There is some misinformation at the article - perhaps I mean "disinformation":
The legality of all this is unknown, not to say in dispute. It is legal to create your own firearms, but not to distribute them — and in the case of printed guns there's a bit of both going on. The ATF is looking at the subject, but for now it's all something of a grey area.There is no doubt that this is totally legal - the "distribution" is of information, which is protected under the First Amendment - pesky thing that it is - and the final result is only "illegal" to sell or "transfer" according to the BATFE under the yet-to-be declared un-Constitutional NFA and GCA laws.
Perhaps someone can come up with a method of embedding metal bracing in the printed parts...