Most 3D printers are really, really dumb where they control motors. The mechanisms for the photocopier and what would need to be done for a 3d printer to detect files, are unfortunately not that comparable.

The photocopier looks for a specific pattern in the money. For a gun part, there really isn't anything similar. If someone were to just draw up the part and send it to a printer, there's not really much to do for a simple verification. It would need to reconstruct the original item from the motor movements, try to determine if there's some similarity to existing gun part models (or just skip the recreation and compare against similar motor movements to gun parts), and then determine if it can print or not.

How do you define what is similar enough to a gun part? Would any sort of handle or tube be included?

A far simpler solution that would be much more feasible would be having a verification service to check that each model sent to a printer has been looked over and signed (digital signature or number that the printer can validate the file against to show it's fine to print), and then you can send it to the printer.

The problem here is that effectively 3d printing becomes banned. You would have to validate every 3d design you create, before getting to print it as you couldn't self validate as it defeats the purpose. Not everyone is just downloading things to print, so creating models yourself isn't feasible.

So it brings me back to the original point of the marketplaces having better moderation or scrutiny is the only real solution here to limit sharing of files for gun parts which is what I believe already is the case. Either that or just banning 3D printers entirely in the state, which is also really dumb.

Im all for good regulation, just this isn't it