ICYMI: SFC's Comprehensive Response to Bambu's AGPLv3 Violations
Software Freedom Conservancy
3dprint at sfconservancy.org
Wed Jun 3 20:36:27 UTC 2026
SFC's Comprehensive Response to Bambu's AGPLv3 Violations
URL: https://sfconservancy.org/news/2026/may/18/bambu-studio-3d-printer-agpl-violation-response/
Fediverse: https://social.sfconservancy.org/objects/b0db3c47-3c81-4213-8549-10b37d6f57a1
Notable Third-Party News Coverage:
The Verge: https://www.theverge.com/tech/931532/bambu-agpl-pawel-jarczak-open-source-threat-dmca-github
LWN: https://lwn.net/Articles/1074286/
Tom's Hardware: https://www.tomshardware.com/3d-printing/open-source-non-profit-claims-bambu-lab-violated-license-move-follows-cease-and-desist-demand-on-orcaslicer-fork-that-restored-cloud-printing-features-without-using-bambu-connect
All3DP: https://all3dp.com/4/bambu-labs-bind-open-source-license-fight-has-a-new-and-very-serious-opponent/
Full announcement follows:
Multi-pronged Approach Will Help 3D Printer Users Quickly
while Seeking Optimal Long-Term Solutions
Software Freedom Conservancy (“SFC”) recently announced 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.
First, 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 years² 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 AGPLv3³ by combining Bambu Studio with a proprietary
library — which they distribute to the user via an interactive prompt in
the UI.
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.
Additional Violation Via Bambu's Aggressive, “Chilling Effect” Recent
Actions
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 OrcaSlicer with these
changes from Github. Bambu falsely claims that⁴ 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)⁵. This is an
understandable response; anyone would be concerned when a powerful
company sends aggressive emails.
SFC's Comprehensive Approach to Address These Violations
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.
1. SFC launches today our baltobu project⁶. This project contains
repositories as follows:
(a) baltobu's reverse-networking repository hosts a project to
reverse-engineer⁷ libbambu_networking.so, bambu_networking.dll, and
libbambu_networking.dylib.
We also have encouraged volunteers in our Use the Source⁸ community
to participate⁹⁻¹⁰ in this process.
As we have previously explained: Object Code combined with AGPLv3'd
software must also be licensed under AGPLv3¹¹! 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.
(b) baltobu's orca-slicer-for-bambu repository¹² 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 protection¹³, and
SFC does our best to insert ourselves should Bambu make legal
threats to any of our volunteers.
(c) baltobu's viscose repository¹⁴ 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.
2. SFC will continue as a watchdog for any further Bambu Lab violations.
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.
3. SFC will launch a standing committee to discuss software freedom and
rights in the 3D printer community.
Details on this committee will be forthcoming later this month.
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.
Volunteer Can Help Now!
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 visit https://f.sfconservancy.org/baltobu
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 at sfconservancy.org> (and by replying to this
email).
SFC Fundraiser to Support this Effort Has Reached Halfway Point!
As of late last night (TUE 2026-06-02), our fundraiser — with a target
goal of US$250,007 — passed its halfway point! The fundraiser will
continue until July 17ᵗʰ! Details and donation information are at the
top of SFC's website.
Thanks to All Who Have Already Helped on this Matter
We are grateful for efforts of everyone who who have helped so much to
get this started! In particular:
• Thanks so much to Paweł Jarczak who drew our attention to Bambu
Lab's ongoing AGPLv3 violations! Paweł did what all software
developers are allowed to do under AGPLv3: change the source code to
do something interesting! Paweł did not deserve Bambu Lab's bad
treatment, and we look forward to collaborating with Paweł.
• We also thank b3nsn0w — who has done substantial additional research
about the situation with Bambu Lab, and has been a voice for the
AGPLv3 for more than a year regarding the dynamically linked
libraries violation.
Thanks also to FULU for taking a stand and drawing attention to this
issue.
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Footnote:
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.
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References:
² https://github.com/bambulab/BambuStudio/blob/e8c7dc1b84f5e3816238e070e04eeeb67cd92783/README.md?plain=1#L42-L49
³ https://github.com/bambulab/BambuStudio/blame/e8c7dc1b84f5e3816238e070e04eeeb67cd92783/README.md#L51-L52
⁴ https://blog.bambulab.com/setting-the-record-straight-on-cloud-access-and-community/
⁵ https://github.com/jarczakpawel/OrcaSlicer-bambulab/commit/25bbf7fd65963b6b787b36025cf5f8f993a28d43#diff-b335630551682c19a781afebcf4d07bf978fb1f8ac04c6bf87428ed5106870f5R3-R7
⁶ https://f.sfconservancy.org/baltobu
⁷ https://f.sfconservancy.org/baltobu/reverse-networking
⁸ https://sfconservancy.org/usethesource
⁹ https://sfconservancy.org/usethesource/candidate/bambu-studio-linux-240/
¹⁰ https://sfconservancy.org/usethesource/candidate/bambu-studio-windows-25066/
¹¹ https://sfconservancy.org/blog/2026/may/17/incomplete-corresponding-source-code-copyleft-agpl/#object-code-also-copylefted
¹² https://f.sfconservancy.org/baltobu/orca-slicer-for-bambu
¹³ https://sfconservancy.org/projects/services/#some-liability-protection
¹⁴ https://f.sfconservancy.org/baltobu/viscose
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