Berkeley open-sources a volumetric 3D printer; parts cost about $1,638

A replica of Rodin's The Thinker can now take shape in 90 seconds, with no layers, no support structures and no moving print head. That is the reference part in the OpenCAL paper, and the printer is now released for anyone who wants to build one. UC Berkeley has released OpenCAL as a build-it-yourself volumetric 3D printer, with free software, public drawings and a published resin recipe.

The method behind it is unusual. A projector beams a rapidly changing sequence of computed light patterns into a rotating vial of resin, and the resin solidifies wherever the total light dose crosses a threshold. The software works like a CT scan in reverse: where a medical scanner rebuilds an image from X-ray projections, the software calculates the projections needed to rebuild a physical object out of light. The whole object forms at once, in one to two minutes, instead of being stacked slice by slice. Taylor Waddell led the project, which took two years and more than 40 contributors, most of them Berkeley students.

The obstacle was the chemistry. Until now, anyone building a volumetric printer at home had to mix the resin by hand from laboratory chemicals. Formlabs, the Somerville, Massachusetts maker of professional resin printers, now produces the Berkeley formulation at production scale as OpenCAL Resin, in 1-litre bottles. Prusa Research, founded in Prague in 2012, sells it in the United States for $119.99 a bottle, and hosts the printable parts on its Printables community. The hardware is released under Prusa's Open Community License, which guarantees the right to build, modify, repair and share the design. The recipe stays public for labs that prefer to mix their own.

For a researcher, a maker or a teacher, the change is practical. The bill of materials comes to about $1,638 at June 2026 prices, and one person can assemble the machine in five to six hours once the frame parts are printed. Print preparation runs on Tomo, a free Windows application that turns a standard 3D model file into a print sequence without any coding. Schools can run the machines for classroom and capstone projects; MIT, Purdue, Lawrence Livermore and NIST already have them running or under construction. Berkeley plans a one-day build workshop in February 2027.

The limits are real. Volumetric printing is still a research process, not an industrial one, and the figures for cost and speed come from the designers and the paper, not from independent tests across many machines. What the open release changes is who can find out: a group without access to a CAL lab can now build one, modify it and report back, which is how the earlier desktop printers spread to hobbyist workbenches.