NT Productions shows how you can recreate any shape layer using a script.

Shape layers are a feature in After Effects that is the backbone behind motion graphics workflows. They have a lot of features, and they have a lot of options too. In this new tutorial from Nathan Lovell you can learn how to recreate shape layers using a few lines of code. 

The tutorial covers a few different techniques and shows how to add custom contents to the shape like rounded corners and custom shapes with a stroke and a fill. Reverse engineering shape layers will allow you to build any kind of shape from scratch with just a few lines of code. Once you learn these techniques, you can easily apply them to recreate any shape layer, or for that matter, any property using a script.

Nathan shares a lot of scripting tutorials using extend script and other methods for After Effects. Check out some of those here.