This is the first part I've ever designed for 3D printing. These small hooks snap in place on 10 series 8020 and can be used to hang stuff from. I've printed about 20 of them and have used them in my van without issue. I printed these using a 3D printing service, so don't have information about machine settings.

I used the 8020 CAD design files that can be found here:

https://8020.net/downloads/index/designfiles

I designed the hook around them and printed my first revision which fell out. :) Then I made a few adjustments and printed again and they work great.