OpenCAL Brings Layerless Volumetric 3D Printing to DIY Makers
3D PrintingStandard 3D printers build objects one layer at a time. OpenCAL prints the entire object simultaneously — in about three minutes — from a rotating vial of resin.
What Happened
OpenCAL is an open-source implementation of computed axial lithography (CAL), a volumetric additive manufacturing technique originally developed at UC Berkeley. The DIY project uses a rotating vial of photosensitive resin and a DLP projector to cure objects in three dimensions at once rather than building them sequentially layer by layer.
The physics work on tomographic reconstruction logic: a sequence of precisely calculated projection images is aimed through the rotating vial. Where enough light accumulates at any point in the volume, the resin solidifies. The VAMToolbox software computes dosage maps so only the regions meant to form the part receive a solidifying light dose. The result: the object forms everywhere simultaneously rather than growing upward from a build plate.
A documented demonstration produced two small geometric objects in approximately three minutes using a 30mm diameter vial.
Why It Matters
The layer-by-layer constraint isn’t only a speed issue — it’s a geometry issue. Traditional resin and FDM printing require support structures for overhangs and bridges, which consume material, extend print time, and leave marks requiring cleanup. In CAL printing, because the object forms simultaneously throughout the volume, overhangs simply exist without needing support.
For the maker community, the significant development is access. CAL has existed as an academic research technique since 2019; OpenCAL is the first version buildable from off-the-shelf components: a Raspberry Pi 5, a 1080p DLP projector, a stepper motor, rotary stage, and standard hardware. The compute and optics are within reach of any maker willing to build and calibrate the rig.
The technique also enables embedded materials: objects can be fabricated with items inserted directly in the resin, enabling novel assembly approaches that layer-based methods can’t achieve without post-print assembly steps.
The So What
OpenCAL is explicitly at proof-of-concept stage — the documentation is clear that failed prints will be common, calibration is demanding, and parts are undercured compared to traditional resin output. This is not a plug-and-print system. But it’s the first time CAL printing has been accessible outside a research lab, and the technique’s core advantages — speed, support-free geometry, embedded materials — are real. Makers with resin printing experience and a tolerance for calibration work should treat this as early access to a technique that will likely matter in desktop fabrication over the next decade.
Source: Make:
Content created with AI assistance and reviewed for accuracy.
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