90% of the results are in the range 0-1, and the remaining 10% are outside this range. Type Number 7.6 gaussRandom(maxValOrArray) Description When maxValOrArray is a Number, this method returns a random number. Approximately 90% of the results are in the 0 to maxValOrArray range, and the remaining 10% are outside this range. When maxValOrArray is an Array, this method returns an Array of random values, with the same dimension as maxValOrArray. 90% of the values are in the range from 0 to maxValOrArray, and the remaining 10% are outside this range. The results have a Gaussian (bell-shaped) distribution. Parameters maxValOrArray Number or Array Type Number or Array 7.7 gaussRandom(minValOrArray, maxValOrArray) Description If minValOrArray and maxValOrArray are Numbers, this method returns a random number. Approximately 90% of the results are in the range from minValOrArray to maxValOrArray, and the remaining 10% are outside this range. 7.5. gaussRandom() 29 After Effects Expression Reference, Release 0.0.3 If the arguments are Arrays, this method returns an Array of random numbers with the same dimension as the argument with the greater dimension. For each component, approximately 90%``of the results are in the range from the corresponding component of ``minValOrArray to the corresponding component of maxValOrArray, and the remaining 10% are outside this range. The results have a Gaussian (bell-shaped) distribution. Parameters minValOrArray maxValOrArray Number or Array Number or Array Type Number or Array 7.8 noise(valOrArray) Description Returns a number in the range from -1 to 1. The noise is not actually random; it is based on Perlin noise, which means that the return values for two input values that are near one another tend to be near one another. This type of noise is useful when you want a sequence of seemingly random numbers that don’t vary wildly from one to the other—as is usually the case when animating any apparently random natural motion. Example: rotation + 360*noise(time) Parameters valOrArray Number or an Array (2- or 3-dimensional) Type Number 30 Chapter 7. Random Numbers CHAPTER 8 Interpolation Description For all the Interpolation methods, the argument t is often time or value, though it can have other values, instead. If t is time, the interpolation between values happens over a duration. If t is value, then the expression maps one range of values to a new range of values. For additional explanations and examples of the Interpolation methods, see JJ Gifford’s website. Chris and Trish Meyer provide additional information and examples for these methods in an article on the ProVideo Coalition website. Ian Haigh provides a script on After Effects Scripts website that you can use to easily apply advanced interpolation method expressions—such as bounces—to properties. Andrew Devis provides a pair of video tutorials on the Creative COW website that show in detail how to use the linear expression method along with the Convert Audio To Keyframes command. 8.1 linear(t, tMin, tMax, value1, value2) Description Returns value1 when t <= tMin. Returns value2 when t >= tMax. Returns a linear interpolation between value1 and value2 when tMin < t < tMax. For example, this expression on the Opacity property causes Opacity values to ramp linearly from 20% to 80% over the time from 0 seconds to 6 seconds: linear(time, 0, 6, 20, 80) This method—like all the Interpolation methods—can also be used to convert from one range of values to another. For example, this expression on the Opacity property converts the Opacity values from the range 0%-100% to the range 20%-80%: 31 After Effects Expression Reference, Release 0.0.3 linear(value, 0, 100, 20, 80) Parameters t tMin tMax value1 value2 Number Number Number Number or Array Number or Array Type Number or Array 8.2 linear(t, value1, value2) Description Returns a value that linearly interpolates from value1 to value2 as t ranges from 0 to 1. Returns value1 when t <= 0. Returns value2 when t >= 1. Parameters t value1 value2 Number Number or Array Number or Array Type Number or Array 8.3 ease(t, value1, value2) Description Similar to linear with the same arguments, except that the interpolation eases in and out so that the velocity is 0 at the start and end points. This method results in a smooth animation. Parameters t value1 value2 Number Number or Array Number or Array Type Number or Array 32 Chapter 8. Interpolation After Effects Expression Reference, Release 0.0.3 8.4 ease(t, tMin, tMax, value1, value2) Description Similar to linear with the same arguments, except that the interpolation eases in and out so that the velocity is 0 at the start and end points. This method results in a smooth animation. Parameters t tMin tMax value1 value2 Number Number Number Number or Array Number or Array Type Number or Array 8.5 easeIn(t, value1, value2) Description Similar to ease, except that the tangent is 0 only on the value1 side and interpolation is linear on the value2 side. Parameters t value1 value2 Number Number or Array Number or Array Type Number or Array 8.6 easeIn(t, tMin, tMax, value1, value2) Description Similar to ease, except that the tangent is 0 only on the tMin side and interpolation is linear on the tMax side. Parameters t tMin tMax value1 value2 8.4. ease(t, tMin, tMax, value1, value2) Number Number Number Number or Array Number or Array 33 After Effects Expression Reference, Release 0.0.3 Type Number or Array 8.7 easeOut(t, value1, value2) Description Similar to ease, except that the tangent is 0 only on the value2 side and interpolation is linear on the value1 side. Parameters t value1 value2 Number Number or Array Number or Array Type Number or Array 8.8 easeOut(t, tMin, tMax, value1, value2) Description Similar to ease, except that the tangent is 0 only on the tMax side and interpolation is linear on the tMin side. Parameters t tMin tMax value1 value2 Number Number Number Number or Array Number or Array Type Number or Array 34 Chapter 8. Interpolation CHAPTER 9 Color Conversion Harry Frank provides a video tutorial on his graymachine website that shows how to use these color conversion methods to change the color of the waves produced by the Radio Waves effect. 9.1 rgbToHsl(rgbaArray) Description Converts a color in RGBA space to HSLA space. The input is an Array of normalized red, green, blue, and alpha channel values, all in the range of 0.0 to 1.0. The resulting value is an Array of hue, saturation, lightness, and alpha channel values, also in the range of 0.0 to 1.0. Example: rgbToHsl.effect("Change Color")("Color To Change") Parameters rgbaArray Array (4-dimensional) Type Array (4-dimensional) 9.2 hslToRgb(hslaArray) Description 35 After Effects Expression Reference, Release 0.0.3 Converts a color in HSLA space to RGBA space. This conversion is the opposite of the conversion performed by the rgbToHsl method. Parameters hslaArray Array (4-dimensional) Type Array (4-dimensional) 36 Chapter 9. Color Conversion CHAPTER 10 Other Math 10.1 degreesToRadians(degrees) Description Converts degrees to radians. Parameters degrees Number Type Number 10.2 radiansToDegrees(radians) Description Converts radians to degrees. Parameters radians Number Type Number 37 After Effects Expression Reference, Release 0.0.3 38 Chapter 10. Other Math CHAPTER 11 Project 11.1 Project.fullPath Description The