3D printing, or additive manufacturing, builds three-dimensional objects from digital designs. It powers prototyping, custom parts, and, controversially, ghost gun debates as tech evolves.
New York and California are pushing legislation to require firearm-blocking technology in 3D-printers to detect gun designs before printing. Critics warn it might not work and could raise privacy and rights concerns. The effort builds on a surge in privately made guns; a study group will assess feasibility before any mandate takes effect.