AE Script – Move Selected Layer Group

Sometimes you want to select a group of layers in After Effects, and just move them all to the current time indicator and keep their relative timing. So you think ”I’ll just hit [ and move them all!” Only then you’re immediately hitting undo as you notice all the layers in-points moved to the CTI, erasing your carefully crafted timing. I got tired of that a long time ago and wrote a little script for my ft-toolbar setup. The topic recently came up on Twitter so I thought I’d share it.

Download below and set to an ft-toolbar button, or set a keyboard shortcut on macOS. Open up System Preferences: Keyboard: Shortcuts. Then click on App Shortcuts and add After Effects. Then you can type in ‘MoveSelectedLayerGroup.jsx’ and assign a shortcut.

Expression: oscillate()

There’s many occasions I just need a certain parameter in After Effects to go between two values. There’s several ways to do this (including keyframing), but one of the go-to methods is using the Math.sin() expression to get a nice sine wave. But for whatever reason, I always end up reminding myself the correct way to write out Math.sin( Math.PI * 2 * time * frequency ) * amplitude in my expression. I also wanted a bit more options. Sure cosine is easy (Math.cos()) but what about a triangle wave? Or Sawtooth?

So I wrote up a function to paste into an expression to give me many options. The image above shows some example usage, but here’s the complete rundown…

oscillate("wave-type", frequency, amplitude, time)


A string or integer defining the type of wave to produce. Why the option to use numbers? Maybe you want to use some other code to determine the type of wave. Using a number just makes that easier. In general use, the strings are just easier to remember.

  • "sin" or "sine" or 1 (default)
  • "cos" or "cosine" or 2
  • "square" or 3
  • "saw" or "sawtooth" or 4
  • "tri" or "triangle" or 5


Number of full waves per second. Defaults to 1.


The height of the wave above or below 0. Defaults to 1.


The value to drive the wave. Defaults to time, but it could also use any other variable. Consider using the layer’s x position to drive the function on its y position.


All the parameters are optional in the function. Using just oscillate() will give you a sine wave with a frequency and amplitude of 1 over time. Or fill in all the parameters to get exactly what you want. However, the parameters must be given in order. So if you just want to change the amplitude, you’ll need to include the wave-type and frequency before it.

The Code

And finally, here’s the code. Paste this into your expression (usually at the end), and you can call oscillate() to get a nice oscillation.

oscillate(wave-type, frequency, amplitude, time)

Returns value along time axis of different wave types or false if error.
All arguments are optional. Function defaults to Sine wave over time with frequency and amplitude of 1.
function oscillate(w,f,a,t) {
    if(!arguments[0]) w="sin";
    if(!arguments[1]) f=1;
    if(!arguments[2]) a=1;
    if(!arguments[3]) t=time;

    try {

            case "1": case "sin": case "sine":
                return Math.sin(2*Math.PI*x)*a;
            case "2": case "cos": case "cosine":
                return Math.cos(2*Math.PI*x)*a;
            case "3": case "square":
                return Math.floor(Math.sin(2*Math.PI*x))*a*2+a;
            case "4": case "saw": case "sawtooth":
                return ((x%f)/f)*a*2+adj;
            case "5": case "tri": case "triangle":
                return (Math.abs(((x%f)/f)*a*2+adj)-a/2)*2;
                return false;
    } catch(e) {return false}

After Effects: A Better Bounce

A lot of bounce expressions rely on either setting parameters like frequency and decay, leading to guess work for when bounces will end or how long they’ll last. Or the expression will settle the bounce on the last keyframe, giving you no real idea how fast the object will move before the bounce. This always bothered me.

Then this week on the Motion Design Slack group, someone was asking about getting bounce expressions to behave more intuitively. So I rolled up my sleeve and got to modifying an existing expression for inertial bounce (actually elastic). Here’s the resulting code:

bounces    = 4;     //total number of bounces
duration   = .25;   //duration of each bounce in seconds
amp        = .05;   //multiplier for incoming velocity used in bounce
decay      = 3;     //exponential decay of bounce height

mult = (bounces-Math.floor(t*freq))/bounces;
if (n>0 && mult>0) {
    v=velocityAtTime(key(n).time-0.001)*amp; //velocity to use
    b=Math.abs(Math.sin(freq*t*Math.PI))*Math.pow(mult,decay); //bounce calculation
} else {value;}

Now this won’t be physically accurate. Each resulting bounce would really be shorter in time as well. If that’s what you’re looking for, Dan Eberts has a physically accurate expression. And there’s many other bounce tools like After Ease, Ease and Wizz, and Duik. However, this will give you a specific number of bounces, a set time for each bounce, and take incoming speed from keyframes for the object. This works great as an ft-toolbar button or a Text Expander snippet.

Interlacing: A Twitter Conversation

It all started with this tweet:

the sooner interlaced video dies a horrible death, the better.less than a minute ago via web

Once I retweeted that, it elicited the following response:

@dan_hin @conigs |W|h|a|t|s w|r|o|n|g w|i|t|h i|n|t|e|r|l|a|c|i|n|g|?|less than a minute ago via Twitter for Mac

@vonherwig @dan_hin |h|W|t|a|w s|o|r|g|n i|w|h|t n|i|e|t|l|r|c|a|n|i|?|g| #WrongFieldOrderless than a minute ago via Echofon

@conigs @dan_hin Looks fine on my Trinitron. *shrugs*less than a minute ago via Twitter for Mac

Something New…


If you’re a motion designer, you’ll be interested in something new I’m helping with. A few of us are starting something called The Motion League. More details will come in the next couple weeks.

How to Install Final Cut Studio 3

Yesterday, Apple quietly announced the new Final Cut Studio. The “what’s new” page actually has some nice features, though many I’ve talked to are surprised this is a full point upgrade to Final Cut Pro (myself included). There’s already comprehensive posts covering the new features and what they could mean. I really don’t have much to add.

Today, however, I am posting perhaps the most important link: How to Install Final Cut Studio 3. This is spot on from my own experience and a very comprehensive guide.

[via @editblog]

Marketing BS & Unwanted “Features”

Speaking of the Philips Cinema 21:9, Scott Simmons of Editblog fame has a post concerning, to put it bluntly, the bullshit of “picture enhancing features” on new TVs, specifically, Philps.  This sums up his feelings (and mine):

I call marketing bullshit on this TV.

I couldn’t have said it better. And I won’t. Go read Scott’s take on features like Ambilight, “Perfect Natural Motion,” and “distortion free” picture resizing. The general consensus is that none of it adds to the viewing experience in a positive way.