Expressions and Tips

azerty AFX keyboard shortcuts

Loop animation before and after first and last keyframes

Should work with mask keyframes too, as opposed to loopOut/loopIn

Keep in mind that just like the normal loopOut, the last keyframe will always be replaced by the value of the first one, so you should have a sacrificial keyframe. Tried to have a one-liner but haven't wrapped my head around it quite fully

var offset = time<key(1).time?key(numKeys).time:key(1).time;
valueAtTime( (time - offset ) % ( key(numKeys).time - key(1).time ) + offset );

Display current layer name

screenshot tbd this is pretty specific

pct =' ░▒▓█';
startIndex = 1;//what layer do I start with ? or use thisComp.layer('Null 1').index;
lastCompIndex = thisComp.numLayers;
outputText = "";
for(i=startIndex+1;i<=lastCompIndex;i++){
	L = thisComp.layer(i);
	inP = L.inPoint;
	outP = L.outPoint;
	if(time >= inP && time < outP){
		curT = time - inP;
		maxT = outP - inP;
		per = curT/maxT;
		outputText += pct.substr(Math.floor(per*4),1) + ' ';  //comment out if you dont want visual progress
		outputText += L.source.name + '\n';
	}
}
outputText;

Simple one liner if you put a text object above each layer (you have to do the in/out yourself)

thisComp.layer(thisLayer.index+1).source.name

Spread items along a path

Change path to fit your need, apply expresson to the position of your item layer, duplicate and you're set

// pointonpath uses a range from 0..1 to grab a position so let's figure our where we are
// by counting the number of layers in the comp (and omitting a 'paths' layer at the bottom of the comp)

// [0,1] [0,.5,1] [0,.333...,.666...,1] [0,.25,.5,.75,1] etc
var percentpos = ( thisLayer.index - 1 ) / (thisComp.numLayers - 2)

// prevents a divide by 0 error if there is only one object halfway through the path
percentpos = isNaN(percentpos)? 0.5 : percentpos

//grab path layer and path ugh, 'path'
var pathLayer = thisComp.layer("path")
var path = pathLayer.content("Shape 2").content("Path 1").path

//grab position on path and use toComp to place it in the right spot
var pos = path.pointOnPath( percentpos )
pathLayer.toComp(pos)

Retime (varispeed) any value

Allows time remapping of animation without having to time remap (and precomp) using valueAtTime and a slider

Add a slider control that you call 'speed', and then add this expression to remap it according to the animation as seen in the video above

speed = effect("speed")("Slider");      //slider varies between 0 and 1, allows precise slow ups and downs in a single slider
p = thisProperty;                 
firstT = p.key(1).time;
lastT = p.key(p.numKeys).time;
p = p.valueAtTime(speed*(lastT-firstT)+firstT)

Padded timer text

t = effect("Slider Control")("Slider");
sign = (t<0)?'-':'';
t = Math.abs(t);

s = t%60;
m = Math.floor(t/60)%60;
h =  Math.floor(t/ (60*60));
s =  (s<10)?'0'+s:s;  		// pads
m = (m<10)?'0'+m:m;
sign+h+':'+m+':'+s;

Rand characters

chars = "GATC";
textValue = "";
for(i=0;i<100;i++){
	randVar = random() * chars.length;
	characterVar = chars.charAt(randVar);
	textValue = textValue + characterVar;
}
textValue;

Current Keyframe Index

//gobelins
a = timeRemap;
nk = a.nearestKey(time);
curframe = 0;
if(nk.time > time){
	curframe = nk.index-1;
}else{
	curframe = nk.index;
}
curframe*thisComp.frameDuration;

a = position;  //or whatever animated property
nk = a.nearestKey(time);

if(nk.time > time){
	nk.index-1;
}else{
	nk.index;
}

sample image pr les gobz

a = sampleImage([thisComp.width/2,thisComp.height/2], [thisComp.width/2,thisComp.height/2], postEffect = true, t = time);
a[0]+a[1]+a[2]+a[3];



////bake


v = effect("s")("Curseur")-effect("s")("Curseur").valueAtTime(time-1/25)==0?0:1

//////bake?

v = effect("hold")("Curseur");
a = 0;
for(i=0;i<=time*25;i++){
	if(v.valueAtTime(i/25)==1){
		a = i/25;
	}
}
a;

spread thingy

p = thisComp.layer("Null 1").transform.position;
delta = transform.position - p;
amplitude = thisComp.layer("Null 1").effect("amplitude")("Slider");
reach = thisComp.layer("Null 1").effect("reach")("Slider");
exponent = thisComp.layer("Null 1").effect("exponent")("Slider")

length = (length(delta));
if(length>0){
	transform.position += normalize( delta ) *  ( reach / Math.pow(length, exponent)  ) * amplitude;
}else{
	transform.position = [-2000,0]
}