platform-specific absolute file path, including the project file name. If the project has not been saved, it returns an empty string. Example: thisProject.fullPath Type String 11.2 Project.bitsPerChannel Description The color depth of the project in bits per channel (bpc), as set in Project Settings > Color Management They are one of 8, 16, or 32. Equivalent to the scripting project attribute app.project.bitsPerChannel. Example: thisProject.bitsPerChannel Type Number 39 After Effects Expression Reference, Release 0.0.3 11.3 Project.linearBlending Description The state of the Blend Colors Using 1.0 Gamma option in Project Settings > Color Management. Equivalent to the scripting project attribute app.project.linearBlending. Example: thisProject.linearBlending Type Boolean 40 Chapter 11. Project CHAPTER 12 Comp 12.1 Comp.layer(index) Description Retrieves the layer by number (order in the Timeline panel). Example: thisComp.layer(3) Parameters index Number Type Layer, Light, or Camera 12.2 Comp.layer(name) Description Retrieves the layer by name. Names are matched according to layer name, or source name if there is no layer name. If duplicate names exist, After Effects uses the first (topmost) one in the Timeline panel. Example: thisComp.layer("Solid 1") 41 After Effects Expression Reference, Release 0.0.3 Parameters name String Type Layer, Light, or Camera 12.3 Comp.layer(otherLayer, relIndex) Description Retrieves the layer that is relIndex layers above or below otherLayer. For example, thisComp. layer(thisLayer, 1).active returns true if the next layer down in the Timeline panel is active. Parameters otherLayer relIndex Layer Object Number Type Layer, Light, or Camera 12.4 Comp.marker Description Note: You cannot access a composition marker by marker number. If you have a project created in a previous version of After Effects that uses composition marker numbers in expressions, you must change those calls to use marker.key(name) instead. Because the default name of a composition marker is a number, converting the reference to use the name is often just a matter of surrounding the number with quotation marks. Type MarkerProperty 12.5 Comp.marker.key(index) Description Returns the MarkerKey object of the marker with the specified index. The index refers to the order of the marker in composition time, not to the name of the marker. For example, this expression returns the time of the first composition marker: 42 Chapter 12. Comp After Effects Expression Reference, Release 0.0.3 thisComp.marker.key(1).time Parameters Number index Type MarkerKey 12.6 Comp.marker.key(name) Description Returns the MarkerKey object of the marker with the specified name. The name value is the name of the marker, as typed in the comment field in the marker dialog box, for example, marker.key(“1”). For a composition marker, the default name is a number. If more than one marker in the composition has the same name, this method returns the marker that occurs first in time (in composition time). The value for a marker key is a String, not a Number. For example, this expression returns the time of the composition marker with the name “0”: thisComp.marker.key("0").time Parameters name String Type MarkerKey 12.7 Comp.marker.nearestKey(t) Description Returns the marker that is nearest in time to t. For example, this expression returns the time of the composition marker nearest to the time of 1 second: thisComp.marker.nearestKey(1).time This expression returns the time of the composition marker nearest to the current time: thisComp.marker.nearestKey(time).time Parameters t 12.6. Comp.marker.key(name) Number 43 After Effects Expression Reference, Release 0.0.3 Type MarkerKey 12.8 Comp.marker.numKeys Description Returns the total number of composition markers in the composition. Type Number 12.9 Comp.numLayers Description Returns the number of layers in the composition. Type Number 12.10 Comp.activeCamera Description Returns the Camera object for the camera through which the composition is rendered at the current frame. This camera is not necessarily the camera through which you are looking in the Composition panel. Type Camera 12.11 Comp.width Description Returns the composition width, in pixels.Apply the following expression to the Position property of a layer to center the layer in the composition frame: [thisComp.width/2, thisComp.height/2] Type Number 44 Chapter 12. Comp After Effects Expression Reference, Release 0.0.3 12.12 Comp.height Description Returns the composition height, in pixels. Type Number 12.13 Comp.duration Description Returns the composition duration, in seconds. Type Number 12.14 Comp.ntscDropFrame Description Returns true if the timecode is in drop-frame format. Note: Available in After Effects CS5.5 and later. Type Boolean 12.15 Comp.displayStartTime Description Returns the composition start time, in seconds. Type Number 12.12. Comp.height 45 After Effects Expression Reference, Release 0.0.3 12.16 Comp.frameDuration Description Returns the duration of a frame, in seconds. Type Number 12.17 Comp.shutterAngle Description Returns the shutter-angle value of the composition, in degrees. Type Number 12.18 Comp.shutterPhase Description Returns the shutter phase of the composition, in degrees. Type Number 12.19 Comp.bgColor Description Returns the background color of the composition. Type Array (4-dimensional) 12.20 Comp.pixelAspect Description Returns the pixel aspect ratio of the composition. Type Number 46 Chapter 12. Comp After Effects Expression Reference, Release 0.0.3 12.21 Comp.name Description Returns the name of the composition. Type String 12.21. Comp.name 47 After Effects Expression Reference, Release 0.0.3 48 Chapter 12. Comp CHAPTER 13 Footage Description To use a footage item from the Project panel as an object in an expression, use the global footage method, as in footage("file_name"). You can also access a footage object using the source attribute on a layer whose source is a footage item. 13.1 Footage.width Description Returns the width of the footage item, in pixels. Type Number 13.2 Footage.height Description Returns the height of the footage item, in pixels. Type Number 49 After Effects Expression Reference, Release 0.0.3 13.3 Footage.duration Description Returns the duration of the footage item, in seconds. Type Number 13.4 Footage.frameDuration Description Returns the duration of a frame in the footage item, in seconds. Type Number 13.5 Footage.ntscDropFrame Description Returns true if the timecode is in drop-frame format. (After Effects CS5.5 and later.) Type Boolean 13.6 Footage.pixelAspect Description Returns the pixel aspect ratio of the footage item. Type Number 13.7 Footage.name Description Returns the name of the footage item as shown in the Project panel. Type String 50 Chapter 13. Footage CHAPTER 14 Camera Camera objects have the same attributes and methods as Layer objects, except for: • source • effect • mask • width • height • anchorPoint • scale • opacity • audioLevels • timeRemap • all the material properties 14.1 Camera.pointOfInterest Description Returns the point of interest values of a camera in world space. Type Array (3 dimensional) 51 After Effects Expression Reference, Release 0.0.3 14.2 Camera.zoom Description Returns the zoom values of a camera in pixels. Here’s an expression for the Scale property of a layer that maintains