May 18, 2026
Software Freedom Conservancy (“SFC”) announces a new initiative regarding the software right to repair for users and consumers of 3D printers manufactured by Bambu Lab. After recent news of violations of the Affero General Public License, version 3 (“AGPLv3”), SFC staff began a comprehensive AGPLv3 compliance investigation of both the userspace software and firmware on Bambu's devices. While the investigation is ongoing, two specific AGPLv3 violations have been confirmed.
libbambu_networking Violation ConfirmedFirst, Bambu does not provide the complete,
Corresponding Source Code (“CCS”) for their Slicer
software. (The Slicer is used in 3D printing to take a digital design
model (i.e., the STL file) and “slice” that file
into many horizontal 2D layers for transmission to the printer itself.)
Bambu has
publicly stated for four years that Bambu's slicer (called
“Bambu Studio”) is a modified version of their competitor's
AGPLv3'd slicer (“PrusaSlicer”). (PrusaSlicer — in turn — is a modified version of
“Slic3r” — originally authored by Alessandro Ranellucci.) While
some source code for Bambu Studio can be found on
Bambu's Github organizational
account, Bambu
(in effect) admits publicly that they have violated the AGPLv3 by combining Bambu Studio with a
proprietary library — which they distribute to the user via an
interactive prompt in the UI.
The specific clauses of AGPLv3 that Bambu has violated are quoted below1:
You may convey a covered work in Object Code form … provided that you also convey the machine-readable Corresponding Source under the terms of this License … You must license the entire work, as a whole, under this License to anyone who comes into possession of a copy. …
The “Source Code” for a work means the preferred form of the work for making modifications to it. “Object Code” means any non-source form of a work.
The “Corresponding Source” for a work in Object Code form means all the Source Code needed to generate, install, and (for an executable work) run the Object Code and to Modify the work, including scripts to control those activities. … For example, Corresponding Source includes interface definition files associated with source files for the work, and the Source Code for shared libraries and dynamically linked subprograms that the work is specifically designed to require, such as by intimate data communication or control flow between those subprograms and other parts of the work.
— AGPLv3§6¶1, §5(c), §1¶1,4
As such, Bambu's failure to provide
CCS and
Installation Information for the libraries known
as libbambu_networking.so, bambu_networking.dll,
and libbambu_networking.dylib constitutes an egregious and
ongoing violation of AGPLv3.
Keeping their networking library proprietary is not the only way that Bambu violated AGPLv3. A software developer and Bambu Lab user (Paweł Jarczak) released another mechanism to integrate with Bambu Studio's server side components that did not require replacing or modifying the dynamically linked libraries. Instead, Paweł made changes to a different AGPLv3'd slicer (Orca Slicer) by merely examining the (incomplete) source code for Bambu Studio. Those Orca Slicer modifications allowed users to replace Bambu Studio and instead combine Orca Slicer via intimate data communication with Bambu Studio's currently-source-unavailable parts that run on Bambu Lab's servers.
Bambu demanded that Paweł remove the fork of OracSlicer with these changes
from Github. Bambu falsely claims
that their terms of service override the AGPLv3 (along with other specious
claims). Bambu's scare tactics against Paweł constitute a violation of
AGPLv3§10¶3 — which states the matter quite simply: You may not
impose any further restrictions on the exercise of the rights granted or
affirmed under this License
.
Paweł removed the Orca Slicer fork (under protest). This is an understandable response; anyone would be concerned when a powerful company sends aggressive emails.
Bambu has behaved badly for years and made multiple, provably false public statements regarding the AGPLv3 and its requirements. The recent aggressive behavior toward Paweł Jarczak was a last straw for us: we have decided to launch a multi-pronged effort that will assist consumers and users in the short-term, and also work toward a long-term strategy to improve the software right to repair for all 3D printer consumers.
reverse-networking
repository hosts a project to
reverse-engineer libbambu_networking.so, bambu_networking.dll,
and libbambu_networking.dylib.
We also have encouraged volunteers in our Use the Source community to participate2, 3 in this process.
As we have previously explained: Object Code combined with AGPLv3'd software must also be licensed under AGPLv3! As such, these Object Code libraries are governed by the AGPLv3. SFC and our volunteers are within our rights to reverse-engineer these libraries for the purpose of creating our own Source Code that can function as a drop-in replacement in Bambu Studio.
If Bambu Studio were not known to be a strident long-time AGPLv3 violator, we would not begin with this approach, but we believe the reverse-engineering effort will yield results more quickly than legal action possibly can.
orca-slicer-for-bambu
repository will build on Paweł's work to become the canonical repository for
maintaining and improving the Orca Slicer fork that Paweł originally
published.
SFC does not fear Bambu's aggression. We welcome volunteers to join us in maintaining an OrcaStudio fork that works with Bambu's 3D printers. Volunteer contributors working on SFC's behalf have some amount of personal liability protection, and SFC does our best to insert ourselves should Bambu make legal threats to any of our volunteers.
viscose
repository seeks to maintain an active fork of Bambu Studio itself.
This project will seek to take the best of any discoveries from the two aforementioned initiatives and work toward a replacement for Bambu Studio that works better for consumers who own Bambu 3D printers.
Our staff spent the last week investigating the violations discussed here, but we will not stop there! We normally do not actively look for violations. However, in this case, SFC will watch Bambu Lab closely and continue to investigate — regularly looking for any potential violations of copyleft licenses.
Details on this committee will be forthcoming in June 2026. Generally speaking, this committee will bring together 3D printer manufacturers, users, consumers, copyleft licensing experts, and software freedom activists to meet monthly to communicate about any new issues or concerns that arise regarding the software right to repair for 3D printers and accompanying software, and to make action plans to address those issues.
The SFC welcomes volunteers to join these efforts immediately; we will need your help! We specifically welcome as our first volunteer Paweł Jarczak himself! Paweł's work has been instrumental in investigating Bambu's various AGPLv3 violations. Paweł has agreed to collaborate with SFC on the efforts we begin today.
If you would also like to help with any of the technical work going on in our baltobu project, please follow this link for information on how to request an account on our Forgejo instance. If you're interested in helping on any of the other initiatives above, please email us at <3dprint@sfconservancy.org>.
We also launch today a fundraiser with a target goal of US$250,007! This fundraiser will last for two months. All newly initiated Sustainer contributions and general donations to SFC will be earmarked for our software right to repair efforts. If we reach our ambitious fundraising goal, we'll immediately begin a search to hire an employee to head the efforts described herein — including coordination of volunteer contributors and strategic planning to improve the software right to repair for 3D printers. If we don't reach the goal, we will route the funds to (a) fund existing staff's time to focus on this project and (b) work on related software right to repair efforts.
We are grateful for efforts of everyone who who have helped so much to get this started! In particular:
1 The order of appearance of clauses in AGPLv3's text have been rearranged here for readability, and all defined terms have been herein capitalized for emphasis.