So the ones in the store for $2 per pair of sunglasses are not the smart choice?
You want to download them to a 3d printer and print them up in a few hours after you go and purchase the lens?
After more thought it is obvious that the possibilities are too immense to have per-loaded items. Must be downloaded off internet.
An automotive or recreational vehicle bushing, o-ring, seal, or lens cap by themselves would amount to thousands of different applications.