Create a headless script with Duik

Using the Duik API, it is very easy to create simple headless scripts, which don’t use any user interface, to automate your workflow, or to assign keyboard shortcuts to Duik features or your own automations for example.

Create the file

Let’s assume you’ve already downloaded the API, and saved it in the same folder where you’re creating your headless script.

Now, create a new text file with any text editor¹, and name it using the .jsx extension, which is the usual extension for After Effects scripts. In this example, we’re creating a script which will automatically parent all selected layers to the one selected at last, let’s call it Auto-Parent.jsx.

First, we’re going to add what’s is called an anonymous function. It’s a standard function, but without any name. All the script will be written inside this function; this is a simple way to make sure everything stays contained and nothing leaks to the global space, which could break other scripts.

This is how the script looks like with just this anonymous function:

(function(){

})();

The first line creates the function, the last line closes and executes it. We’re going to write the script in between.

Include the API

The first thing to do is to include the API with:

    #include "DuAEF_Duik_api.jsxinc"

Note that this will work only if the API is located next to the script, in the same folder. If not, you can use a path² to the API instead of only the name.

After the inclusion, we need to call the DuAEF.init function to prepare everything.

    DuAEF.init( "Auto-Parent", "1.0.0", "Your (company) Name" );

The three arguments are:

• A name for the script
• The version of the script
• Your name or the name of your company

The code to run

Now that everything is ready, we can write the actual code. If this wasn’t a headless script, we would start by writing the User Interface, and then show it to the user.

As it’s not the case, we just need to tell the API we’re going to run without UI.

    DuAEF.enterRunTime();

And now, let’s do something!

Our goal is to create a script which will parent all selected layers to the one which was selected last. Duik can do that for us, it’s the autoParent function!

As Duik comes with many features, they’re sorted in namespaces, which actually correspond to the panels of Duik. The Auto-Parent method is located in the Constraint panel and namespace.

    Duik.Constraint.autoParent();

And that’s all! We’ve finished the script.

Note that the autoParent function can take one argument, to tell it to parent only orphans (i.e. the layers which do not have any parent yet). If that’s what you want you could write Duik.Constraint.autoParent(true); instead.

Almost all features of Duik are available as very simple functions in the API.

The complete script

This is the finished script, with some comments³ to help you learn and understand.

// First, create an anonymous function.
// This is very important to make sure we don't leak anything
// to the global space and won't break anything by mistake.
(function(){

    // Here we include the Duik API
    #include "DuAEF_Duik_api.jsxinc"

    // Running the init() method of DuAEF is required to setup everything properly.
    DuAEF.init( "Auto-Parent", "1.0.0", "RxLaboratory" );

    // There's no User Interface, which would have to be built here.
    // Let's go right to the execution.

    // This method has to be run once before any other method from the API.
    DuAEF.enterRunTime();

    // Run the Auto-Parent method
    // See: http://duik.rxlab.io/Duik.Constraint.html#.autoParent
    Duik.Constraint.autoParent();

// Close the anonymous function.
})();

You can now use this script to assign a keyboard shortcut for parenting layers.