Sprites

Duplicate layers by hand, add CtrlNul, offsetLeftRight, offsetDepth, spread sliders

//POSITION
seedRandom(index,true)
ctrl = thisComp.layer("CtrlNul");
dist = ctrl.effect("dist")("Slider");
offset = [ctrl.effect("offsetLeftRight")("Slider"),0,ctrl.effect("offsetDepth")("Slider")];

depthjitter = ctrl.effect("depthjitter")("Slider");
depthmult = ctrl.effect("depthmult")("Slider");
spread = ctrl.effect("spread")("Slider");

dist = dist+random()*spread;

transform.position+[(index%2)?-dist:dist,0,depthmult*index+depthjitter*random()]+offset



//ORIENTATION
lookAt(transform.position,thisComp.layer("Camera 1").transform.position)

Write on effect

fps = 1/thisComp.frameDuration;
cursorSpeed = 3;
text.sourceText.slice(0,time*fps)+((Math.floor(time*cursorSpeed)%2)?"|":" ");

Unscramble wip

wordspeed = time/1; //or a slider, or whatever
letterspeed = time*2;
txt = text.sourceText;
txtVar = "";
chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
splitxt = txt.split("\r");
maxLines = Math.min(splitxt.length-1, Math.floor(wordspeed));
for(i=0;i<=maxLines;i++){
	txtVar += (i>0)?splitxt[i-1]+"\r":"";
	len = splitxt[i].length;
	if(i == maxLines){
		for(j=0;j<=len-1;j++){
			txtVar += (j/len>=wordspeed-Math.floor(wordspeed))?chars.charAt(random()*chars.length):splitxt[i].charAt(j);
		}
	}
}
txtVar
;

Poor man's padding

//for lack of a cleaner version, up to 4 digits
a = time*25;
a=(a<10)?"000"+a:((a<100)?"00"+a:((a<1000)?"0"+a:a));

2d lookat

LookAt = "ball"
offset = 0
diffx = position[0] - this_comp.layer(LookAt).position[0];
diffy = position[1] - this_comp.layer(LookAt).position[1];
if (diffx == 0) {
diffx = 1 }
sign = 1 + (-1 * (diffx / Math.abs(diffx))) * 90;
radians_to_degrees(Math.atan(diffy/diffx)) + sign + offset

//with parenting
lookAt = "a";
L = thisComp.layer(lookAt);
p = L.toComp(L.anchorPoint);
d = thisLayer.toComp(anchorPoint) - p
d[0] = (d[0]==0)?1:d[0];
rotation + radians_to_degrees(Math.atan(d[1]/d[0])) - 90*d[0]/ Math.abs(d[0])

Pixilation (slow footage)

numImages = 15;
fps = 1/thisComp.frameDuration;
framesToWait = 3;Math.floor(time*fps/framesToWait%numImages)/fps;

Text scroller (DOS!)

//add your text, three slider control effects and rename them 'line width', 'line', 'line animation'
//then this expression on the source text
charlen = Math.ceil(Math.abs(Math. round(effect("line width")("Slider"),0))); //20
numlines = Math.ceil(Math.abs(Math. round(effect("lines")("Slider"),0))); //5
step = Math.ceil(Math.abs(Math. round(effect("line animation")("Slider"),0)));

txt = text.sourceText;
splitxt = txt.split("\r");
output = "";
for(i=step;i<numlines+step;i++){
	output += (i > splitxt.length - numlines)?".\r":splitxt[i].substring(0,charlen)+"\r";
}
output;

//single line
src = text.sourceText;
len = src.length;
scroll = time*25;
src.slice(scroll%len)+src.slice(0,scroll%len)

/////////////

charlen =200;
numlines = 15;
step = time/thisComp.frameDuration;
txt = text.sourceText;
splitxt = txt.split("\r");
output = "";
for(i=step;i<(step+numlines);i++){
	output += (splitxt.length<=i)?"\r":splitxt[i-1].substring(0,charlen)+"\r";          
}
output;

Open two simultaneous After Effects

"C:\Program Files\Adobe\Adobe After Effects CS5\Support Files\AfterFX.exe" -m

Command-Line

@echo off
"C:\Program Files\Adobe\Adobe After Effects CS5\Support Files\aerender.exe" -mp -project "W:\