Two diffusers made to fit on the Nikon SB-600 camera flash. One is closed and solid while another has an opening in the top.

Mostly round they have a soft effect like a vanity light. Highlights and reflections from the diffusers appear mostly circular and natural. You could cover the rectangular part where they fit on the flash with tape to make reflections even more circular.

I really like using the version with the opening in the top. It kind of does double duty as a diffuser and a snoot. I like the opening in the top not diminishing the flash power if I bounce the flash. If I point the flash directly at a subject the looks is kind of soft yet dramatic.

You want a brim to keep it on the print bed. The closed sphere version probably requires support.

These can be printed in vase mode for a very bright but fragile diffuser. It might have slight overhang issues near where the base and sphere intersect.

In vase mode (Special modes: Spiralize outer contour) I found telling cura the bottom layer is 22mm makes it print the flash attachment very solid then switch over to paper thin for the sphere part. Tell Cura the bottom layer is a whopping 44mm and you probably won't have any overhang problems.