My first design using Sketchup. Led strip mount and diffuser. I made a small and an extended version.

Extended version needed to be printed on 45 degree angle for my Wanhao Duplicator i3 Printer. May be the same for you. Use any infill you like, obviously the less you use the more light you will let through.

Changes could be made, as this is first thing I have made, hope it helps someone out too.