California’s push to ban technology used for ‘ghost guns’ finds unlikely foe in Hollywood

California has some of the nation’s toughest gun laws, but state lawmakers are concerned that a new technology is allowing criminals to obtain firearms by building them from scratch. By using 3-D printers, they warn, lawbreakers are able to make key components of untraceable “ghost guns” with the press of a button.

Ghost guns, which authorities say make it more difficult to investigate shootings because they lack serial numbers, have been a growing problem for law enforcement nationwide. According to federal data, the number of privately made firearms recovered in crimes surged from more than 1,600 in 2017 to nearly 27,500 in 2023. California leads the nation in recoveries over that period.

In response, legislators are seeking to mandate that all 3-D printers sold in the state come equipped with software that prohibits users from making triggers and other gun parts. A bill passed the Assembly in May and is advancing through the Senate.

But the proposal has drawn opposition from a diverse coalition, which includes civil liberties groups, tech companies and 3-D printing enthusiasts as well as Hollywood effects studios, who argue that “firearm blocking software” will also prohibit legitimate designs and expose makers to government or corporate surveillance.

Inside a San Fernando workshop, Samuel McBride makes movie monsters come to life for the camera. One of his latest creations, an animatronic hand, clutches when he pulls a trigger that he built using a 3-D printer.

McBride says the technology has transformed the work at Legacy Effects, where he is a lab manager, but he’s worried it will soon be off-limits because of a proposed change in California law.

McBride fears the law would interfere with the making of devices like the one that activates his lifelike hand.

“If I just took apart this trigger and put it on a printer, how is anyone, computer or human, going to tell me how I intend to use it?” he asked.

Backers of the proposed law say it has the potential to help save lives.

“As gun violence continues to devastate our communities, we cannot allow 3-D printing technology to become a new pipeline for untraceable weapons,” said Assemblymember Rebecca Bauer-Kahan, the bill’s author.

Critics of the proposed California law note that 3-D printed guns represent a small subset of ghost guns recovered by law enforcement at crime scenes. According to the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, most “privately made firearms” recovered by police are assembled from mail-order kits or unfinished parts rather than printed at home.

Jorge Perez of Monster City Studios holds a sculpture made with a large, industrial 3-D printer.

(Ronaldo Bolaños / Los Angeles Times)

“This fight is not over whether ghost guns are dangerous,” said David Tobin, an independent creator leading the coalition. “It is over whether the state can or should require a consumer tool to surveil a person’s designs before they are allowed to make something.”

Everytown for Gun Safety, a national nonprofit that advocates for gun control and has pushed for the passage of California’s bill, pointed to rising 3-D printed firearm recoveries across 20 major cities and warned that homemade plastic parts can help people bypass background checks or turn handguns into automatic weapons.

Krystal LoPilato, who advocates for policy at Everytown, said the group has successfully guided a similar bill through the New York state Legislature.

A handgun frame made using a 3-D printer is held for display at the office of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

(Alex Brandon / Associated Press)

LoPilato said the policy aims to be proactive, rather than allowing more violence to take place before regulating the problem. Opponents counter that California already bars unlawful firearm manufacturing with 3-D printers, and that ghost gun recoveries have declined since the state adopted a series of new laws and enforcement efforts.

A June 1 letter to lawmakers, signed by a group of 3-D printing companies, stagecraft and prop-making studios and industry stakeholders, argued that AB 2047 raises 1st Amendment concerns and would harm businesses. The letter was signed by a wide variety of companies and individuals, including Prusa Research, a prominent 3-D printer manufacturer.

“To an algorithm, a gun barrel and a piece of pipe are the same grooved cylinder,” Jakub Kmošek, head of public affairs at Prusa, said in a statement to The Times. “This bill will only make it harder to build, repair, experiment, and innovate in California.”

Alan Scott, Legacy Effects’ co-founder, said 3-D printing has become central to the company’s survival in an industry where budgets are tighter and deadlines are shorter.

“Everything’s just got to be done faster these days. You don’t get to reduce the quality. We couldn’t stay in business if we weren’t 3-D printing,” Scott said.

To solve this problem, Bauer-Kahan put an entertainment industry exception in the bill, exempting “printers manufactured for and sold exclusively to entertainment industry stagecraft and propmaking studios” from the software requirement.

McBride, Legacy’s 3-D lab manager, said those printers do not really exist.

Legacy uses the same general-purpose machines available to other businesses willing to invest in the equipment, and no printers are marketed exclusively for Hollywood, he said.

1

2

1. A 3-D printed sculpture concept at Monster City, a special effects studio in Santa Clarita. (Ronaldo Bolaños / Los Angeles Times) 2. 3-D printing advocate David Tobin showcases a robotics kit at Monster City. (Ronaldo Bolaños / Los Angeles Times)

Legacy also worries about privacy. Major studios require strict secrecy before a movie or show is released. To accommodate this, the company shares design files through encrypted servers and protected internal systems.

“We’ve invested hundreds of thousands of dollars to bring all that technology here under the umbrella of our NDAs and our IP protection,” McBride said.

Bauer-Kahan noted at a Senate hearing that she is working to address concerns raised by 3-D printing users and industries that rely on the technology.

Paul Powers, chief executive of Physna, a company whose technology could be used to block gun parts on 3-D printers, said the strongest criticisms of AB 2047 “misunderstand how the software works.”

“Something that vaguely looks like a gun part is not considered to be a match,” he said.

Powers also responded to surveillance concerns by clarifying that his company’s software only blocks the printer from making prohibited parts — it doesn’t flag them to authorities or log users’ intellectual property.

“There’s no communication with anyone; it doesn’t go anywhere,” he said.

But Marleen Vogelaar, chief executive of Thangs3D, a platform for independent creators to share and sell 3-D printable designs, said that answer does not resolve her broader concerns about how AB 2047 would work in practice.

“These databases will always lag behind innovation and can be easily circumvented and generate false positives that block legal designs and wrongly flag everyday makers,” she said at a Senate hearing this month. “The bill also creates serious privacy and security risks by giving third parties access to analyze designer’s files. That threatens intellectual property and adds digital surveillance in a state that values data privacy.”

If the bill passes, the state’s Department of Justice would publish a roster of compliant printers. Printers not on the list would be banned from sale or transfer in California beginning in December 2029.

Aubrey Rodriguez, a legislative advocate with American Civil Liberties Union California Action, an advocacy organization formed by the ACLU’s three affiliates in the state, said the bill would ask ordinary users, schools and businesses to accept a new layer of control based on software they still do not trust.

Rodriguez said the proposal risks creating “a permanent back door into the privacy of our own homes, ripe for exploitation.”