the relative size of the layer in frame while changing the z position (depth) of a layer or the Zoom value of a camera: cam = thisComp.activeCamera; distance = length(sub(position, cam.position)); scale * distance / cam.zoom; Type Number 14.3 Camera.depthOfField Description Returns 1 if the Depth Of Field property of a camera is on, or returns 0 if the Depth Of Field property is off. Type Boolean Number 14.4 Camera.focusDistance Description Returns the focus distance value of a camera, in pixels. Type Number 14.5 Camera.aperture Description Returns the aperture value of a camera, in pixels. Type Number 52 Chapter 14. Camera After Effects Expression Reference, Release 0.0.3 14.6 Camera.blurLevel Description Returns the blur level value of a camera as a percentage. Type Number 14.7 Camera.active Description Returns true if the camera: 1. is the active camera for the composition at the current time: the video switch for the camera layer is on 2. the current time is in the range from the in point of the camera layer to the out point of the camera layer 3. and it is the first (topmost) such camera layer listed in the timeline panel Returns false otherwise. Type Boolean 14.6. Camera.blurLevel 53 After Effects Expression Reference, Release 0.0.3 54 Chapter 14. Camera CHAPTER 15 Light Description Light objects have the same attributes and methods as Layer objects, except for: • source • effect • mask • width • height • anchorPoint • scale • opacity • audioLevels • timeRemap • all the material properties Note: David Van Brink provides an instructional article and sample project on his omino pixel blog that shows how to use expressions with lights. 15.1 Light.pointOfInterest Description Returns the point of interest values for a light in world space. 55 After Effects Expression Reference, Release 0.0.3 Type Array (3-dimensional) 15.2 Light.intensity Description Returns the intensity values of a light as a percentage. Type Number 15.3 Light.color Description Returns the color value of a light. Type Array (4-dimensional) 15.4 Light.coneAngle Description Returns the cone angle of a light, in degrees. Type Number 15.5 Light.coneFeather Description Returns the cone feather value of a light as a percentage. Type Number 56 Chapter 15. Light After Effects Expression Reference, Release 0.0.3 15.6 Light.shadowDarkness Description Returns the shadow darkness value of a light as a percentage. Type Number 15.7 Light.shadowDiffusion Description Returns the shadow diffusion value of a light, in pixels. Type Number 15.6. Light.shadowDarkness 57 After Effects Expression Reference, Release 0.0.3 58 Chapter 15. Light CHAPTER 16 Effect 16.1 Effect.active Description Returns true if the effect is turned on (the effect switch is selected). Type Boolean 16.2 Effect.param(name) Description Returns a property within an effect. Effect control points are always in layer space. Example: effect("Bulge").param("Bulge Height") Parameters name String Type Property 59 After Effects Expression Reference, Release 0.0.3 16.3 Effect.param(index) Description Returns a property within an effect. Effect control points are always in layer space. fect(“Bulge”).param(4) returns the Bulge Height property. For example, ef- Parameters index Number Type Property 60 Chapter 16. Effect CHAPTER 17 Mask Note: You can link Mask Path properties to other path properties (paths in a shape layer and brush strokes), but the properties are not accessible for direct numerical manipulation through expressions. 17.1 Mask.maskOpacity Description Returns the opacity value of a mask as a percentage. Type Number 17.2 Mask.maskFeather Description Returns the feather value of a mask, in pixels. Type Number 61 After Effects Expression Reference, Release 0.0.3 17.3 Mask.maskExpansion Description Returns the expansion value of a mask, in pixels. Type Number 17.4 Mask.invert Description Returns true if the mask is inverted or false if it is not. Type Boolean 62 Chapter 17. Mask CHAPTER 18 Property Example: Animating with the propertyGroup method and propertyIndex attribute [image] In this example, the propertyGroup method for each brush stroke targets the Brush property group because that group is two property groups up from the Rotation property. The propertyIndex attribute in each Brush stroke then returns a unique value for each Brush stroke. The resulting value is then multiplied by the time and 200 and applied to each rotation value, rotating each brush stroke differently, creating swirling paint strokes: propertyGroup(2).propertyIndex * time * 200 propertyGroup(2).propertyIndex * time * 200 [image] 18.1 value Description Returns the value of a property at the current time. Type Number, Array, or String 18.2 valueAtTime(t) Description Returns the value of a property at the specified time, in seconds. 63 After Effects Expression Reference, Release 0.0.3 For example, to have a property value for each frame chosen randomly from a set of four values, set your four values as keyframes at 0, 1, 2, and 3 seconds, and then apply the following expression to the property: valueAtTime(random(4)) Note: Dan Ebberts provides more examples and techniques for using the valueAtTime and velocityAtTime methods on his MotionScript website. Parameters t Number Type Number or Array 18.3 velocity Description Returns the temporal velocity value at the current time. For spatial properties, such as Position, it returns the tangent vector value. The result is the same dimension as the property. Type Number or Array 18.4 velocityAtTime(t) Description Returns the temporal velocity value at the specified time. Parameters t Number Type Number or Array 64 Chapter 18. Property After Effects Expression Reference, Release 0.0.3 18.5 speed Description Returns a 1D, positive speed value equal to the speed at which the property is changing at the default time. This element can be used only for spatial properties. Type Number 18.6 speedAtTime(t) Description Returns the spatial speed value at the specified time. Parameters t Number Type Number 18.7 wiggle(freq, amp, octaves=1, amp_mult=0.5, t=time) Description Randomly shakes (wiggles) the value of the property. freq value is the frequency in wiggles per second. amp value is the amplitude in units of the property to which it is applied. octaves is the number of octaves of noise to add together. This value controls how much detail is in the wiggle. Make this value higher than the default of 1 to include higher frequencies or lower to include amplitude harmonics in the wiggle. amp_mult is the amount that amp is multiplied by for each octave. This value controls how fast the harmonics drop off. The default is 0.5; make it closer to 1 to have the harmonics added at the same amplitude as the base frequency, or closer to 0 to add in less detail. t is the base start time. This value defaults to the current time. Use this parameter if you want the output to be a wiggle of the property value sampled at a different time. Example: position.wiggle(5, 20, 3, 0.5) This produces about 5 wiggles per second with an average size of about 20 pixels. In addition to the main wiggle, two more levels of detailed wiggles occur with a frequency of 10 and 20 wiggles per second, and sizes of 10 and 5 pixels, respectively. This example, on a two-dimensional property such as Scale, wiggles both dimensions by the same amount: 18.5. speed 