Two types of diffusers to fit onto the Canon Speedlight 580EX II flash. I made these for our photographer at MAKE and they've been holding up even after several weeks of daily use.
The triangular version maximizes surface area for greater light diffusion.
The rectangular version is smaller but can be slid down the flash to make it compact and portable.
Both have a tight slide fit that allows the diffuser to be adjusted up or down the flash.
Autodesk Inventor file included.
For the rectangular version, the attached Cura profile have good settings to start with.
For the triangular version, change to have zero bottom layers and zero infill.
I suggest 0.1 to 0.2 mm layer resolution, single wall/shell/parameter, and using the Joris setting in Cura. The Joris setting makes the wall as a single continuous spiral, resulting in a very strong part.
Note: The triangular version might form a slit at the very top since it is rounded, making the top only one or two layers of solid infill (depending on your layer thickness). Flash performance is still great/not affected by it though.
I used 2-year-old MakerBot clear PLA on an Ultimaker to print these.