“Once this new infrastructure exists, it is a simple software update away from tracking political dissent or preventing 3-D printing designs deemed inappropriate,” Rodriguez said.

California has some of the nation’s toughest gun laws, but state lawmakers are concerned that a new technology is allowing criminals to obtain firearms by building them from scratch. By using 3-D printers, they warn, lawbreakers are able to make key components of untraceable “ghost guns” with the press of a button.

Ghost guns, which authorities say make it more difficult to investigate shootings because they lack serial numbers, have been a growing problem for law enforcement nationwide. According to federal data, the number of privately made firearms recovered in crimes surged from more than 1,600 in 2017 to nearly 27,500 in 2023. California leads the nation in recoveries over that period.

In response, legislators are seeking to mandate that all 3-D printers sold in the state come equipped with software that prohibits users from making triggers and other gun parts. A bill passed the Assembly in May and is advancing through the Senate.

But the proposal has drawn opposition from a diverse coalition, which includes civil liberties groups, tech companies and 3-D printing enthusiasts as well as Hollywood effects studios, who argue that “firearm blocking software” will also prohibit legitimate designs and expose makers to government or corporate surveillance.

Inside a San Fernando workshop, Samuel McBride makes movie monsters come to life for the camera. One of his latest creations, an animatronic hand, clutches when he pulls a trigger that he built using a 3-D printer.

McBride says the technology has transformed the work at Legacy Effects, where he is a lab manager, but he’s worried it will soon be off-limits because of a proposed change in California law.

McBride fears the law would interfere with the making of devices like the one that activates his lifelike hand.

“If I just took apart this trigger and put it on a printer, how is anyone, computer or human, going to tell me how I intend to use it?” he asked.

Backers of the proposed law say it has the potential to help save lives.

“As gun violence continues to devastate our communities, we cannot allow 3-D printing technology to become a new pipeline for untraceable weapons,” said Assemblymember Rebecca Bauer-Kahan, the bill’s author.

Critics of the proposed California law note that 3-D printed guns represent a small subset of ghost guns recovered by law enforcement at crime scenes. According to the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, most “privately made firearms” recovered by police are assembled from mail-order kits or unfinished parts rather than printed at home.

Jorge Perez of Monster City Studios holds a sculpture made with a large, industrial 3-D printer.

(Ronaldo Bolaños / Los Angeles Times)

“This fight is not over whether ghost guns are dangerous,” said David Tobin, an independent creator leading the coalition. “It is over whether the state can or should require a consumer tool to surveil a person’s designs before they are allowed to make something.”

Everytown for Gun Safety, a national nonprofit that advocates for gun control and has pushed for the passage of California’s bill, pointed to rising 3-D printed firearm recoveries across 20 major cities and warned that homemade plastic parts can help people bypass background checks or turn handguns into automatic weapons.

Krystal LoPilato, who advocates for policy at Everytown, said the group has successfully guided a similar bill through the New York state Legislature.

A handgun frame made using a 3-D printer is held for display at the office of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

(Alex Brandon / Associated Press)

LoPilato said the policy aims to be proactive, rather than allowing more violence to take place before regulating the problem. Opponents counter that California already bars unlawful firearm manufacturing with 3-D printers, and that ghost gun recoveries have declined since the state adopted a series of new laws and enforcement efforts.

A June 1 letter to lawmakers, signed by a group of 3-D printing companies, stagecraft and prop-making studios and industry stakeholders, argued that AB 2047 raises 1st Amendment concerns and would harm businesses. The letter was signed by a wide variety of companies and individuals, including Prusa Research, a prominent 3-D printer manufacturer.

“To an algorithm, a gun barrel and a piece of pipe are the same grooved cylinder,” Jakub Kmošek, head of public affairs at Prusa, said in a statement to The Times. “This bill will only make it harder to build, repair, experiment, and innovate in California.”

Alan Scott, Legacy Effects’ co-founder, said 3-D printing has become central to the company’s survival in an industry where budgets are tighter and deadlines are shorter.

“Everything’s just got to be done faster these days. You don’t get to reduce the quality. We couldn’t stay in business if we weren’t 3-D printing,” Scott said.

To solve this problem, Bauer-Kahan put an entertainment industry exception in the bill, exempting “printers manufactured for and sold exclusively to entertainment industry stagecraft and propmaking studios” from the software requirement.

McBride, Legacy’s 3-D lab manager, said those printers do not really exist.

Legacy uses the same general-purpose machines available to other businesses willing to invest in the equipment, and no printers are marketed exclusively for Hollywood, he said.

1

2

1. A 3-D printed sculpture concept at Monster City, a special effects studio in Santa Clarita. (Ronaldo Bolaños / Los Angeles Times) 2. 3-D printing advocate David Tobin showcases a robotics kit at Monster City. (Ronaldo Bolaños / Los Angeles Times)

Legacy also worries about privacy. Major studios require strict secrecy before a movie or show is released. To accommodate this, the company shares design files through encrypted servers and protected internal systems.

“We’ve invested hundreds of thousands of dollars to bring all that technology here under the umbrella of our NDAs and our IP protection,” McBride said.

Bauer-Kahan noted at a Senate hearing that she is working to address concerns raised by 3-D printing users and industries that rely on the technology.

Paul Powers, chief executive of Physna, a company whose technology could be used to block gun parts on 3-D printers, said the strongest criticisms of AB 2047 “misunderstand how the software works.”

“Something that vaguely looks like a gun part is not considered to be a match,” he said.

Powers also responded to surveillance concerns by clarifying that his company’s software only blocks the printer from making prohibited parts — it doesn’t flag them to authorities or log users’ intellectual property.

“There’s no communication with anyone; it doesn’t go anywhere,” he said.

But Marleen Vogelaar, chief executive of Thangs3D, a platform for independent creators to share and sell 3-D printable designs, said that answer does not resolve her broader concerns about how AB 2047 would work in practice.

“These databases will always lag behind innovation and can be easily circumvented and generate false positives that block legal designs and wrongly flag everyday makers,” she said at a Senate hearing this month. “The bill also creates serious privacy and security risks by giving third parties access to analyze designer’s files. That threatens intellectual property and adds digital surveillance in a state that values data privacy.”

If the bill passes, the state’s Department of Justice would publish a roster of compliant printers. Printers not on the list would be banned from sale or transfer in California beginning in December 2029.

Aubrey Rodriguez, a legislative advocate with American Civil Liberties Union California Action, an advocacy organization formed by the ACLU’s three affiliates in the state, said the bill would ask ordinary users, schools and businesses to accept a new layer of control based on software they still do not trust.

Rodriguez said the proposal risks creating “a permanent back door into the privacy of our own homes, ripe for exploitation.”

“Once this new infrastructure exists, it is a simple software update away from tracking political dissent or preventing 3-D printing designs deemed inappropriate,” Rodriguez said.

