Originally Posted by
Rare White Ape
It's not just 3D models. Places like Etsy are absolutely loaded to the gunwales with amateurish handmade crap that exists in copyright limbo, which I am surprised hasn't been looked at too deeply yet.
But beware of a big difference between Napster and Thingiverse and their ilk:
Napster users were sharing files that were created by someone else, then ripped into a lossy format, then shared freely, with no compensation to the original creator.
Thingiverse is different because the 3D files are an original creation of the uploader, they just take inspiration from ideas and designs that someone else owns the rights to.
I mention this because you want to create the "iTunes for 3D models" but the original objects do not exist in the first place like it does for music files that were copied wholesale. But that's not impossible to fix. When this gets off the ground and you build your audience, you'll be able to approach rights holders and licence the designs for people to print at home. I'm sure you've already thought of that, tho!
Imagine an app on your phone where you can customise a 3D model of your favourite Star Wars character; Vader's head on a Stormtrooper body, with Gungan legs or something, paint it all pink and send it over the network to the printer and BOOM out it pops. The kids would love it.