I will soon be pulling this off of Thingiverse, in protest of Makerbot's closed sources. You can find it at Cubehero: https://tinyurl.com/pt3t4fb

A semi-parametric aperture that I drew in SolidWorks to practice modeling. Based off of, but not copying from, several other irising boxes. As I don't have access to a (FFF) 3D printer, I have not tested it, but the assembly fits together and moves quite well. I left reasonable tolerance on every joint except for the sliding among leaves, which shouldn't be a problem. When the aperture is open, it does not leave an entirely empty circle in the middle -- I sacrificed that to make it look better as it opens.

Print one of each ring, five leaves, and five pins. Fit the leaves onto the base ring with the slots facing upward. Drop the top ring onto the base and leaves, lining the nubs up with the slots in the leaves. Place the pins in the holes in the columns on the base ring, using a drop of CA glue to secure them in place. Leaves may be able to snap on and off (Or they may break, I haven't tried it). Twist the rings to open and close the leaves.