When the glass diffuser on our kitchen ceiling light fixture inexplicably fell onto the floor and shattered, we thought we could just go to Home Depot and buy a new one. Turns out they only sell the complete fixtures. So, we designed a built our own custom one, which actually looks much nicer than the old one. This is for a 10" nominal diameter ceiling light fixture, but of course is easily modified for other sizes. We used translucent PLA, however any translucent material could be used such as Taulman T-Glase or Taulman 645. You will obviously need adequate build volume, and a heated bed helps prevent curling.