Right on. The only problem with M-DISC is that it's industrial only and most certainly not free for public use. I know that isn't relevant to the question I as

Right on. The only problem with M-DISC is that it's industrial only and most certainly not free for public use. I know that isn't relevant to the question I asked, as stated, but the focus was on 3D printing because it is something any person could do, rather than something that has to be manufactured by specialized equipment.