Simplified Projector Initiated Fabrication
Prusa democratized FDM. Bambu Labs perfected it. SPIF 1.0 is the opening move of the next era, taking volumetric fabrication out of the lab and putting it in the garage.
SPIF 1.0 runs on commercially available SLA resin — no exotic photopolymers, no unique resin compositions. The resin that doesn't cure stays liquid and is fully recyclable back into the vat.
Volumetric printing encodes the entire object in a single rotation sequence. As the technology matures, print times measured in minutes — not hours — become the baseline, not the exception.
The entire SPIF 1.0 prototype was researched and built for under $1,000. The goal is a consumer product at a price point that competes with today's desktop resin printers — not tomorrow's industrial machines.
FDM, SLA, SLS — these are all variations on the same theme. SPIF introduces a fundamentally different physics. Not an iteration. A new column in the table.
OpenCAL is the open-source projection control software at the heart of axial lithography workflows. All prior implementations ran on Windows or Linux. SPIF 1.0 achieved the first documented macOS integration.
Prior volumetric research uses custom-formulated resins with tightly controlled photoinitiator concentrations. SPIF 1.0 demonstrates that off-the-shelf desktop SLA resin can be adapted to axial lithography, removing a major barrier to accessible volumetric fabrication.
Projection hardware, rotation platform, and custom software systems; the complete SPIF 1.0 development cycle ran under $1,000, with a final bill-of-materials around $200. This sets a concrete cost floor for entry-level volumetric fabrication, and anchors a viable consumer pricing target.
Traditional resin printing cures one thin slice at a time, stacking them like pages in a book. Axial lithography throws out the book entirely.
A cylindrical container of photo-curable resin rotates continuously from a motorized arm. Unlike standard printing, the resin isn't waiting to be sliced, rather, it works with the projection to build in three dimensions.
A projector fires carefully computed 2D images, synchronized to the rotation angle of the vat. In essence, a reverse CT scan, each frame projects the correct light-depth map of the desired model at that respective angle.
As the vat rotates through a full revolution, each point in the resin accumulates light dose from multiple angles. Where the total exposure exceeds the cure threshold, the resin can solidify.
Due to the geometry curing quickly, in a viscous medium, and because of the projections, it can cure all at once, in place, and without supports, almost appearing from nowhere, just floating in the resin.
Science is not a destination. It's a series of increasingly precise approximations.
SPIF 1.0 is a functioning volumetric 3D printer,readily and consistently producing objects. The fundamental principle — light accumulation curing a 3D volume — works. Every run produces an object.
Current prints produce what we call "blobified geometries" from static, geometric projections. These are objects with the correct volumetric character, though they do not yet have the sharp boundaries of the target model. This is a result of known factors and optimization points: projection & index-match optimization, synchronization tolerance, and rotation precision. Each is addressable.
Active variables being explored: temperature, intenstiy, viscosity, componentry.
SPIF 1.0 is evolving. Follow along as the research advances, fidelity improves, and the path to a consumer product takes shape.
Researched, Developed, Designed, and Built by Brett Rabbiner · SPIF 1.0 · November 2025 - Present