My current frames are nearing 50% plastic with the remainder some amalgam of JB weld, Epoxy, Shapelock, superglue and shrink tubing.  I broke the original hinges, and gluing to such a small surface yields very little strength.  Since then I have broken the hinges so many times I just didn't find it economical to buy new frames.  Thus, I am very interested in printing out new glasses frames over and over again; also, now that I have a CAD model of the glasses I can add room for wires and surface mount components and put neat things inside the glasses.  I also changed some of the dimensions of the glasses to help prevent them from falling off my head, my current frames have arms that are just a bit too short so they don't wrap around my ears much at all.To make them I taped my current frames to my screen zoomed to a 1:1 ratio, and carefully made a spline of the lens perimeter dimension, then did a bunch of fine tuning with my calipers and the dots consisting of the spline.  All the other splines were done visually to my taste,  as long as the lens dimensions are good the rest of the glasses can be any shape. I haven't printed these out yet, but when I do this is my plan.  I am going to use a hot air reflow station to heat up the nose bridge and lens areas, then bend them to the same curvature of my current frames by just holding the two parallel to each other.  I designed the frames to be just a little bit smaller than in real life to try and accommodate for the geometric stretching they will experience.  To make sure your lenses will fit in the frames print the image out at a 1:1 scale and cut out the interior of the frames, then insert the pieces of paper into your current frames and adjust accordingly.If your first pair doesn't ft the way you wanted, measure the improper dimensions, update your model, and reprint!I am including the CAD files so you can mess around with the lens holes for your own lenses if you like the frame design.  Also, the hinges just need 3mm pins, I figured I could just use filament with flattened ends if I can't print out a good pin.Detailed information here: http://umforum.ultimaker.com/index.php?/topic/3932-designing-a-new-set-of-glasses-frames/?p=57088