California has some of the nation’s toughest gun laws, but state lawmakers are concerned that a new technology is allowing criminals to obtain firearms by building them from scratch. By using 3-D printers, they warn, lawbreakers are able to make key components of untraceable “ghost guns” with the press of a button.

Ghost guns, which authorities say make it more difficult to investigate shootings because they lack serial numbers, have been a growing problem for law enforcement nationwide. According to federal data, the number of privately made firearms recovered in crimes surged from more than 1,600 in 2017 to nearly 27,500 in 2023. California leads the nation in recoveries over that period.

In response, legislators are seeking to mandate that all 3-D printers sold in the state come equipped with software that prohibits users from making triggers and other gun parts. A bill passed the Assembly in May and is advancing through the Senate.

But the proposal has drawn opposition from a diverse coalition, which includes civil liberties groups, tech companies and 3-D printing enthusiasts as well as Hollywood effects studios, who argue that “firearm blocking software” will also prohibit legitimate designs and expose makers to government or corporate surveillance.

Inside a San Fernando workshop, Samuel McBride makes movie monsters come to life for the camera. One of his latest creations, an animatronic hand, clutches when he pulls a trigger that he built using a 3-D printer.

McBride says the technology has transformed the work at Legacy Effects, where he is a lab manager, but he’s worried it will soon be off-limits because of a proposed change in California law.

McBride fears the law would interfere with the making of devices like the one that activates his lifelike hand.

“If I just took apart this trigger and put it on a printer, how is anyone, computer or human, going to tell me how I intend to use it?” he asked.

Backers of the proposed law say it has the potential to help save lives.

“As gun violence continues to devastate our communities, we cannot allow 3-D printing technology to become a new pipeline for untraceable weapons,” said Assemblymember Rebecca Bauer-Kahan, the bill’s author.

Critics of the proposed California law note that 3-D printed guns represent a small subset of ghost guns recovered by law enforcement at crime scenes. According to the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, most “privately made firearms” recovered by police are assembled from mail-order kits or unfinished parts rather than printed at home.

Jorge Perez of Monster City Studios holds a sculpture made with a large, industrial 3-D printer.

(Ronaldo Bolaños / Los Angeles Times)

“This fight is not over whether ghost guns are dangerous,” said David Tobin, an independent creator leading the coalition. “It is over whether the state can or should require a consumer tool to surveil a person’s designs before they are allowed to make something.”

Everytown for Gun Safety, a national nonprofit that advocates for gun control and has pushed for the passage of California’s bill, pointed to rising 3-D printed firearm recoveries across 20 major cities and warned that homemade plastic parts can help people bypass background checks or turn handguns into automatic weapons.

Krystal LoPilato, who advocates for policy at Everytown, said the group has successfully guided a similar bill through the New York state Legislature.

A handgun frame made using a 3-D printer is held for display at the office of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

(Alex Brandon / Associated Press)

LoPilato said the policy aims to be proactive, rather than allowing more violence to take place before regulating the problem. Opponents counter that California already bars unlawful firearm manufacturing with 3-D printers, and that ghost gun recoveries have declined since the state adopted a series of new laws and enforcement efforts.

A June 1 letter to lawmakers, signed by a group of 3-D printing companies, stagecraft and prop-making studios and industry stakeholders, argued that AB 2047 raises 1st Amendment concerns and would harm businesses. The letter was signed by a wide variety of companies and individuals, including Prusa Research, a prominent 3-D printer manufacturer.

“To an algorithm, a gun barrel and a piece of pipe are the same grooved cylinder,” Jakub Kmošek, head of public affairs at Prusa, said in a statement to The Times. “This bill will only make it harder to build, repair, experiment, and innovate in California.”

Alan Scott, Legacy Effects’ co-founder, said 3-D printing has become central to the company’s survival in an industry where budgets are tighter and deadlines are shorter.

“Everything’s just got to be done faster these days. You don’t get to reduce the quality. We couldn’t stay in business if we weren’t 3-D printing,” Scott said.

To solve this problem, Bauer-Kahan put an entertainment industry exception in the bill, exempting “printers manufactured for and sold exclusively to entertainment industry stagecraft and propmaking studios” from the software requirement.

McBride, Legacy’s 3-D lab manager, said those printers do not really exist.

Legacy uses the same general-purpose machines available to other businesses willing to invest in the equipment, and no printers are marketed exclusively for Hollywood, he said.

1

2

1. A 3-D printed sculpture concept at Monster City, a special effects studio in Santa Clarita. (Ronaldo Bolaños / Los Angeles Times) 2. 3-D printing advocate David Tobin showcases a robotics kit at Monster City. (Ronaldo Bolaños / Los Angeles Times)

Legacy also worries about privacy. Major studios require strict secrecy before a movie or show is released. To accommodate this, the company shares design files through encrypted servers and protected internal systems.

“We’ve invested hundreds of thousands of dollars to bring all that technology here under the umbrella of our NDAs and our IP protection,” McBride said.

Bauer-Kahan noted at a Senate hearing that she is working to address concerns raised by 3-D printing users and industries that rely on the technology.

Paul Powers, chief executive of Physna, a company whose technology could be used to block gun parts on 3-D printers, said the strongest criticisms of AB 2047 “misunderstand how the software works.”

“Something that vaguely looks like a gun part is not considered to be a match,” he said.

Powers also responded to surveillance concerns by clarifying that his company’s software only blocks the printer from making prohibited parts — it doesn’t flag them to authorities or log users’ intellectual property.

“There’s no communication with anyone; it doesn’t go anywhere,” he said.

But Marleen Vogelaar, chief executive of Thangs3D, a platform for independent creators to share and sell 3-D printable designs, said that answer does not resolve her broader concerns about how AB 2047 would work in practice.

“These databases will always lag behind innovation and can be easily circumvented and generate false positives that block legal designs and wrongly flag everyday makers,” she said at a Senate hearing this month. “The bill also creates serious privacy and security risks by giving third parties access to analyze designer’s files. That threatens intellectual property and adds digital surveillance in a state that values data privacy.”

If the bill passes, the state’s Department of Justice would publish a roster of compliant printers. Printers not on the list would be banned from sale or transfer in California beginning in December 2029.

Aubrey Rodriguez, a legislative advocate with American Civil Liberties Union California Action, an advocacy organization formed by the ACLU’s three affiliates in the state, said the bill would ask ordinary users, schools and businesses to accept a new layer of control based on software they still do not trust.

Rodriguez said the proposal risks creating “a permanent back door into the privacy of our own homes, ripe for exploitation.”

“Once this new infrastructure exists, it is a simple software update away from tracking political dissent or preventing 3-D printing designs deemed inappropriate,” Rodriguez said.

