The open-source OpenCAL project has released Tomo, a standalone application meant to do for volumetric additive manufacturing (VAM) what slicers like PrusaSlicer did for FDM: take a process that once demanded serious technical fluency and reduce it to a workflow a hobbyist can actually finish. Tomo is the software half of a broader summer 2026 push from OpenCAL that also includes new V2 hardware and an in-progress resin collaboration with Formlabs — together aimed at pulling computed axial lithography out of the research lab and onto the hobbyist's bench.
If you haven't been tracking VAM, the pitch is genuinely strange the first time you hear it: instead of building an object layer by layer, a volumetric printer spins a vial of liquid photopolymer resin while a projector fires shifting light patterns through it from multiple angles. Where the accumulated light dose crosses the resin's cure threshold, the whole object solidifies essentially at once — not layer by layer, but as a coherent 3D shape emerging from a rotating cylinder of liquid. The underlying technique, computed axial lithography (CAL), was invented at UC Berkeley in 2017, and the OpenCAL project has spent the years since trying to turn that lab technique into something buildable outside a university.
From Berkeley Bench to Afternoon Build
According to a July 7, 2026 report on Hackaday, OpenCAL's hardware has gone through three distinct eras. The original 2019 version, descended directly from the Berkeley lab setup, was — in Hackaday's words — "functionally practical for only big budget research," too expensive and complicated for a hobbyist with a day job to realistically build. A 2025 iteration shown at Open Sauce marked a real inflection point, swapping in a consumer projector and common hobbyist electronics and proving that a CAL rig could be built from parts a maker could actually source.
That trajectory continues with OpenCAL V2, which according to the project's own documentation is an open-source CAL platform built from gathered components and 3D-printed parts, and which "can be assembled in an afternoon." That's a notable claim for a printing method that, four years ago, was confined to optics benches, with a build process explicitly scoped for a single afternoon rather than a lab-supported project.
What Tomo Actually Does
Hardware that's easy to assemble is only half the problem, though — and it's arguably not the harder half. VAM's real barrier has always been the software: calculating exactly how much light dose to project, from which angles, and in what rotational sequence, so that a solid object forms in the right place inside the vial without over- or under-curing the surrounding resin. Get the dosage math wrong and you get a malformed blob or a vial of unset liquid. That calculation is the job of VAMToolbox, also known as Tomo — the driving software behind OpenCAL's printers. Per the project's documentation, Tomo computes the light-dosage requirements needed for a part to solidify correctly as the vial spins, essentially playing the role a slicer plays for FDM or resin-vat printing, but for a fundamentally different physical process. Historically, that software layer has been the sticking point. As Hackaday describes it, past VAM tooling suffered "from being undocumented to being complicated for anyone without comfort in command line," meaning makers who could physically build a CAL rig were then stuck wrestling with scripts just to generate a print job. Tomo is built to close that gap — the OpenCAL team's stated goal, per Hackaday, is to let users run "an OpenCAL printer with little thought or expertise, or ideally any other type of VAM printer," turning what used to be a research-software exercise into something closer to loading an STL and hitting print.
Minutes, Not Hours
The headline advantage of volumetric printing remains speed. Because the entire object cures effectively at once rather than accumulating one thin layer at a time, OpenCAL's documentation describes inch-scale objects forming in minutes — faster than a traditional layer-by-layer 3D printer could manage even a fraction of the same part. OpenCAL's own documentation notes there are "no layers and no support structures" in the finished process, meaning there's no layer-adhesion question to worry about and no support structures needed to keep overhangs from sagging before the next layer bonds, since the object solidifies as a single continuous mass suspended in resin. The tradeoff, as with most emerging processes, is scale and material range: CAL is currently suited to inch-scale objects rather than large-format prints, and it depends on resins formulated to respond correctly to the dosage patterns Tomo calculates. That's where the talks with Formlabs come in. Per Hackaday's reporting, the OpenCAL team and Formlabs are working out an agreement for production of a specialized resin — a collaboration that, once finalized, would pair OpenCAL's open hardware and software with a supply chain from a company with deep experience formulating photopolymers at scale.
What It Means for Makers
For hobbyists who've watched volumetric printing from a distance — impressive demo videos, inaccessible hardware — this summer's releases are the clearest signal yet that the barrier to entry is dropping rather than just getting better PR. A frame built largely from 3D-printed parts that assembles in an afternoon, software that doesn't require reading through a GitHub wiki to generate a valid dose pattern, and a resin supply deal in the works all point toward VAM becoming something you could plausibly build over a weekend rather than something requiring a university lab. That said, makers should temper expectations about what "easy" means here. Tomo lowers the software barrier, but VAM printers still involve calibrating optics, aligning a rotating vial, and working with resin chemistry tuned specifically for this process — none of which is trivial even with better tooling. Unlike FDM or standard resin printing, there isn't yet a mature ecosystem of tested settings profiles or off-the-shelf consumables; OpenCAL's own support channel is still primarily community documentation and a Discord server rather than a commercial support line. Still, the direction is unmistakable. VAM has moved from a Berkeley optics bench, to a hobbyist rig shown off at Open Sauce, to an afternoon build with a slicer-equivalent app and a resin deal in the works — in less than a decade. Whether Tomo actually makes volumetric printing "as easy as slicing an STL" is something only makers who build a V2 rig will be able to answer, but the software gap that has held VAM back the longest finally has a dedicated tool aimed squarely at it.
