The arm of my favorite sunglasses broke in two so I decided to make a replacement one. It is not exactly the same but it is fairly quick to print.
Each pair of sunglasses is a little different so this might not fit your glasses. It is not a real clean openscad design, but the location of the hinge pin is configurable.

These particular glasses use a metal screw with a very coarse thread to act as the hinge. You will probably have to print a few of these to adjust the parameters so that it fits with your glasses.

At the last minute I threw on my name to the side. Its always nice to customize something.

I printed in medium mode and used supports simply for the hinge gap, this is only about 3mmx2mm in size.
I printed the arm with the hinge hole pointing down and the letters on top, this way the curve of the arm could be printed without supports.

In close up you can see the lines of the printer, but at normal distance I think it looks pretty good!