California has some of the nation’s toughest gun laws, but state lawmakers are concerned that a new technology is allowing criminals to obtain firearms by building them from scratch. By using 3-D printers, they warn, lawbreakers are able to make key components of untraceable “ghost guns” with the press of a button.

Ghost guns, which authorities say make it more difficult to investigate shootings because they lack serial numbers, have been a growing problem for law enforcement nationwide. According to federal data, the number of privately made firearms recovered in crimes surged from more than 1,600 in 2017 to nearly 27,500 in 2023. California leads the nation in recoveries over that period.

In response, legislators are seeking to mandate that all 3-D printers sold in the state come equipped with software that prohibits users from making triggers and other gun parts. A bill passed the Assembly in May and is advancing through the Senate.

But the proposal has drawn opposition from a diverse coalition, which includes civil liberties groups, tech companies and 3-D printing enthusiasts as well as Hollywood effects studios, who argue that “firearm blocking software” will also prohibit legitimate designs and expose makers to government or corporate surveillance.

Inside a San Fernando workshop, Samuel McBride makes movie monsters come to life for the camera. One of his latest creations, an animatronic hand, clutches when he pulls a trigger that he built using a 3-D printer.

McBride says the technology has transformed the work at Legacy Effects, where he is a lab manager, but he’s worried it will soon be off-limits because of a proposed change in California law.

McBride fears the law would interfere with the making of devices like the one that activates his lifelike hand.

“If I just took apart this trigger and put it on a printer, how is anyone, computer or human, going to tell me how I intend to use it?” he asked.

Backers of the proposed law say it has the potential to help save lives.

“As gun violence continues to devastate our communities, we cannot allow 3-D printing technology to become a new pipeline for untraceable weapons,” said Assemblymember Rebecca Bauer-Kahan, the bill’s author.

Critics of the proposed California law note that 3-D printed guns represent a small subset of ghost guns recovered by law enforcement at crime scenes. According to the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, most “privately made firearms” recovered by police are assembled from mail-order kits or unfinished parts rather than printed at home.

Jorge Perez of Monster City Studios holds a sculpture made with a large, industrial 3-D printer.

(Ronaldo Bolaños / Los Angeles Times)

“This fight is not over whether ghost guns are dangerous,” said David Tobin, an independent creator leading the coalition. “It is over whether the state can or should require a consumer tool to surveil a person’s designs before they are allowed to make something.”

Everytown for Gun Safety, a national nonprofit that advocates for gun control and has pushed for the passage of California’s bill, pointed to rising 3-D printed firearm recoveries across 20 major cities and warned that homemade plastic parts can help people bypass background checks or turn handguns into automatic weapons.

Krystal LoPilato, who advocates for policy at Everytown, said the group has successfully guided a similar bill through the New York state Legislature.

A handgun frame made using a 3-D printer is held for display at the office of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

(Alex Brandon / Associated Press)

LoPilato said the policy aims to be proactive, rather than allowing more violence to take place before regulating the problem. Opponents counter that California already bars unlawful firearm manufacturing with 3-D printers, and that ghost gun recoveries have declined since the state adopted a series of new laws and enforcement efforts.

A June 1 letter to lawmakers, signed by a group of 3-D printing companies, stagecraft and prop-making studios and industry stakeholders, argued that AB 2047 raises 1st Amendment concerns and would harm businesses. The letter was signed by a wide variety of companies and individuals, including Prusa Research, a prominent 3-D printer manufacturer.

“To an algorithm, a gun barrel and a piece of pipe are the same grooved cylinder,” Jakub Kmošek, head of public affairs at Prusa, said in a statement to The Times. “This bill will only make it harder to build, repair, experiment, and innovate in California.”

Alan Scott, Legacy Effects’ co-founder, said 3-D printing has become central to the company’s survival in an industry where budgets are tighter and deadlines are shorter.

“Everything’s just got to be done faster these days. You don’t get to reduce the quality. We couldn’t stay in business if we weren’t 3-D printing,” Scott said.

To solve this problem, Bauer-Kahan put an entertainment industry exception in the bill, exempting “printers manufactured for and sold exclusively to entertainment industry stagecraft and propmaking studios” from the software requirement.

McBride, Legacy’s 3-D lab manager, said those printers do not really exist.

Legacy uses the same general-purpose machines available to other businesses willing to invest in the equipment, and no printers are marketed exclusively for Hollywood, he said.

1

2

1. A 3-D printed sculpture concept at Monster City, a special effects studio in Santa Clarita. (Ronaldo Bolaños / Los Angeles Times) 2. 3-D printing advocate David Tobin showcases a robotics kit at Monster City. (Ronaldo Bolaños / Los Angeles Times)

Legacy also worries about privacy. Major studios require strict secrecy before a movie or show is released. To accommodate this, the company shares design files through encrypted servers and protected internal systems.

“We’ve invested hundreds of thousands of dollars to bring all that technology here under the umbrella of our NDAs and our IP protection,” McBride said.

Bauer-Kahan noted at a Senate hearing that she is working to address concerns raised by 3-D printing users and industries that rely on the technology.

Paul Powers, chief executive of Physna, a company whose technology could be used to block gun parts on 3-D printers, said the strongest criticisms of AB 2047 “misunderstand how the software works.”

“Something that vaguely looks like a gun part is not considered to be a match,” he said.

Powers also responded to surveillance concerns by clarifying that his company’s software only blocks the printer from making prohibited parts — it doesn’t flag them to authorities or log users’ intellectual property.

“There’s no communication with anyone; it doesn’t go anywhere,” he said.

But Marleen Vogelaar, chief executive of Thangs3D, a platform for independent creators to share and sell 3-D printable designs, said that answer does not resolve her broader concerns about how AB 2047 would work in practice.

“These databases will always lag behind innovation and can be easily circumvented and generate false positives that block legal designs and wrongly flag everyday makers,” she said at a Senate hearing this month. “The bill also creates serious privacy and security risks by giving third parties access to analyze designer’s files. That threatens intellectual property and adds digital surveillance in a state that values data privacy.”

If the bill passes, the state’s Department of Justice would publish a roster of compliant printers. Printers not on the list would be banned from sale or transfer in California beginning in December 2029.

Aubrey Rodriguez, a legislative advocate with American Civil Liberties Union California Action, an advocacy organization formed by the ACLU’s three affiliates in the state, said the bill would ask ordinary users, schools and businesses to accept a new layer of control based on software they still do not trust.

Rodriguez said the proposal risks creating “a permanent back door into the privacy of our own homes, ripe for exploitation.”

“Once this new infrastructure exists, it is a simple software update away from tracking political dissent or preventing 3-D printing designs deemed inappropriate,” Rodriguez said.

