I see copyright infringement being the only regulated or illegal activity. The whole "YOU WOULDN'T DOWNLOAD A CAR?" thing is becoming more real. No, we won't be able to print a car anytime soon or anything that complicated for a long long time, but what if you're printing designer silverware? Or some Sam Adams beer glasses? Or some other plastic parts that are for specific products, like the batter compartment cover for my remote that keeps breaking? The piratebay already has a section for "3D blueprints", so they are already working towards that type of activity. I see 3D printers no more of an inherit threat than DVD/CD burners, but the details will be in what you are printing and whether or not that's someone elses product you're duplicating at home. We get into the same argument as we did with movies/music/tv/media/etc... just because you can duplicate it at home and "aren't actually stealing a physical product", and are only "making a copy", doesn't mean that people aren't still taking intellectual property that someone else spent a lot of time on, and doesn't mean there are not losses with things like this. All the printer/burner/downloader is doing is bipassing the manufacturing process, which is only a small part of most intellectual property, and research, and engineering that goes into a product. So, I guess I just see more of the status quo as far as the intellectual property battles go, and it will just bring that more into the spotlight than ever before. It will be interesting to say the least once 3D printing takes on more widespread adoption.
I thought about that, but there really aren't many illegal items in most countries. Other than certain types of guns. Chemically printing drugs is probably a ways off.
3d printed cars aren't all that far off. It's just the body, and probably will be for some time because processes for 3d printing metal aren't ready for prime time (and using a mill or lathe makes more sense for many parts anyway), but 3d printing a body and buying off the shelf parts for what can't be printed is close enough to downloading a car. I don't think printers large enough to do it are practical for home use just because they're so big, but it's not much of a stretch to imagine going to a service bureau to do it, like you would go to Kinkos/a printer if you needed large format prints.