Some day before a trip my original prescription glasses frame broke, so I had to use 3D printing to save myself from being close to being blind during the trip. 

A quick outline in a sketch, a couple of Fusion 360 tricks, and we have a 3D printable glasses frame.

The frame is printed in PETG, as it's more flexible and less prone to breaking. Layer height of 0.2mm and printed solid (use more perimeters and top/bottom layers instead of 100% infill)

The legs can be slightly bent through heat and cooled with water for better comfort.

The legs are attached to the frame either with a 1.5mm steel rod, or a 1.5mm screw (don't overtighten)