I was recently asked to share how I did the kerf cutting on my Reuleaux box.
Disclaimer: the material I used were for Proofgrade basswood hardwood. Your settings will be different if you use any other material.
First, the engraves were set up in Illustrator to have three superimposed engraves, each slightly narrower than the previous one, like so:
In Illustrator you can create these lines by making the line stroke the desired thickness then doing an Outline Stroke operation.
Then, after uploading the design to Glowforge, I created a custom engrave setting which I used for all three engraves:
Okay, go to town!