65 After Effects Expression Reference, Release 0.0.3 v = wiggle(5, 10); [v[0], v[0]] This example, on a two-dimensional property, wiggles only along the y-axis: freq = 3; amp = 50; w = wiggle(freq,amp); [value[0],w[1]]; Note: Dan Ebberts provides an example expression and a detailed explanation on his MotionScript website that shows how to use the time parameter of the wiggle method to create a looping animation. Parameters freq amp octaves amp_mult t Number Number Number Number Number Type Number or Array 18.8 temporalWiggle(freq, t=time) amp, octaves=1, amp_mult=0.5, Description Samples the property at a wiggled time. freq value is the frequency in wiggles per second. amp is the amplitude in units of the property to which it is applied. octaves is the number of octaves of noise to add together. amp_mult is the amount that amp is multiplied by for each octave t is the base start time. For this function to be meaningful, the property it samples must be animated, because the function alters only the time of sampling, not the value. Example: scale.temporalWiggle(5, 0.2) Parameters 66 Chapter 18. Property After Effects Expression Reference, Release 0.0.3 freq amp octaves amp_mult t Number Number Number Number Number Type Number or Array 18.9 smooth(width=.2, samples=5, t=time) Description Smooths the property values over time, converting large, brief deviations in the value to smaller, more evenly distributed deviations. This smoothing is accomplished by applying a box filter to the value of the property at the specified time. The width value is the range of time (in seconds) over which the filter is averaged. The samples value is the number of discrete samples evenly spaced over time; use a larger value for greater smoothness (but decreased performance). Generally, you’ll want samples to be an odd number so that the value at the current time is included in the average. Example: position.smooth(0.1, 5) Parameters width samples t Number Number Number Type Number or Array 18.10 loopIn(type="cycle", numKeyframes=0) Description Loops a segment of time that is measured from the first keyframe on the layer forward toward the Out point of the layer. The loop plays from the In point of the layer. The numKeyframes value determines what segment is looped: The segment looped is the portion of the layer from the first keyframe to the numKeyframes+1 keyframe. For example, loopIn(“cycle”, 3) loops the segment bounded by the first and fourth keyframes. The default value of 0 means that all keyframes loop. You can use keyframe-looping methods to repeat a series of keyframes. You can use these methods on most properties. Exceptions include properties that can’t be expressed by simple numeric values in the Timeline panel, such as the Source Text property, path shape properties, and the Histogram property for the Levels effect. Keyframes or duration values that are too large are clipped to the maximum allowable value. Values that are too small result in a constant loop. 18.9. smooth(width=.2, samples=5, t=time) 67 After Effects Expression Reference, Release 0.0.3 type cycle pingpong offset continue result (default) Repeats the specified segment. Repeats the specified segment, alternating between forward and backward. Repeats the specified segment, but offsets each cycle by the difference in the value of the property at the start and end of the segment, multiplied by the number of times the segment has looped. Does not repeat the specified segment, but continues to animate a property based on the velocity at the first or last keyframe. For example, if the last keyframe of a Scale property of a layer is 100%, the layer continues to scale from 100% to the Out point, instead of looping directly back to the Out point. This type does not accept a keyframes or duration argument. Tip: Use loopIn("continue") + loopOut("continue") - value to have a continued motion before and after the property’s keyframes. Tip from Paul Slemmer. Type Number or Array 18.11 loopOut(type="cycle", numKeyframes=0) Description Loops a segment of time that is measured from the last keyframe on the layer back toward the In point of the layer. The loop plays until the Out point of the layer. The specified number of keyframes determines the segment to loop. The numKeyframes value sets the number of keyframe segments to loop; the specified range is measured backward from the last keyframe. For example, loopOut("cycle", 1) loops the segment bounded by the last keyframe and second-to-last keyframe. The default value of 0 means that all keyframes loop. See the entry for loopIn for more information. Note: David Van Brink provides an instructional article and sample project on his omino pixel blog that show how to use the Echo effect, the Particle Playground effect, and the loopOut method to animate a swarm of stylized swimming bacteria. Type Number or Array 18.12 loopInDuration(type="cycle", duration=0) Description Loops a segment of time that is measured from the first keyframe on the layer forward toward the Out point of the layer. The loop plays from the In point of the layer. Specified duration determines the segment to loop. The duration 68 Chapter 18. Property After Effects Expression Reference, Release 0.0.3 value sets the number of composition seconds in a segment to loop; the specified range is measured from the first keyframe. For example, loopInDuration("cycle", 1) loops the first second of the entire animation. The default of 0 means that the segment to loop begins at the layer Out point. See the entry for loopIn for more information. Type Number or Array 18.13 loopOutDuration(type="cycle", duration=0) Description Loops a segment of time that is measured from the last keyframe on the layer back toward the In point of the layer. The loop plays until the Out point of the layer. Specified duration determines the segmetn to loop. The duration value sets the number of composition seconds in a segment to loop; the specified range is measured backward from the last keyframe. For example, loopOutDuration("cycle", 1) loops the last second of the entire animation. The default of 0 means that the segment to loop begins at the layer In point. See the entry for loopIn for more information. Type Number or Array 18.14 key(index) Description Returns the Key or MarkerKey object by number. For example, key(1) returns the first keyframe. Parameters index Number Type Key or MarkerKey 18.15 key(markerName) Description Returns the MarkerKey object with this name. Use only on marker properties. markerName String 18.13. loopOutDuration(type="cycle", duration=0) 69 After Effects Expression Reference, Release 0.0.3 Type MarkerKey 18.16 nearestKey(t) Description Returns the Key or MarkerKey object nearest to a designated time t. Parameters t Number Type Key or MarkerKey 18.17 numKeys Description Returns the number of keyframes on a property. Returns the number of markers on a marker property. Note: If you use the Separate Dimensions command to separate the dimensions of the Position property into individual components, the number of keyframes changes, so the value returned by this method changes. Type Number 18.18 propertyGroup(countUp=1) Description Returns a group of properties relative to the property on which the expression is written. For example, if you add the propertyGroup(1) expression to the Rotation property