3D Printing and Firearm Blocking Technology

On February 17, 2026, California introduced Assembly Bill 2047 which is known as the Firearm Printing Prevention Act. It would require several things to happen:

• On or before July 1, 2027, the Department of Justice must publish written guidance on performance standards for persons or entities engaged in the creation of firearm blueprint detection algorithm to be certified for use by 3-dimensional printer manufacturers, as specified.
• On or before January 1, 2028, the Department of Justice must accept applications for certification of firearms blueprint detection algorithms and begin issuing certifications of algorithms that meet or exceed the performance standards.
• On or before July 1, 2028, any business that produces or manufactures 3-dimensional printers for sale or transfer in California must submit to the Department of Justice an attestation for each make and model of printer they intend to make available for sale or transfer in California, confirming that the manufacturer has equipped that make and model with a certified firearm blueprint detection algorithm.
• On or before September 1, 2028, the Department of Justice must publish a list of all the makes and models of 3-dimensional printers whose manufacturers have submitted complete self-attestations and would require the department to update the list no less frequently than on a quarterly basis and to make the list available on the department’s internet website.
• On March 1, 2029, the bill would prohibit the sale or transfer of 3-dimensional printers that are not equipped with firearm blocking technology and that are not listed on the department’s list of manufacturers with a certificate of compliance verification.

The bill would authorize a civil action to be brought against a person who sells, offers to sell, or transfers a printer without the firearm blocking technology. It would also make it a crime to knowingly disable, deactivate, uninstall, or otherwise circumvent any firearm blocking technology.

The bill refers to a couple of terms which deserve exploration. According to Assembly Bill 2047, “firearm blocking technology” means hardware, firmware, or other integrated technological measures capable of ensuring a three-dimensional printer will not proceed to any print job unless the underlying three-dimensional printing file has been evaluated by a firearms blueprints detection algorithm and determined not to be a printing file that would produce a firearm or illegal firearm parts. The bill also states that “firearm blueprint detection algorithm” means a software service that evaluates three-dimensional printing files, whether in the form of stereolithography (STL) files or other computer-aided design files or geometric code, to determine if the files can be used to program a three-dimensional printer to produce a firearm or illegal firearm parts, and flag any such files to prevent their use to manufacture a firearm or illegal firearm parts.

I searched the web to try to find companies or individuals who have created such technologies or algorithms, and the search results mainly yielded articles and videos about the 3D printing legislation in Washington, New York, and California. I then asked ChatGPT to summarize what it knows about firearm detection technology, and it stated that Thingiverse uses AI to detect and remove gun design files, and there are experimental tools such as 3D GUN’T. However, the solutions seem to be immature. ChatGPT concludes that the firearm blueprint detection algorithms mentioned in legislation are “largely hypothetical or early-stage” and “reliable prevention at the printer level is an unsolved problem” which is consistent with my observations.

I think that AI approaches are the best way to address this need, but I can also think of many challenges to doing it accurately. First, 3D models are not always designed so that the finished physical object is contained in a single file—they are often provided in multiple parts. Splitting a model could be necessary because the object is too large to fit on a standard print bed. It could also be because different parts of a model need to be printed with different materials (e.g., to add strength or flexibility) or colors. It could also be that certain features of a model are best printed in a certain orientation to optimize strength, improve print bed adhesion, reduce the need for support material, or factors to minimize chances of print failure. The bottom line is that when models are split into multiple objects, it could become difficult for firearm blocking technology to accurately understand that many parts, when assembled, would resemble a firearm.

Second, firearms come in many shapes and sizes. I suppose that with enough training data, AI-based detection methods could learn what many different kinds of firearms look like. But what happens when users modify (or “remix” as the 3D modeling community would say) models so that they differ from training data? For example, what if a 3D model of a gun is presented in the form of a kit card? Its overall geometry would be a square or rectangle. When the borders and connectors of the kit card are snapped off, it would look like a gun, but that would happen in post-processing (downstream of the AI detection). Or what if a 3D model of a firearm was natively designed with support material? The support material could make the overall geometry significantly different than the firearm after all the support material was removed. Could firearm blocking technology be reliable enough to understand all of this?

Third, will firearm blocking technology be capable of understanding functional capabilities of 3D models? In other words, could it tell the difference between a “real” functional firearm and a non-functional prop? What if someone wants to print a replica of Han Solo’s blaster for a Halloween costume or a Star Wars convention? Would firearm blocking technology have a high enough false positive rate that it could become a burden to print legitimate models that pose no danger to society?

Perhaps there are current solutions to these challenges, or maybe technology will advance rapidly enough in the next couple years that these problems will be in the rear view mirror. In any case, I believe we have a major problem with guns in the United States, and I would love to see progress on reducing injury and death from firearms. However, it feels to me that the 3D printing legislation is misdirected, and I fear that it will adversely affect hobbyists like me while doing little to nothing to curb illegal activity because criminals will just find ways to circumvent firearm blocking technology.

For an additional perspective, read The Dangers of California’s Legislation to Censor 3D Printing by the Electronic Frontier Foundation.

Sending a Fax in 2026

The other day my wife gave me 4 pages of paper and asked me to take it to a store and fax it to its destination. I suspected that this was the most expensive and inconvenient method to send the document. Based on various online sources, sending a domestic outgoing fax at FedEx costs approximately $2.50 for the first page, followed by approximately $2.00 for each additional page, so a 4-page fax would cost approximately $8.50. Prices would be similar at The UPS Store, Staples, Office Depot, and other similar offerings and of course would vary from store to store.

Therefore, I asked her to consider alternative options. Could the document be sent as a PDF file via email? She told me that email was unfortunately not an option and that it had to be sent via fax.

I read online that some public libraries offer free or low-cost fax services. I checked the website for our local library, and unfortunately it did not list faxing as a service at that branch. I wanted to call the library to ask if they offered fax services, but unfortunately it was after hours.

Finally, I decided to use an online fax service. Not having ever used an online fax service, I asked ChatGPT to recommend one with a good reputation and fair pricing. It offered a couple of options, and I somewhat randomly went with FaxZero.com, although I am sure that there are many other online fax services with competitive offerings. The process was simple. I first scanned my 4-page document to a PDF file. I then entered information about the sender and receiver and attached my PDF file. There was an option to enter text for a cover page, but I left it blank. Then I paid $3.29 via credit card (note that sending faxes up to 3 pages is free) and sent the fax. Email confirmations were provided upon initial transmission and successful sending of the fax.

I appreciated many aspects of the online fax service. First, we could send a fax without purchasing a physical fax machine. Second, we could send the fax from the comfort of our own home and avoid locating and driving to a physical store, and potentially waiting in a line or waiting for an agent to assist us. Third, we did not have to wait for the fax to transmit—instead, we simply received an email notification upon job completion.

If I was ever asked to fax something, I’d still first search for better alternatives such as email, but if I absolutely had to fax something, I’d definitely consider using an online fax service again due to its convenience and lower cost in comparison to in-store options.