A Script for Better Rounded Corners in Illustrator


If you’re like me you might not have given much thought to the appearance of rounded corners in Illustrator. They’re easy enough to create and modify. And they do their one job: they are round. But like some things that seem fine at a glance, Illustrator’s rounded corners reveal their imperfections on close scrutiny.

The problem is the point where a straight side meets the curve, which is a perfect segment of a circle. It’s abrupt change; not an elegant visual transition.

rounded corners in Illustrator

I have to admit I was never really bothered by this until I learned of the existence of a script written by Sergey Nikolaev to make smoother rounded corners, and read his accompanying blog post.

It reminded me of this xkcd comic about kerning.

kerning comic

Now that I know the joys of the squircle, and why Apple uses them for the shapes of icons in iOS, there’s no going back. Regular rounded corners in Illustrator look bad to me now.

You can download the script and read all the documentation and detailed installation instructions at GitHub.

When you run the script you get a dialog where you can decide how much to move the anchor points and handles that give the corners their shape. There’s also a Preset menu where you can save your favorite settings to reapply them quickly.

Illustrator rounded corners script dialog

Here’s a comparison of Illustrator’s native rounded corners to ones modified by the script. You can see that the anchor points have been moved away from the corners and the handles have been lengthened to give a smoother overall appearance.

a comparison of regular rounded corners in Illustrator to a squircle

By the way, Astute Graphics also offers the ability to make squircles in the the Dynamic Corners panel, which is part of their VectorScribe plug-in. You can watch a demo of it in this YouTube video.

So, if you want to become a squircle snob like me, grab the script or the plug-in, and start producing smoother rounded corners in Illustrator.

Editor in Chief of CreativePro. Instructor at LinkedIn Learning with courses on InDesign, Illustrator, Photoshop, GIMP, Inkscape, and Affinity Publisher.
  • Alain GB says:

    Magnifique, merci pour la découverte, un portage vers InDesign serait-il possible ?
    Wonderful, thank you for the discovery, would a port to InDesign be possible?

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