California has some of the nation’s toughest gun laws, but state lawmakers are concerned that a new technology is allowing criminals to obtain firearms by building them from scratch. By using 3-D printers, they warn, lawbreakers are able to make key components of untraceable “ghost guns” with the press of a button.

Ghost guns, which authorities say make it more difficult to investigate shootings because they lack serial numbers, have been a growing problem for law enforcement nationwide. According to federal data, the number of privately made firearms recovered in crimes surged from more than 1,600 in 2017 to nearly 27,500 in 2023. California leads the nation in recoveries over that period.

In response, legislators are seeking to mandate that all 3-D printers sold in the state come equipped with software that prohibits users from making triggers and other gun parts. A bill passed the Assembly in May and is advancing through the Senate.

But the proposal has drawn opposition from a diverse coalition, which includes civil liberties groups, tech companies and 3-D printing enthusiasts as well as Hollywood effects studios, who argue that “firearm blocking software” will also prohibit legitimate designs and expose makers to government or corporate surveillance.

Inside a San Fernando workshop, Samuel McBride makes movie monsters come to life for the camera. One of his latest creations, an animatronic hand, clutches when he pulls a trigger that he built using a 3-D printer.

McBride says the technology has transformed the work at Legacy Effects, where he is a lab manager, but he’s worried it will soon be off-limits because of a proposed change in California law.

McBride fears the law would interfere with the making of devices like the one that activates his lifelike hand.

“If I just took apart this trigger and put it on a printer, how is anyone, computer or human, going to tell me how I intend to use it?” he asked.

Backers of the proposed law say it has the potential to help save lives.

“As gun violence continues to devastate our communities, we cannot allow 3-D printing technology to become a new pipeline for untraceable weapons,” said Assemblymember Rebecca Bauer-Kahan, the bill’s author.

Critics of the proposed California law note that 3-D printed guns represent a small subset of ghost guns recovered by law enforcement at crime scenes. According to the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, most “privately made firearms” recovered by police are assembled from mail-order kits or unfinished parts rather than printed at home.

Jorge Perez of Monster City Studios holds a sculpture made with a large, industrial 3-D printer.

(Ronaldo Bolaños / Los Angeles Times)

“This fight is not over whether ghost guns are dangerous,” said David Tobin, an independent creator leading the coalition. “It is over whether the state can or should require a consumer tool to surveil a person’s designs before they are allowed to make something.”

Everytown for Gun Safety, a national nonprofit that advocates for gun control and has pushed for the passage of California’s bill, pointed to rising 3-D printed firearm recoveries across 20 major cities and warned that homemade plastic parts can help people bypass background checks or turn handguns into automatic weapons.

Krystal LoPilato, who advocates for policy at Everytown, said the group has successfully guided a similar bill through the New York state Legislature.

A handgun frame made using a 3-D printer is held for display at the office of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

(Alex Brandon / Associated Press)

LoPilato said the policy aims to be proactive, rather than allowing more violence to take place before regulating the problem. Opponents counter that California already bars unlawful firearm manufacturing with 3-D printers, and that ghost gun recoveries have declined since the state adopted a series of new laws and enforcement efforts.

A June 1 letter to lawmakers, signed by a group of 3-D printing companies, stagecraft and prop-making studios and industry stakeholders, argued that AB 2047 raises 1st Amendment concerns and would harm businesses. The letter was signed by a wide variety of companies and individuals, including Prusa Research, a prominent 3-D printer manufacturer.

“To an algorithm, a gun barrel and a piece of pipe are the same grooved cylinder,” Jakub Kmošek, head of public affairs at Prusa, said in a statement to The Times. “This bill will only make it harder to build, repair, experiment, and innovate in California.”

Alan Scott, Legacy Effects’ co-founder, said 3-D printing has become central to the company’s survival in an industry where budgets are tighter and deadlines are shorter.

“Everything’s just got to be done faster these days. You don’t get to reduce the quality. We couldn’t stay in business if we weren’t 3-D printing,” Scott said.

To solve this problem, Bauer-Kahan put an entertainment industry exception in the bill, exempting “printers manufactured for and sold exclusively to entertainment industry stagecraft and propmaking studios” from the software requirement.

McBride, Legacy’s 3-D lab manager, said those printers do not really exist.

Legacy uses the same general-purpose machines available to other businesses willing to invest in the equipment, and no printers are marketed exclusively for Hollywood, he said.

1

2

1. A 3-D printed sculpture concept at Monster City, a special effects studio in Santa Clarita. (Ronaldo Bolaños / Los Angeles Times) 2. 3-D printing advocate David Tobin showcases a robotics kit at Monster City. (Ronaldo Bolaños / Los Angeles Times)

Legacy also worries about privacy. Major studios require strict secrecy before a movie or show is released. To accommodate this, the company shares design files through encrypted servers and protected internal systems.

“We’ve invested hundreds of thousands of dollars to bring all that technology here under the umbrella of our NDAs and our IP protection,” McBride said.

Bauer-Kahan noted at a Senate hearing that she is working to address concerns raised by 3-D printing users and industries that rely on the technology.

Paul Powers, chief executive of Physna, a company whose technology could be used to block gun parts on 3-D printers, said the strongest criticisms of AB 2047 “misunderstand how the software works.”

“Something that vaguely looks like a gun part is not considered to be a match,” he said.

Powers also responded to surveillance concerns by clarifying that his company’s software only blocks the printer from making prohibited parts — it doesn’t flag them to authorities or log users’ intellectual property.

“There’s no communication with anyone; it doesn’t go anywhere,” he said.

But Marleen Vogelaar, chief executive of Thangs3D, a platform for independent creators to share and sell 3-D printable designs, said that answer does not resolve her broader concerns about how AB 2047 would work in practice.

“These databases will always lag behind innovation and can be easily circumvented and generate false positives that block legal designs and wrongly flag everyday makers,” she said at a Senate hearing this month. “The bill also creates serious privacy and security risks by giving third parties access to analyze designer’s files. That threatens intellectual property and adds digital surveillance in a state that values data privacy.”

If the bill passes, the state’s Department of Justice would publish a roster of compliant printers. Printers not on the list would be banned from sale or transfer in California beginning in December 2029.

Aubrey Rodriguez, a legislative advocate with American Civil Liberties Union California Action, an advocacy organization formed by the ACLU’s three affiliates in the state, said the bill would ask ordinary users, schools and businesses to accept a new layer of control based on software they still do not trust.

Rodriguez said the proposal risks creating “a permanent back door into the privacy of our own homes, ripe for exploitation.”

“Once this new infrastructure exists, it is a simple software update away from tracking political dissent or preventing 3-D printing designs deemed inappropriate,” Rodriguez said.

