I designed this accessory to cover the unused front derailleur mount on my mountain bike.  It's a simple, low cost alternative to the aluminum covers that are available and if you're really counting its a couple grams lighter as well. This cover can be attached to any bike with a direct/high mount front derailleur using a M6x10mm  flat head cap screw (available at any hardware store for about 5¢) I don't own a 3-d printer myself so I can't comment on the printer settings but the parts I had made were printed on end (starting at the "bottom" of the cover as viewed in the attached picture) using PLA. The cover in the picture was cleaned up using  240 grit sandpaper which gives it a professional looking matte finish.