of a brush stroke, the expression targets the Transform property group, which contains the Rotation property. If you add propertyGroup(2) instead, the expression targets the Brush property group. This method lets you establish name-independent relationships in the property hierarchy. It is especially useful when duplicating properties that contain expressions.The numProperties method for propertyGroup returns the number of properties in the property group. This example returns the number of properties in the group that contains the property on which the expression is written: 70 Chapter 18. Property After Effects Expression Reference, Release 0.0.3 thisProperty.propertyGroup(1).numProperties Type Group 18.19 propertyIndex Description Returns the index of a property relative to other properties in its property group, including property groups within masks, effects, text animators, selectors, shapes, trackers, and track points. Type Number 18.20 name Description Returns the name of the property or property group. Type String 18.19. propertyIndex 71 After Effects Expression Reference, Release 0.0.3 72 Chapter 18. Property CHAPTER 19 Path Property Note: Available in After Effects CC18 and later. Example 1 Writes the list of point and tangent coordinates from Path 1 of Shape 1 on layer Shape Layer 1, at time=0, into a string. Apply this to the source text property of a text layer for a readout of the coordinates and incoming and outgoing tangents of the shape. pointsList = ""; sampleTime = 0; myShape = thisComp.layer("Shape Layer 1").content("Shape 1").content("Path 1").path; for (i = 0; i < myShape.points(sampleTime).length; i++) { pointsList += "c: " + myShape.points(sampleTime)[i].toString() + " i: " + ˓→myShape.inTangents(sampleTime)[i].toString() + " o: " + myShape. ˓→outTangents(sampleTime)[i].toString() + "\n"; } pointsList; Example 2 Reads the coordinates of the first vertex of Mask 1 on Dark Gray Solid 1 and converts them to composition coordinates. Apply this to a 2D point control of an effect, such as Write-on or CC Particle Systems II, to make the effect trace or track the first point of an animated mask. Duplicate the effect and change the path points index value ([0]) to trace or track the other points of the mask. myLayer = thisComp.layer("Dark Gray Solid 1"); myLayer.toComp(myLayer.mask("Mask 1").maskPath.points()[0]); 73 After Effects Expression Reference, Release 0.0.3 19.1 name Description Returns the name of the property. Type String 19.2 pathProperty.points(t=time) Description Get the x,y coordinates of all points on a path. Coordinates for layer mask path points are relative to the layer’s origin in its upper-left hand corner. Coordinates for Bezier shape path points are are relative to the anchor point of the path’s shape group (ex., “Transform: Shape 1 > Anchor Point”). Coordinates for brush stroke path points are relative to the start of the stroke; the first point is [0,0]. This method can be passed into the createPath() method for the points parameter when duplicating a path. Optionally specify the time at which sample to the path. Parameters t Number Type Array of number pair arrays, rounded to the fourth decimal place 19.3 pathProperty.inTangents(t=time) Description Get the x,y coordinates of the incoming tangent handle for all points on a path. Tangent coordinate values are offset relative to the parent point’s coordinates. i.e., The value [0,0] creates no curvature at the incoming tangent. This method can be passed into the createPath() method for the inTangents parameter when duplicating a path. Optionally specify the time at which sample to the path. Type Array of number pair arrays, rounded to the fourth decimal place 74 Chapter 19. Path Property After Effects Expression Reference, Release 0.0.3 19.4 pathProperty.outTangents(t=time) Description Get the x, y coordinates of the outgoing tangent handle for all points on a path. Tangent coordinate values are offset relative to the parent point’s coordinates. i.e., The value [0,0] creates no curvature at the outgoing tangent. This method can be passed into the createPath() method for the outTangents parameter when duplicating a path. Optionally specify the time at which sample to the path. Parameters t Number Type Array of number pair arrays, rounded to the fourth decimal place 19.5 pathProperty.isClosed() Description Determines if the path is open or closed. Returns true if the path is closed, false if the path is open. This method can be passed into the createPath() method for the is_closed parameter when duplicating a path. Type Boolean 19.6 pathProperty.pointOnPath(percentage=0.5, t=time) Description Get the x, y coordinates of an arbitrary point along a path. The point is expressed as a percentage of the arc-length of the path. 0% is the first point and 100% is the last point. When the path is closed, 0% and 100% will return the same coordinates. Percentage of arc-length is used to ensure uniform speed along the path. Other than 0% and 100%, percentages do not necessarily correlate with the Bezier points on the path. (i.e., For a path with three points, the second point will not necessarily be at 50%.) This also means that for an open path and closed path with identical points, the percentage along the open path will not return the same coordinates as the closed path due to the additional length of the closed path. Optionally specify the time at which sample to the path. Parameters percentage t Number Number Type A number pair array 19.4. pathProperty.outTangents(t=time) 75 After Effects Expression Reference, Release 0.0.3 19.7 pathProperty.tangentOnPath(percentage=0.5, t=time) Description Get the calculated x,y coordinates of the outgoing tangent handle for an arbitrary point along a path. Tangent coordinate values are offset relative to the parent point’s coordinates. i.e., The value [0,0] creates no curvature at the outgoing tangent. The incoming tangent handle is the inverse of this value (multiply the x,y coordinates by -1). The tangent’s parent point is expressed as a percentage of the arc-length of the path. Read the description of the pointOnPath() method for details about arc-length percentage. The coordinates returned by tangentOnPath() are calcuated from it’s parent point and will differ from those returned by outTangents() if a user-defined point also exists at that arc-length pecentage. The linear distance between the parent point’s coordinates and tangentOnPath() coordinates will always be 1. You can multiply the returned coordinates to create a longer tangent, for example (myPath.tangentOnPath() * 100). Optionally specify the time at which sample to the path. Parameters percentage t Number Number Type A number pair array 19.8 pathProperty.normalOnPath(percentage=0.5, t=time) Description Get the calculated x,y coordinates of the normal for an arbitrary point along a path. Coordinate values of normals are offset relative to the parent point’s coordinates. i.e., The value [0,0] is the same as the parent point. The normal’s parent point is expressed as a percentage of the arc-length of the path. Read the description of the pointOnPath() method for details about arc-length percentage. The coordinates returned by normalOnPath() are calcuated from its parent point. The linear distance between the parent point’s coordinates and normalOnPath() coordinates will