California has some of the nation’s toughest gun laws, but state lawmakers are concerned that a new technology is allowing criminals to obtain firearms by building them from scratch. By using 3-D printers, they warn, lawbreakers are able to make key components of untraceable “ghost guns” with the press of a button.

Ghost guns, which authorities say make it more difficult to investigate shootings because they lack serial numbers, have been a growing problem for law enforcement nationwide. According to federal data, the number of privately made firearms recovered in crimes surged from more than 1,600 in 2017 to nearly 27,500 in 2023. California leads the nation in recoveries over that period.

In response, legislators are seeking to mandate that all 3-D printers sold in the state come equipped with software that prohibits users from making triggers and other gun parts. A bill passed the Assembly in May and is advancing through the Senate.

But the proposal has drawn opposition from a diverse coalition, which includes civil liberties groups, tech companies and 3-D printing enthusiasts as well as Hollywood effects studios, who argue that “firearm blocking software” will also prohibit legitimate designs and expose makers to government or corporate surveillance.

Inside a San Fernando workshop, Samuel McBride makes movie monsters come to life for the camera. One of his latest creations, an animatronic hand, clutches when he pulls a trigger that he built using a 3-D printer.

McBride says the technology has transformed the work at Legacy Effects, where he is a lab manager, but he’s worried it will soon be off-limits because of a proposed change in California law.

McBride fears the law would interfere with the making of devices like the one that activates his lifelike hand.

“If I just took apart this trigger and put it on a printer, how is anyone, computer or human, going to tell me how I intend to use it?” he asked.

Backers of the proposed law say it has the potential to help save lives.

“As gun violence continues to devastate our communities, we cannot allow 3-D printing technology to become a new pipeline for untraceable weapons,” said Assemblymember Rebecca Bauer-Kahan, the bill’s author.

Critics of the proposed California law note that 3-D printed guns represent a small subset of ghost guns recovered by law enforcement at crime scenes. According to the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, most “privately made firearms” recovered by police are assembled from mail-order kits or unfinished parts rather than printed at home.

Jorge Perez of Monster City Studios holds a sculpture made with a large, industrial 3-D printer.

(Ronaldo Bolaños / Los Angeles Times)

“This fight is not over whether ghost guns are dangerous,” said David Tobin, an independent creator leading the coalition. “It is over whether the state can or should require a consumer tool to surveil a person’s designs before they are allowed to make something.”

Everytown for Gun Safety, a national nonprofit that advocates for gun control and has pushed for the passage of California’s bill, pointed to rising 3-D printed firearm recoveries across 20 major cities and warned that homemade plastic parts can help people bypass background checks or turn handguns into automatic weapons.

Krystal LoPilato, who advocates for policy at Everytown, said the group has successfully guided a similar bill through the New York state Legislature.

A handgun frame made using a 3-D printer is held for display at the office of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

(Alex Brandon / Associated Press)

LoPilato said the policy aims to be proactive, rather than allowing more violence to take place before regulating the problem. Opponents counter that California already bars unlawful firearm manufacturing with 3-D printers, and that ghost gun recoveries have declined since the state adopted a series of new laws and enforcement efforts.

A June 1 letter to lawmakers, signed by a group of 3-D printing companies, stagecraft and prop-making studios and industry stakeholders, argued that AB 2047 raises 1st Amendment concerns and would harm businesses. The letter was signed by a wide variety of companies and individuals, including Prusa Research, a prominent 3-D printer manufacturer.

“To an algorithm, a gun barrel and a piece of pipe are the same grooved cylinder,” Jakub Kmošek, head of public affairs at Prusa, said in a statement to The Times. “This bill will only make it harder to build, repair, experiment, and innovate in California.”

Alan Scott, Legacy Effects’ co-founder, said 3-D printing has become central to the company’s survival in an industry where budgets are tighter and deadlines are shorter.

“Everything’s just got to be done faster these days. You don’t get to reduce the quality. We couldn’t stay in business if we weren’t 3-D printing,” Scott said.

To solve this problem, Bauer-Kahan put an entertainment industry exception in the bill, exempting “printers manufactured for and sold exclusively to entertainment industry stagecraft and propmaking studios” from the software requirement.

McBride, Legacy’s 3-D lab manager, said those printers do not really exist.

Legacy uses the same general-purpose machines available to other businesses willing to invest in the equipment, and no printers are marketed exclusively for Hollywood, he said.

1

2

1. A 3-D printed sculpture concept at Monster City, a special effects studio in Santa Clarita. (Ronaldo Bolaños / Los Angeles Times) 2. 3-D printing advocate David Tobin showcases a robotics kit at Monster City. (Ronaldo Bolaños / Los Angeles Times)

Legacy also worries about privacy. Major studios require strict secrecy before a movie or show is released. To accommodate this, the company shares design files through encrypted servers and protected internal systems.

“We’ve invested hundreds of thousands of dollars to bring all that technology here under the umbrella of our NDAs and our IP protection,” McBride said.

Bauer-Kahan noted at a Senate hearing that she is working to address concerns raised by 3-D printing users and industries that rely on the technology.

Paul Powers, chief executive of Physna, a company whose technology could be used to block gun parts on 3-D printers, said the strongest criticisms of AB 2047 “misunderstand how the software works.”

“Something that vaguely looks like a gun part is not considered to be a match,” he said.

Powers also responded to surveillance concerns by clarifying that his company’s software only blocks the printer from making prohibited parts — it doesn’t flag them to authorities or log users’ intellectual property.

“There’s no communication with anyone; it doesn’t go anywhere,” he said.

But Marleen Vogelaar, chief executive of Thangs3D, a platform for independent creators to share and sell 3-D printable designs, said that answer does not resolve her broader concerns about how AB 2047 would work in practice.

“These databases will always lag behind innovation and can be easily circumvented and generate false positives that block legal designs and wrongly flag everyday makers,” she said at a Senate hearing this month. “The bill also creates serious privacy and security risks by giving third parties access to analyze designer’s files. That threatens intellectual property and adds digital surveillance in a state that values data privacy.”

If the bill passes, the state’s Department of Justice would publish a roster of compliant printers. Printers not on the list would be banned from sale or transfer in California beginning in December 2029.

Aubrey Rodriguez, a legislative advocate with American Civil Liberties Union California Action, an advocacy organization formed by the ACLU’s three affiliates in the state, said the bill would ask ordinary users, schools and businesses to accept a new layer of control based on software they still do not trust.

Rodriguez said the proposal risks creating “a permanent back door into the privacy of our own homes, ripe for exploitation.”

“Once this new infrastructure exists, it is a simple software update away from tracking political dissent or preventing 3-D printing designs deemed inappropriate,” Rodriguez said.

