I have a memory that around 10 years ago, Australia banned the very act of downloading and possessing 3-D files to make firearms. Theoretically, if your computer is seized and found to contain the SolidWorks files to make a Ruger, for example, you can be prosecuted. However I don't know that this was enacted into national law or later struck down.

A man in Queensland was given a suspended sentence for printing parts of a gun that did not together constitute a usable gun without some additional pieces[1].

Apparently there have been efforts there to ban 3-D printing of guns but so far they have not been successful.

In the U.S., while it is physically possible to do anything within the privacy of one's home, it is technically illegal to print a gun if you are not legally permitted to possess one.[2]

There are also existing laws on the books against plastic/undetectable guns which presumably would apply as well to resin/PETG/PLA printed firearms that have few or zero metal parts. Actually, one wonders why there haven't been more incidents of plastic guns smuggled onto aircraft in recent years, perhaps because K9 teams of bomb sniffing hounds are randomly used to detect bomb-making ingredients while standing in line at security. They are trained presumably to smell gunpowder as well as other chemicals. Leave your "Gunpowder Solid Men's Cologne" at home.

1. http://www.australasianscience.com.au/article/science-and-te...

2. https://thefederalistpapers.org/us/legal-3d-gun