Bambu Lab Sued an Open Source Dev. Now They're Accused of Violating AGPL.

Bambu Lab gets called the Apple of 3D printing for a reason. Slick UI, blazing print speeds, and an out-of-the-box experience that made the old RepRap crowd look like hobbyist tinkerers. But the company is now the most disliked name in the open source 3D printing world — and this week, the accusations turned back on Bambu itself.

How Bambu Lab Burned Its Goodwill

A quick recap for readers outside the 3D printing scene. Bambu Lab is a Chinese manufacturer that, with its X1, P1, and A1 lines, basically rewrote the rules for desktop 3D printers. The pitch: plug it in, hit print, get good results. No bed leveling rituals, no firmware compiling.

That was the upside. The downside started in 2024, when Bambu pushed its firmware toward mandatory cloud connectivity. Owners who wanted local control of their own hardware got increasingly squeezed. The company also walked a strange line with OrcaSlicer — a community fork of its own slicer — alternately cooperating and freezing it out.

The X1Plus Lawsuit

The breaking point was X1Plus. A community project, X1Plus was custom firmware that gave users deeper control of their X1-series printers. Tinkering on hardware you own — exactly what makes the open source 3D printing scene work. Bambu Lab saw it as a threat and went after the developers legally.

For the community, this wasn’t a niche IP dispute. It was about whether you actually own the printer sitting on your desk. r/3Dprinting and r/BambuLab pivoted hard. The anti-Bambu sentiment that crystallized in that period hasn’t faded. Hacker News threads from the time read like an obituary for the company’s open source credibility.

The Twist: Bambu’s Own License Problem

Here’s where it gets uncomfortable. Bambu Studio — the company’s slicer, the software it ships with every printer — is a fork of PrusaSlicer. PrusaSlicer is developed by Prusa Research in the Czech Republic and released under the AGPL v3.

AGPL is the strict cousin of the GPL. Standard GPL says: if you distribute modified code, publish your source. AGPL goes further: if you provide network services using the code, you also have to publish your modifications. Forking PrusaSlicer means you owe the public every change you made, including cloud-side glue code.

The allegation now circulating is that Bambu Lab hasn’t been fully releasing source for parts of Bambu Studio — particularly the cloud integration layer and certain internal modules. PrusaSlicer contributors and license experts looking at the situation are calling it a clear AGPL violation.

The Hypocrisy Problem

This is why the word “boomerang” keeps showing up in community discussions. Bambu Lab leaned on its own intellectual property rights to pressure independent developers off their own hardware. Meanwhile, the company’s flagship software product is literally built on top of someone else’s open source code.

A widely shared YouTube video titled “The Apple of 3D Printing Has a Dark Secret” sums it up bluntly: take the benefits of open source, skip the obligations. And the more you look at it, the more this stops looking like an oversight and starts looking like a business model. The closed-cloud strategy and the AGPL-derived slicer aren’t separate problems — they’re the same problem.

The Stakes of Copyleft

AGPL isn’t a polite request. It’s a binding license, and violations don’t just trigger a lawsuit risk — they automatically terminate the license itself. If a violation is confirmed and not cured, Bambu Lab arguably loses the right to use PrusaSlicer-derived code at all. That would be an existential issue for Bambu Studio.

Will Prusa Research actually sue? Probably not soon. The two companies are already locked in brutal market competition, and US/EU-style copyleft litigation is slow and expensive. But the optics damage is already done. Companies that treat open source as a free buffet eventually trip over their own contradictions.

If you’re a Bambu Lab owner, does any of this change your next purchase — or is “the prints look great” still the only line that matters? The community has been wrestling with that question for a year. This week it got harder to dodge.