California has some of the nation’s toughest gun laws, but state lawmakers are concerned that a new technology is allowing criminals to obtain firearms by building them from scratch. By using 3-D printers, they warn, lawbreakers are able to make key components of untraceable “ghost guns” with the press of a button.

Ghost guns, which authorities say make it more difficult to investigate shootings because they lack serial numbers, have been a growing problem for law enforcement nationwide. According to federal data, the number of privately made firearms recovered in crimes surged from more than 1,600 in 2017 to nearly 27,500 in 2023. California leads the nation in recoveries over that period.

In response, legislators are seeking to mandate that all 3-D printers sold in the state come equipped with software that prohibits users from making triggers and other gun parts. A bill passed the Assembly in May and is advancing through the Senate.

But the proposal has drawn opposition from a diverse coalition, which includes civil liberties groups, tech companies and 3-D printing enthusiasts as well as Hollywood effects studios, who argue that “firearm blocking software” will also prohibit legitimate designs and expose makers to government or corporate surveillance.

Inside a San Fernando workshop, Samuel McBride makes movie monsters come to life for the camera. One of his latest creations, an animatronic hand, clutches when he pulls a trigger that he built using a 3-D printer.

McBride says the technology has transformed the work at Legacy Effects, where he is a lab manager, but he’s worried it will soon be off-limits because of a proposed change in California law.

McBride fears the law would interfere with the making of devices like the one that activates his lifelike hand.

“If I just took apart this trigger and put it on a printer, how is anyone, computer or human, going to tell me how I intend to use it?” he asked.

Backers of the proposed law say it has the potential to help save lives.

“As gun violence continues to devastate our communities, we cannot allow 3-D printing technology to become a new pipeline for untraceable weapons,” said Assemblymember Rebecca Bauer-Kahan, the bill’s author.

Critics of the proposed California law note that 3-D printed guns represent a small subset of ghost guns recovered by law enforcement at crime scenes. According to the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, most “privately made firearms” recovered by police are assembled from mail-order kits or unfinished parts rather than printed at home.

Jorge Perez of Monster City Studios holds a sculpture made with a large, industrial 3-D printer.

(Ronaldo Bolaños / Los Angeles Times)

“This fight is not over whether ghost guns are dangerous,” said David Tobin, an independent creator leading the coalition. “It is over whether the state can or should require a consumer tool to surveil a person’s designs before they are allowed to make something.”

Everytown for Gun Safety, a national nonprofit that advocates for gun control and has pushed for the passage of California’s bill, pointed to rising 3-D printed firearm recoveries across 20 major cities and warned that homemade plastic parts can help people bypass background checks or turn handguns into automatic weapons.

Krystal LoPilato, who advocates for policy at Everytown, said the group has successfully guided a similar bill through the New York state Legislature.

A handgun frame made using a 3-D printer is held for display at the office of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

(Alex Brandon / Associated Press)

LoPilato said the policy aims to be proactive, rather than allowing more violence to take place before regulating the problem. Opponents counter that California already bars unlawful firearm manufacturing with 3-D printers, and that ghost gun recoveries have declined since the state adopted a series of new laws and enforcement efforts.

A June 1 letter to lawmakers, signed by a group of 3-D printing companies, stagecraft and prop-making studios and industry stakeholders, argued that AB 2047 raises 1st Amendment concerns and would harm businesses. The letter was signed by a wide variety of companies and individuals, including Prusa Research, a prominent 3-D printer manufacturer.

“To an algorithm, a gun barrel and a piece of pipe are the same grooved cylinder,” Jakub Kmošek, head of public affairs at Prusa, said in a statement to The Times. “This bill will only make it harder to build, repair, experiment, and innovate in California.”

Alan Scott, Legacy Effects’ co-founder, said 3-D printing has become central to the company’s survival in an industry where budgets are tighter and deadlines are shorter.

“Everything’s just got to be done faster these days. You don’t get to reduce the quality. We couldn’t stay in business if we weren’t 3-D printing,” Scott said.

To solve this problem, Bauer-Kahan put an entertainment industry exception in the bill, exempting “printers manufactured for and sold exclusively to entertainment industry stagecraft and propmaking studios” from the software requirement.

McBride, Legacy’s 3-D lab manager, said those printers do not really exist.

Legacy uses the same general-purpose machines available to other businesses willing to invest in the equipment, and no printers are marketed exclusively for Hollywood, he said.

1

2

1. A 3-D printed sculpture concept at Monster City, a special effects studio in Santa Clarita. (Ronaldo Bolaños / Los Angeles Times) 2. 3-D printing advocate David Tobin showcases a robotics kit at Monster City. (Ronaldo Bolaños / Los Angeles Times)

Legacy also worries about privacy. Major studios require strict secrecy before a movie or show is released. To accommodate this, the company shares design files through encrypted servers and protected internal systems.

“We’ve invested hundreds of thousands of dollars to bring all that technology here under the umbrella of our NDAs and our IP protection,” McBride said.

Bauer-Kahan noted at a Senate hearing that she is working to address concerns raised by 3-D printing users and industries that rely on the technology.

Paul Powers, chief executive of Physna, a company whose technology could be used to block gun parts on 3-D printers, said the strongest criticisms of AB 2047 “misunderstand how the software works.”

“Something that vaguely looks like a gun part is not considered to be a match,” he said.

Powers also responded to surveillance concerns by clarifying that his company’s software only blocks the printer from making prohibited parts — it doesn’t flag them to authorities or log users’ intellectual property.

“There’s no communication with anyone; it doesn’t go anywhere,” he said.

But Marleen Vogelaar, chief executive of Thangs3D, a platform for independent creators to share and sell 3-D printable designs, said that answer does not resolve her broader concerns about how AB 2047 would work in practice.

“These databases will always lag behind innovation and can be easily circumvented and generate false positives that block legal designs and wrongly flag everyday makers,” she said at a Senate hearing this month. “The bill also creates serious privacy and security risks by giving third parties access to analyze designer’s files. That threatens intellectual property and adds digital surveillance in a state that values data privacy.”

If the bill passes, the state’s Department of Justice would publish a roster of compliant printers. Printers not on the list would be banned from sale or transfer in California beginning in December 2029.

Aubrey Rodriguez, a legislative advocate with American Civil Liberties Union California Action, an advocacy organization formed by the ACLU’s three affiliates in the state, said the bill would ask ordinary users, schools and businesses to accept a new layer of control based on software they still do not trust.

Rodriguez said the proposal risks creating “a permanent back door into the privacy of our own homes, ripe for exploitation.”

“Once this new infrastructure exists, it is a simple software update away from tracking political dissent or preventing 3-D printing designs deemed inappropriate,” Rodriguez said.