always be 1. You can multiply the returned coordinates to create a longer normal, for example. (myPath. normalOnPath() * 100). Optionally specify the time at which sample to the path. Parameters percentage t Number Number Type A number pair array 76 Chapter 19. Path Property After Effects Expression Reference, Release 0.0.3 19.9 pathProperty.createPath(points=[[0,0], [100,0], [100, 100], [0,100]], inTangents=[], outTangents=[], is_closed=true) Description Creates a path object from a set of points and tangents. The points are defined by an array of number pair arrays representing their x, y coordinates. The array length must be at least 1, and can be of any greater length. The incoming and outgoing tangent handles of the points are defined by an array of number pair arrays representing their x, y offset coordinates. The length of the tangent arrays must be exactly the same as the points parameter. Tangent coordinate values are offset relative to the parent point’s coordinates. i.e., The value [0,0] creates no curvature at the incoming tangent. The points(), inTangents(), outTangents(), and isClosed() methods of a path can be passed into the points, inTangents, outTangents, and is_closed parameters to duplicate a path. The points and tangents of the same path can be passed into createPath() with modifications to generate a different result. For example, the following expression will remove curves from Mask 1 by not passing the inTangents or outTangents parameters: myMask = mask("Mask 1").path; myMask.createPath(myMask.points()); The following example passes the points and tangents of Mask 1 and converts it to an open path by setting is_closed to false: myMask = mask("Mask 1").path; myMask.createPath(myMask.points(), myMask.inTangents(), myMask.outTangents(), false); Parameters points inTangents outTangents is_closed Array Array Array Boolean Type Path 19.9. pathProperty.createPath(points=[[0,0], [100,0], [100,100], [0,100]], inTangents=[], outTangents=[], is_closed=true) 77 After Effects Expression Reference, Release 0.0.3 78 Chapter 19. Path Property CHAPTER 20 Key Description When you access a Key object, you can get time, index, and value properties from it. For example, the following expression gives you the value of the third Position keyframe: position.key(3).value. The following expression, when written on an Opacity property with keyframes, ignores the keyframe values and uses only the placement of the keyframes in time to determine where a flash should occur: d = Math.abs(time - nearestKey(time).time); easeOut(d, 0, .1, 100, 0) 20.1 Key.value Description Returns the value of the keyframe. Type Number or Array 20.2 Key.time Description Returns the time of the keyframe. Type Number 79 After Effects Expression Reference, Release 0.0.3 20.3 Key.index Description Returns the index of the keyframe. Type Number 80 Chapter 20. Key CHAPTER 21 MarkerKey You can access values for composition markers and layer markers using the same methods. Access layer markers through the thisLayer.marker object; access composition markers through the thisComp.marker object. For the purpose of expressions, markers are a special type of Key object, so you can use methods such as nearestKey(time) to access markers, and markers also have time and index attributes. The index attribute is not the number (name) of the marker; it is the keyframe index number, representing the order of the marker in the time ruler. Expressions have access to all the values for a marker that you can set in the Composition Marker or Layer Marker dialog box. This expression on the Source Text property of a text layer displays the time, duration, index, comment (name), chapter, URL, frame target, and cue point name for the layer marker nearest the current time, and whether the marker is for an event cue point: m = thisLayer.marker.nearestKey(time); s = "time:" + timeToCurrentFormat(m.time) + "\r" + "duration: " + m.duration + "\r" + "key index: " + m.index + "\r" + "comment:" + m.comment + "\r" + "chapter:" + m.chapter + "\r" + "URL:" + m.url + "\r" + "frame target: " + m.frameTarget + "\r" + "cue point name: " + m.cuePointName + "\r" + "Event cue point? " + m.eventCuePoint + "\r"; for (param in m.parameters){ s += "parameter: " + param + " value: " + m.parameters[param] + "\r"; } s Because the XMP metadata in a footage item can be converted into layer markers for a layer based on that item, expressions can interact with XMP metadata. For information, see XMP metadata in After Effects. Dan Ebberts provides a tutorial on the After Effects Developer Center that includes an example of using XMP metadata with expressions. 81 After Effects Expression Reference, Release 0.0.3 21.1 Marker.duration Description Duration, in seconds, of marker. Type Number 21.2 Marker.comment Description Contents of Comment field in marker dialog box. Type String 21.3 Marker.chapter Description Contents of Chapter field in marker dialog box. Type String 21.4 Marker.url Description Contents of URL field in marker dialog box. Type String 82 Chapter 21. MarkerKey After Effects Expression Reference, Release 0.0.3 21.5 Marker.frameTarget Description Contents of Frame Target field in marker dialog box. Type String 21.6 Marker.eventCuePoint Description Setting for cue point type in marker dialog box. True for Event; false for Navigation. Type Boolean 21.7 Marker.cuePointName Description Contents of cue point Name field in marker dialog box. Type String 21.8 Marker.parameters Description Contents of Parameter Name and Parameter Value fields in marker dialog box. For example, if you have a parameter named “background color”, then you can use the following expression to access its value at the nearest marker: thisComp.marker.nearestKey(time).parameters["background color"] Type Associative array of String values 21.5. Marker.frameTarget 83 After Effects Expression Reference, Release 0.0.3 84 Chapter 21. MarkerKey CHAPTER 22 Layer Sub-objects Note: For After Effects CC and CS6, the Expression language menu, the “Layer Sub-objects”, “Layer General”, “Layer Properties”, “Layer 3D”, and “Layer Space Transforms” have been arranged into a “Layer” submenu. 22.1 Layer.source Description Returns the source Comp or source Footage object for the layer. Default time is adjusted to the time in the source. Example: source.layer(1).position Type Comp or Footage 22.2 Layer.sourceTime(t=time) Description Returns the layer source corresponding to time t. Note: After Effects CS5.5 and later 85 After Effects Expression Reference, Release 0.0.3 Parameters t Number Type Number 22.3 Layer.sourceRectAtTime(t = time, includeExtents = false) Description Returns a JavaScript object with four attributes: [top, left, width, height] Extents apply only to shape layers and paragraph text layers. Shape layer extents increase the size of the layer bounds as necessary. Paragraph text layers returns the bounds of the paragraph box. Note: After Effects 13.2 and later. Paragraph text extents added in After Effects 15.1. Example: myTextLayer.sourceRectAtTime().width Parameters t includeExtents Number Bool Type Array (4-dimensional) 22.4 Layer.effect(name) Description After Effects finds the effect by its name in the Effect Controls panel. The name can be the default name or a userdefined name. If multiple effects have the same name, the effect closest to the top of