This is a diffuser for the Godox TT685 II. It has the option to slot in a Grid.

You should print it with transparent white filament. The main body needs supports for the grid slot.

For the Grid use the modify_diffuser, set bottom and top layers to 0 and adjust the infill amount and pattern for your Grid. I used 9% honeycomb infill. I also printed it with a 0.8mm nozzle to get a thicker infill lines.