California has some of the nation’s toughest gun laws, but state lawmakers are concerned that a new technology is allowing criminals to obtain firearms by building them from scratch. By using 3-D printers, they warn, lawbreakers are able to make key components of untraceable “ghost guns” with the press of a button.

Ghost guns, which authorities say make it more difficult to investigate shootings because they lack serial numbers, have been a growing problem for law enforcement nationwide. According to federal data, the number of privately made firearms recovered in crimes surged from more than 1,600 in 2017 to nearly 27,500 in 2023. California leads the nation in recoveries over that period.

In response, legislators are seeking to mandate that all 3-D printers sold in the state come equipped with software that prohibits users from making triggers and other gun parts. A bill passed the Assembly in May and is advancing through the Senate.

But the proposal has drawn opposition from a diverse coalition, which includes civil liberties groups, tech companies and 3-D printing enthusiasts as well as Hollywood effects studios, who argue that “firearm blocking software” will also prohibit legitimate designs and expose makers to government or corporate surveillance.

Inside a San Fernando workshop, Samuel McBride makes movie monsters come to life for the camera. One of his latest creations, an animatronic hand, clutches when he pulls a trigger that he built using a 3-D printer.

McBride says the technology has transformed the work at Legacy Effects, where he is a lab manager, but he’s worried it will soon be off-limits because of a proposed change in California law.

McBride fears the law would interfere with the making of devices like the one that activates his lifelike hand.

“If I just took apart this trigger and put it on a printer, how is anyone, computer or human, going to tell me how I intend to use it?” he asked.

Backers of the proposed law say it has the potential to help save lives.

“As gun violence continues to devastate our communities, we cannot allow 3-D printing technology to become a new pipeline for untraceable weapons,” said Assemblymember Rebecca Bauer-Kahan, the bill’s author.

Critics of the proposed California law note that 3-D printed guns represent a small subset of ghost guns recovered by law enforcement at crime scenes. According to the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, most “privately made firearms” recovered by police are assembled from mail-order kits or unfinished parts rather than printed at home.

Jorge Perez of Monster City Studios holds a sculpture made with a large, industrial 3-D printer.

(Ronaldo Bolaños / Los Angeles Times)

“This fight is not over whether ghost guns are dangerous,” said David Tobin, an independent creator leading the coalition. “It is over whether the state can or should require a consumer tool to surveil a person’s designs before they are allowed to make something.”

Everytown for Gun Safety, a national nonprofit that advocates for gun control and has pushed for the passage of California’s bill, pointed to rising 3-D printed firearm recoveries across 20 major cities and warned that homemade plastic parts can help people bypass background checks or turn handguns into automatic weapons.

Krystal LoPilato, who advocates for policy at Everytown, said the group has successfully guided a similar bill through the New York state Legislature.

A handgun frame made using a 3-D printer is held for display at the office of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

(Alex Brandon / Associated Press)

LoPilato said the policy aims to be proactive, rather than allowing more violence to take place before regulating the problem. Opponents counter that California already bars unlawful firearm manufacturing with 3-D printers, and that ghost gun recoveries have declined since the state adopted a series of new laws and enforcement efforts.

A June 1 letter to lawmakers, signed by a group of 3-D printing companies, stagecraft and prop-making studios and industry stakeholders, argued that AB 2047 raises 1st Amendment concerns and would harm businesses. The letter was signed by a wide variety of companies and individuals, including Prusa Research, a prominent 3-D printer manufacturer.

“To an algorithm, a gun barrel and a piece of pipe are the same grooved cylinder,” Jakub Kmošek, head of public affairs at Prusa, said in a statement to The Times. “This bill will only make it harder to build, repair, experiment, and innovate in California.”

Alan Scott, Legacy Effects’ co-founder, said 3-D printing has become central to the company’s survival in an industry where budgets are tighter and deadlines are shorter.

“Everything’s just got to be done faster these days. You don’t get to reduce the quality. We couldn’t stay in business if we weren’t 3-D printing,” Scott said.

To solve this problem, Bauer-Kahan put an entertainment industry exception in the bill, exempting “printers manufactured for and sold exclusively to entertainment industry stagecraft and propmaking studios” from the software requirement.

McBride, Legacy’s 3-D lab manager, said those printers do not really exist.

Legacy uses the same general-purpose machines available to other businesses willing to invest in the equipment, and no printers are marketed exclusively for Hollywood, he said.

1

2

1. A 3-D printed sculpture concept at Monster City, a special effects studio in Santa Clarita. (Ronaldo Bolaños / Los Angeles Times) 2. 3-D printing advocate David Tobin showcases a robotics kit at Monster City. (Ronaldo Bolaños / Los Angeles Times)

Legacy also worries about privacy. Major studios require strict secrecy before a movie or show is released. To accommodate this, the company shares design files through encrypted servers and protected internal systems.

“We’ve invested hundreds of thousands of dollars to bring all that technology here under the umbrella of our NDAs and our IP protection,” McBride said.

Bauer-Kahan noted at a Senate hearing that she is working to address concerns raised by 3-D printing users and industries that rely on the technology.

Paul Powers, chief executive of Physna, a company whose technology could be used to block gun parts on 3-D printers, said the strongest criticisms of AB 2047 “misunderstand how the software works.”

“Something that vaguely looks like a gun part is not considered to be a match,” he said.

Powers also responded to surveillance concerns by clarifying that his company’s software only blocks the printer from making prohibited parts — it doesn’t flag them to authorities or log users’ intellectual property.

“There’s no communication with anyone; it doesn’t go anywhere,” he said.

But Marleen Vogelaar, chief executive of Thangs3D, a platform for independent creators to share and sell 3-D printable designs, said that answer does not resolve her broader concerns about how AB 2047 would work in practice.

“These databases will always lag behind innovation and can be easily circumvented and generate false positives that block legal designs and wrongly flag everyday makers,” she said at a Senate hearing this month. “The bill also creates serious privacy and security risks by giving third parties access to analyze designer’s files. That threatens intellectual property and adds digital surveillance in a state that values data privacy.”

If the bill passes, the state’s Department of Justice would publish a roster of compliant printers. Printers not on the list would be banned from sale or transfer in California beginning in December 2029.

Aubrey Rodriguez, a legislative advocate with American Civil Liberties Union California Action, an advocacy organization formed by the ACLU’s three affiliates in the state, said the bill would ask ordinary users, schools and businesses to accept a new layer of control based on software they still do not trust.

Rodriguez said the proposal risks creating “a permanent back door into the privacy of our own homes, ripe for exploitation.”

“Once this new infrastructure exists, it is a simple software update away from tracking political dissent or preventing 3-D printing designs deemed inappropriate,” Rodriguez said.