the Effect Controls panel is used. Example: effect("Fast Blur")("Blurriness") 86 Chapter 22. Layer Sub-objects After Effects Expression Reference, Release 0.0.3 Parameters name String Type Effect 22.5 Layer.effect(index) Description After Effects finds the effect by its index in the Effect Controls panel, starting at 1 and counting from the top. Parameters index Number Type Effect 22.6 Layer.mask(name) Description The name can be the default name or a user-defined name. If multiple masks have the same name, the first (topmost) mask is used. Example: mask("Mask 1") Parameters name String Type Mask 22.5. Layer.effect(index) 87 After Effects Expression Reference, Release 0.0.3 22.7 Layer.mask(index) Description After Effects finds the mask by its index in the Timeline panel, starting at 1 and counting from the top. Parameters index Number Type Mask 88 Chapter 22. Layer Sub-objects CHAPTER 23 Layer General 23.1 Layer.width Description Returns the width of the layer, in pixels. It is the same as source.width. Type Number 23.2 Layer.height Description Returns the height of the layer, in pixels. It is the same as source.height. Type Number 23.3 Layer.index Description Returns the index number of the layer in the composition. Type Number 89 After Effects Expression Reference, Release 0.0.3 23.4 Layer.parent Description Returns the parent Layer object of the layer, if it has one. Example: position[0] + parent.width Type Layer, Light, or Camera 23.5 Layer.hasParent Description Returns true if the layer has a parent or false if it doesn’t. Use the hasParent attribute to determine if a layer has a parent layer. You can use this attribute even if the layer has no parent layer at present. For example, the following expression indicates that the layer to which you apply it wiggles based on the position of the parent. If the layer has no parent, then it wiggles based on its own position. If the layer is given a parent later, then the behavior of the layer changes accordingly: idx = index; if (hasParent) { idx = parent.index; } thisComp.layer(idx).position.wiggle(5,20) Type Boolean 23.6 Layer.inPoint Description Returns the In point of the layer, in seconds. Note: In general, the value of outPoint is greater than the value of inPoint. However, if a layer is reversed in time, the value of inPoint is greater than the value of outPoint. Similarly, the value of startTime can be greater than the value of inPoint. Type Number 90 Chapter 23. Layer General After Effects Expression Reference, Release 0.0.3 23.7 Layer.outPoint Description Returns the Out point of the layer, in seconds. Type Number 23.8 Layer.startTime Description Returns the start time of the layer, in seconds. Type Number 23.9 Layer.hasVideo Description Returns true if the layer has video, or false if it doesn’t. Type Boolean 23.10 Layer.hasAudio Description Returns true if the layer has audio or false if it doesn’t. Type Boolean 23.7. Layer.outPoint 91 After Effects Expression Reference, Release 0.0.3 23.11 Layer.active Description Returns true if the Video switch is on for the layer and the current time is in the range from the In point of the layer to the Out point of the layer; false otherwise. Type Boolean 23.12 Layer.enabled Description Returns true if the Video switch is on for the layer; false otherwise. Type Boolean 23.13 Layer.audioActive Description Returns true if the Audio switch is on for the layer and the current time is in the range from the In point of the layer to the Out point of the layer; false otherwise. Type Boolean 23.14 Layer.sampleImage(point, postEffect=true, t=time) radius=[0.5, 0.5], Description Samples the color and alpha channel values of a layer and returns the average alpha-weighted value of the pixels within the specified distance of the point as an array: [red, green, blue, alpha]. If postEffect is true, the sampled values are for the layer after masks and effects on that layer have been rendered; if postEffect is false, the sampled values are for the layer before masks and effects have been rendered. The input value point is in layer space; the point [0, 0] is the center of the upper-left pixel in the layer. The input value radius specifies the horizontal and vertical distance from the sample center to the edges of the sampled rectangle. The default value samples one pixel. This example samples a rectangle 4 pixels wide and 3 pixels high, centered around a point 100 pixels down and to the right of the upper-left corner of the layer: 92 Chapter 23. Layer General After Effects Expression Reference, Release 0.0.3 thisComp.layer(1).sampleImage([100, 100], [2, 1.5]) Note: The postEffect parameter refers to effects applied directly to the layer, not to effects applied indirectly, such as with an adjustment layer. Note: Using sampleImage in an expression no longer disables multiprocessing. Note: Dan Ebberts provides an example of how to use the sampleImage method on his MotionScript website. Note: Todd Kopriva provides instructions for using the sampleImage method and the Point Control effect to monitor colors for a specified point during color correction on his After Effects Region of Interest blog. Parameters Argument type: point is an Array [2], radius is an Array [2], postEffect is a Boolean, and t is a Number. Type Array (4-dimensional) 23.14. Layer.sampleImage(point, radius=[0.5, 0.5], postEffect=true, t=time) 93 After Effects Expression Reference, Release 0.0.3 94 Chapter 23. Layer General CHAPTER 24 Layer Properties Description When you add masks, effects, paint, or text to a layer, After Effects adds new properties to the Timeline panel. There are too many of these properties to list here, so use the pick whip to learn the syntax for referring to them in your expressions. 24.1 Layer.anchorPoint Description Returns the anchor point value of the layer in the coordinate system of the layer (layer space). Type Array of Numbers (2- or 3-dimensional) 24.2 Layer.position Description Returns the position value of the layer, in world space if the layer has no parent. If the layer has a parent, it returns the position value of the layer in the coordinate system of the parent layer (in the layer space of the parent layer). Type Array of Numbers (2- or 3-dimensional) 95 After Effects Expression Reference, Release 0.0.3 24.3 Layer.scale Description Returns the scale value of the layer, expressed as a percentage. Type Array of Numbers (2- or 3-dimensional) 24.4 Layer.rotation Description Returns the rotation value of the layer in degrees. For a 3D layer, it returns the z rotation value in degrees. Type Number 24.5 Layer.opacity Description Returns the opacity value for the layer, expressed as a percentage. Type Number 24.6 Layer.audioLevels Description Returns the value of the Audio Levels property of the layer, in decibels. This value is a 2D value; the first value represents the left audio channel, and the second value represents the right. The value is not the amplitude of the audio track of the source material. Instead, it is the value of the Audio Levels property, which may be affected by keyframes. Type Array of Numbers (2-dimensional) 96 Chapter 24. Layer Properties After Effects Expression Reference, Release 0.0.3 24.7 Layer.timeRemap Description Returns the value of the Time Remap property, in seconds, if Time Remap is enabled. Type Number 24.8 Layer.marker.key(index) Description