Common AE Expressions

Inertial Bounce is like making your moves "rubbery." Layers will overextend, then settle into place on position and rotation keyframes.

// Inertial Bounce (moves settle into place after bouncing around a little)
n = 0;
if (numKeys > 0){
n = nearestKey(time).index;
if (key(n).time > time){
n--;
}
}
if (n == 0){
t = 0;
}else{
t = time - key(n).time;
}

if (n > 0){
v = velocityAtTime(key(n).time - thisComp.frameDuration/10);
amp = .05;
freq = 4.0;
decay = 2.0;
value + v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);
}else{
value;
}

//Takes 3d space of layer and converts to 2d screen space

thisComp.layer("Light 1").toComp([0,0,0]);

Jumpy Wiggle 1 makes wiggle skip and hold rather than move fluidly.

// Jumpy Wiggle 1 (moves at a random FPS)
v=wiggle(5,50);
if(v < 50)v=0;
if(v > 50)v=100;
v

Jumpy Wiggle 2 is similar to 1, but works at a defined FPS so your "jump" will happen at a regular pace.

// Jumpy Wiggle 2 (moves at a defined FPS)
fps=5; //frequency
amount=50; //amplitude
wiggle(fps,amount,octaves = 1, amp_mult = 0.5,(Math.round(time*fps))/fps);

Sometimes you just want something to move constantly without keyframing it. Use throw.

// Throw (move at a constant speed without keyframes)
veloc = -10; //horizontal velocity (pixels per second)
x = position[0] + (time - inPoint) *veloc;
y = position[1];
[x,y]

Same as throw, but for rotation.

// Spin (rotate at a constant speed without keyframes)
veloc = 360; //rotational velocity (degrees per second)
r = rotation + (time - inPoint) *veloc;
[r]

//Autofade: Add to opacity

transition = 20;       // transition time in frames
if (marker.numKeys<2 br=""> tSecs = transition / ( 1 / thisComp.frameDuration); // convert to seconds
linear(time, inPoint, inPoint + tSecs, 0, 100) - linear(time, outPoint - tSecs, outPoint, 0, 100)
}else{
linear(time, inPoint, marker.key(1).time, 0, 100) - linear(time, marker.key(2).time, outPoint, 0, 100)
}

//Snap zoom in and out: apply to scale
snapScale = 300; //percent of scale to zoom

trans = 4; //  transition time in frames
trans = trans * thisComp.frameDuration;
inTrans  = easeOut(time, inPoint, inPoint + trans, [snapScale,snapScale], [0,0]);
outTrans = easeIn(time, outPoint, outPoint - trans, [0,0], [snapScale, snapScale]);
value+ inTrans + outTrans

// Y Axis Jitter
probability = 8 ;  //higher is less likely
pos = 50;

val  = random(-probability-2, 1);
m = clamp(val, 0, 1);
y = wiggle(10, pos*m)-position;
value + [0, y[1]]

3D layer invisible while facing backwards to camera (use on Opacity):

if (toCompVec([0, 0, 1])[2] > 0 ) value else 0

Parent Puppet pin to Null (there is a script on AEscripts for this also I beleve, haven't used it):

n=thisComp.layer("NullObject_Name");

nullpos=n.toComp(n.anchorPoint);

fromComp(nullpos);

Numbers:

Add a slider and name to 'Value'

places = 3; //number of decimal places desired

val = effect("Value")("Slider"); //sub in the name of your slider here

factor = Math.pow(0.1, places) ;

sign = "";

if (val < 0) sign = "-";

val = Math.abs(val);

whole = Math.floor(val);

fraction = "" + Math.round((val - whole)/factor)*factor;

for (fraction; fraction.length < places+2; fraction+="0");

sign + whole + "." + fraction.substring(2, places+2)

Position from layer above

thisComp.layer(index - 1).transform.position

Number of decimal places

//--Begin Expression

nums = thisComp.layer("Deep Lime Green Solid 1").effect("Slider Control")("Slider");

numOfPlaces = 3;

//--Do not modify below this line

function roundTo(number, places)

{

num = Math.round ( Math.pow(number, places) );

NUMBER ROUNDING

myNumber = 23.3453255243697978;

round(myNumber, 2);

function round(aNum, dP) {

     return(Math.round(aNum*Math.pow(10, dP))/Math.pow(10, dP));

}

num /= Math.pow(10, places);

return num;

}

roundTo(nums, numOfPlaces)

//--End expression

Round decimal

Math.round(your_decimal_number_here)

