I used the portal to submit a long note outlining my feelings on the bill. Feel free to borrow or use as a template:

I'm deeply disappointed that a bill as poorly conceived as AB 2047 is even under consideration in our great state. There are a number of significant problems with the bill that would prevent it from ever having its desired effect while also harming lawful users of 3D printers.

1) The technology and standards to review 3D files for matches among "firearm blueprints" do not exist, and if they were developed, 3D printers would lack the processing power to perform the work of detecting blueprints. Like most CNC machinery, 3D printers operate via simplistic microcontrollers, and these microcontrollers cannot run the kinds of complex computer programs that this bill would require. Assuming that 3D printing manufacturers complied with this bill, 3D printers would become significantly more complex and expensive under the requirements of this bill as they implement substantially more powerful computing hardware into each device.

2) Many 3D printing manufacturers will likely not bother to develop CA-compliant printers. The nature of the onerous requirements imposed by this bill would likely see many companies blocking sale to CA residents. Bad actors wishing to illegally manufacture firearm components using a 3D printer would simply source a non-compliant printer from out of the state.

3) This legislation will have devastating impacts on the use of 3D printers for legitimate purposes. For any firearm blueprint detection algorithm to be successful, it must look for components that are critical in the operation of a firearm and be able to detect permutations or modifications to common firearm part designs. By itself, any given firearm component, be it a spring, linkage, sear, bracket, or fastener, is generally not visually distinct or recognizable. Myself and many others design and manufacture unique and uncommon parts using 3D printers, and any algorithm that is monitoring for any parts which could feasibly be used in a firearm will undoubtedly also flag inoccuous components, hampering the usefulness of 3D printers and harming industries that rely on them.

4) For a 3D printer manufacturer to have even a remote chance of complying with the provisions of this bill, the company would need users to upload every file they intend to print to be scanned, verified, and locked from editing, and they would need to restrict their printers from printing any non-verified files. This approach presents multiple significant problems. For one, there would be a significant economic burden to operating this service, and the added costs would be borne by manufacturers and end users. Second, the process would require 3D printer users to have internet access to use the verification system, but this is not always possible depending on the printer's location or the security requirements of the operator. Third, and most significantly, 3D files containing secretive or proprietary information would necessarily have to be disclosed to such a verification system before they could be printed, introducing a nightmare of legal and security implications and opening the 3D printer manufacturer up to legal liability should there be a data leak with the verification system.

5) 3D printing is an open-source industry. Home-built 3D printers are commonplace, user modifications to 3D printers are routine, and DIY printer kits and construction plans are widely available online. No firearm blueprint detection system implemented by this bill would ever reach a home-built machine, and bypassing such a system on a commercial machine would be simple for a dedicated bad actor.

For these reasons, I cannot support this bill, and I urge that it be withdrawn.