Returns the MarkerKey object of the layer marker with the specified index. Parameters index Number Type MarkerKey 24.9 Layer.marker.key(name) Description Returns the MarkerKey object of the layer marker with the specified name. The name value is the name of the marker, as typed in the comment field in the marker dialog box, for example, marker.key("ch1"). If more than one marker on the layer has the same name, this method returns the marker that occurs first in time (in layer time). The value for a marker key is a String, not a Number. This expression on a property ramps the value of the property from 0 to 100 between two markers identified by name: m1 = marker.key("Start").time; m2 = marker.key("End").time; linear(time, m1, m2, 0, 100); Parameters name String Type MarkerKey 24.7. Layer.timeRemap 97 After Effects Expression Reference, Release 0.0.3 24.10 Layer.marker.nearestKey(t) Description Returns the layer marker that is nearest in time to t. For example, this expression returns the time of the marker on the layer nearest to the time of 1 second: marker.nearestKey(1).time This expression returns the time of the marker on the layer nearest to the current time: marker.nearestKey(time).time Parameters t Number Type MarkerKey 24.11 Layer.marker.numKeys Description Returns the total number of markers on the layer. Type Number 24.12 Layer.name Description Returns the name of the layer. Type String 98 Chapter 24. Layer Properties CHAPTER 25 Layer Space Transforms Description Use layer space transform methods to transform values from one space to another, such as from layer space to world space. The from methods transform values from the named space (composition or world) to the layer space. The to methods transform values from the layer space to the named space (composition or world). Each transform method takes an optional argument to determine the time at which the transform is computed; however, you can almost always use the current (default) time. Use Vec transform methods when transforming a direction vector, such as the difference between two position values. Use the plain (non-Vec) transform methods when transforming a point, such as position. Composition (comp) and world space are the same for 2D layers. For 3D layers, however, composition space is relative to the active camera, and world space is independent of the camera. 25.1 toComp(point, t=time) Description Transforms a point from layer space to composition space. Parameters point t Array (2- or 3-dimensional) Number Type Array (2- or 3-dimensional) 99 After Effects Expression Reference, Release 0.0.3 25.2 fromComp(point, t=time) Description Transforms a point from composition space to layer space. The resulting point in a 3D layer may have a nonzero value even though it is in layer space. Example: fromComp(thisComp.layer(2).position) Parameters point t Array (2- or 3-dimensional) Number Type Array (2- or 3-dimensional) 25.3 toWorld(point, t=time) Description Transforms a point from layer space to view-independent world space. Example: toWorld.effect("Bulge")("Bulge Center") ..note:: Dan Ebberts provides an expression on his MotionScript website that uses the toWorld method to autoorient a layer along only one axis. This is useful, for example, for having characters turn from side to side to follow the camera while remaining upright. ..note:: Rich Young provides a set of expressions on his AE Portal website that use the toWorld method link a camera and light to a layer with the CC Sphere effect. Parameters point t Array (2- or 3-dimensional) Number Type Array (2- or 3-dimensional) 100 Chapter 25. Layer Space Transforms After Effects Expression Reference, Release 0.0.3 25.4 fromWorld(point, t=time) Description Transforms a point from world space to layer space. Example: fromWorld(thisComp.layer(2).position) See Expression example: Create a bulge between two layers for an example of how this method can be used. Parameters point t Array (2- or 3-dimensional) Number Type Array (2- or 3-dimensional) 25.5 toCompVec(vec, t=time) Description Transforms a vector from layer space to composition space. Example: toCompVec([1,0]) Parameters vec t Array (2- or 3-dimensional) Number Type Array (2- or 3-dimensional) 25.6 fromCompVec(vec, t=time) Description Transforms a vector from composition space to layer space. Example (2D layer): dir = sub(position, thisComp.layer(2).position); fromCompVec(dir) 25.4. fromWorld(point, t=time) 101 After Effects Expression Reference, Release 0.0.3 Parameters vec t Array (2- or 3-dimensional) Number Type Array (2- or 3-dimensional) 25.7 toWorldVec(vec, t=time) Description Transforms a vector from layer space to world space. Example: p1 = effect("Eye Bulge 1")("Bulge Center"); p2 = effect("Eye Bulge 2")("Bulge Center"); toWorld(sub(p1, p2)) Parameters vec t Array (2- or 3-dimensional) Number Type Array (2- or 3-dimensional) 25.8 fromWorldVec(vec, t=time) Description Transforms a vector from world space to layer space. Example: fromWorld(thisComp.layer(2).position) Parameters vec t Array (2- or 3-dimensional) Number Type Array (2- or 3-dimensional) 102 Chapter 25. Layer Space Transforms After Effects Expression Reference, Release 0.0.3 25.9 fromCompToSurface(point, t=time) Description Projects a point located in composition space to a point on the surface of the layer (zero z-value) at the location where it appears when viewed from the active camera. This method is useful for setting effect control points. Use with 3D layers only. Parameters point t Array (2- or 3-dimensional) Number Type Array (2-dimensional) 25.9. fromCompToSurface(point, t=time) 103 After Effects Expression Reference, Release 0.0.3 104 Chapter 25. Layer Space Transforms CHAPTER 26 Layer 3D 26.1 Layer.orientation Description Returns the 3D orientation value, in degrees, for a 3D layer. Type Array (3-dimensional) 26.2 Layer.rotationX Description Returns the x rotation value, in degrees, for a 3D layer. Type Number 26.3 Layer.rotationY Description Returns the y rotation value, in degrees, for a 3D layer. Type Number 105 After Effects Expression Reference, Release 0.0.3 26.4 Layer.rotationZ Description Returns the z rotation value, in degrees, for a 3D layer. Type Number 26.5 Layer.lightTransmission Description Returns the value of the Light Transmission property for a 3D layer. Type Number 26.6 Layer.castsShadows Description Returns a value of 1.0 if the layer casts shadows and 2 if the property is set to Only. Type Number 26.7 Layer.acceptsShadows Description Returns a value of 1 if the layer accepts shadows and 2 if the property is set to Only. Type Number 26.8 Layer.acceptsLights Description Returns a value of 1 if the layer accepts lights. Type Boolean Number 106 Chapter 26. Layer 3D After Effects Expression Reference, Release 0.0.3 26.9 Layer.ambient Description Returns the ambient component value as a percentage. Type Number 26.10 Layer.diffuse Description Returns the diffuse component value as a percentage. Type Number 26.11 Layer.specular Description Returns the specular component value as a percentage. Type Number 26.12 Layer.shininess Description Returns the shininess component value as a percentage. Type Number 26.13 Layer.metal Description Returns the metal component value as a percentage. Type Number 26.9. Layer.ambient 107
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