RANDOM MOVEMENT

//Returns two values by default; [x-pos. y-pos]

segDur = .5;// duration of each "segment" of random motion

minVal = [0.1*thisComp.width, 0.1*thisComp.height];

maxVal = [0.9*thisComp.width, 0.9*thisComp.height];

seed = Math.floor(time/segDur);

segStart = seed*segDur;

seedRandom(seed,true);

startVal =  random(minVal,maxVal);

seedRandom(seed+1,true);

endVal = random(minVal,maxVal);

ease(time,segStart,segStart + segDur, startVal, endVal);

Time Output

//Contains rounding + always display 2 digits

min = Math.floor(time);

strMin = String(min);

if(min < 10){

  strMin = '0' + strMin;

}

sec = Math.round(((time) - min)*100);

strSec = String(sec);

if(sec < 10){

  strSec = '0' + strSec;

}

"18:22:" + strMin + ":" + strSec

Random Letters

//Begin expression

numOfLetters = 25; //Modify me

useSpaces = true; //Modify me

changeEveryFrame = true; //Modify me

//Don't modify below this line

seedRandom(index, !changeEveryFrame)

//--

function genLetter( ) {

r = random(65, 90);//from a to z

return String.fromCharCode( r );

}

s = "";

for(i = 0; i < numOfLetters; i++)

{

s += genLetter();

if(useSpaces)

s += " ";

}

s

//End expression

Loop

//Looping Script

freq = 0.6;

amp = 5;

loopTime = 10;

t = time % loopTime;

wiggle1 = wiggle(freq, amp, 1, 0.5, t);

wiggle2 = wiggle(freq, amp, 1, 0.5, t - loopTime);

linear(t, 0, loopTime, wiggle1, wiggle2)

Random Position HOLD

holdTime = .5; //time to hold each position (seconds)

minVal = [0.1*thisComp.width, 0.1*thisComp.height];

maxVal = [0.9*thisComp.width, 0.9*thisComp.height];

seed = Math.floor(time/holdTime);

seedRandom(seed,true);

random(minVal,maxVal)

Smooth Keyframes

smooth(width = .2, samples = 5, t = time)

Creating Trails

http://www.motionscript.com/mastering-expressions/follow-the-leader.html

delay = 5; //number of frames to delay

d = delay*thisComp.frameDuration*(index - 1);

thisComp.layer(1).position.valueAtTime(time - d)

OR

thisComp.layer(index+1).transform.position.valueAtTime(time-.1)

Smooth Wiggle

http://forums.adobe.com/message/1799293#1799293

seedRandom(time*5);

wiggle(0,100);

Copy size and rescale from layer above

thisComp.layer(index - 1).scale-[7,7]

Copy rotation from layer below and rotate 22.5

thisComp.layer(index+1).transform.rotation+22.5

Copy position from layer above

thisComp.layer(index-1).position

Keep x at 960, move Y X time * 100 pixels

[960, position[1]+time*-100]

Time delay from layer above

thisComp.layer(index+1).transform.position.valueAtTime(time-.1)

Wiggle in one direction only

Wiggle Y Only:

[value[0],wiggle(1,100)[1]]

Wiggle X Only:

[wiggle(5,30)[0],value[1]]

Wiggle X and Y seperately:

[wiggle(5,30)[0],wiggle(1,100)[1]]

Loop Types

loopOut("pingpong")  // ABCD(CBABCDCBA)

loopOut("continue") // ABCD(EFGHIJKL)

loopOut("Cycle")  // ABCD(ABCDABCD)

Range Mapping

input = effect("Slider Control")("Slider");

inputLow = 0;

inputHigh = 100;

outputLow = -100;

outputHigh = 100;

linear(input,inputLow,inputHigh,outputLow,outputHigh)

For when you want burn in text to automatically display the layer name (i.e. render out tiff sequence first, then making a QT w/ name burn in).

Make text layer, add expression to 'source text'.

function pad(number, length) { var str = '' + number; while (str.length < length) { str = '0' + str; } return str; } var theLayerName = thisComp.layer(index+1).name; var theLayerNameSplit = theLayerName.split('.'); theLayerNameSplit[0];

To change which layer is read for the name, change the (index+1) to (index+2) and so on.

Counting numbers with comma:

startCount = 0;

endCount = 11689;

countDur = 1.2;

s = "" + Math.round(linear(time,0,countDur,startCount,endCount));

if (s.length > 3){

s.substr(0, s.length -3) + "," + s.substr(-3);

}else{

s

}