Comprehensive Response to Bambu's AGPLv3 Violations - Software Freedom Conservancy
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Comprehensive Response to Bambu's AGPLv3 Violations
Multi-pronged Approach Will Help Users Quickly<br>while Seeking Optimal Long-Term Solutions
May 18, 2026
Software Freedom Conservancy (“SFC”) announces a new<br>initiative regarding the software right to repair for users and consumers<br>of 3D printers manufactured by Bambu Lab. After recent news of violations of the Affero General Public License,<br>version 3 (“AGPLv3”), SFC staff began a<br>comprehensive AGPLv3 compliance investigation of both the userspace<br>software and firmware on Bambu's devices. While the investigation is<br>ongoing, two specific AGPLv3 violations have been confirmed.
libbambu_networking Violation Confirmed
First, Bambu does not provide the complete,<br>Corresponding Source Code (“CCS”) for their Slicer<br>software. (The Slicer is used in 3D printing to take a digital design<br>model (i.e., the STL file) and “slice” that file<br>into many horizontal 2D layers for transmission to the printer itself.)<br>Bambu has<br>publicly stated for four years that Bambu's slicer (called<br>“Bambu Studio”) is a modified version of their competitor's<br>AGPLv3'd slicer (“PrusaSlicer”). (PrusaSlicer — in turn — is a modified version of<br>“Slic3r” — originally authored by Alessandro Ranellucci.) While<br>some source code for Bambu Studio can be found on<br>Bambu's Github organizational<br>account, Bambu<br>(in effect) admits publicly that they have violated the AGPLv3 by combining Bambu Studio with a<br>proprietary library — which they distribute to the user via an<br>interactive prompt in the UI.
The specific clauses of AGPLv3 that Bambu has violated are quoted<br>below1:
You may convey a covered work in Object Code form … provided that you<br>also convey the machine-readable Corresponding Source under the terms of this<br>License … You must license the entire work, as a whole, under this<br>License to anyone who comes into possession of a copy. …
The “Source Code” for a work means the preferred form of the<br>work for making modifications to it. “Object Code” means any<br>non-source form of a work.
The “Corresponding Source” for a work in Object Code form<br>means all the Source Code needed to generate, install, and (for an executable<br>work) run the Object Code and to Modify the work, including scripts to<br>control those activities. … For example, Corresponding Source includes<br>interface definition files associated with source files for the work, and the<br>Source Code for shared libraries and dynamically linked subprograms that the<br>work is specifically designed to require, such as by intimate data<br>communication or control flow between those subprograms and other parts of<br>the work.
— AGPLv3§6¶1, §5(c), §1¶1,4
As such, Bambu's failure to provide<br>CCS and<br>Installation Information for the libraries known<br>as libbambu_networking.so, bambu_networking.dll,<br>and libbambu_networking.dylib constitutes an egregious and<br>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<br>Bambu violated AGPLv3. A software developer and Bambu Lab user (Paweł<br>Jarczak) released another mechanism to integrate with Bambu Studio's server<br>side components that did not require replacing or modifying the dynamically linked<br>libraries. Instead, Paweł made changes to a different AGPLv3'd slicer (Orca Slicer) by<br>merely examining the (incomplete) source code for Bambu Studio. Those Orca Slicer modifications<br>allowed users to replace Bambu Studio and instead combine Orca Slicer via intimate data<br>communication with Bambu Studio's currently-source-unavailable parts that run on<br>Bambu Lab's servers.
Bambu demanded that Paweł remove the fork of OracSlicer with these changes<br>from Github. Bambu falsely claims<br>that their terms of service override the AGPLv3 (along with other specious<br>claims). Bambu's scare tactics against Paweł constitute a violation of<br>AGPLv3§10¶3 — which states the matter quite simply: You may not<br>impose any further restrictions on the exercise of the rights granted or<br>affirmed under this License.
Paweł removed the Orca Slicer fork<br>(under protest). This is an understandable response;<br>anyone would be concerned when a powerful company sends aggressive<br>emails.
SFC's Comprehensive Approach to Address These Violations
Bambu has behaved...