An ongoing 3D-printer AGPL violation

一起持续中的 3D 打印机 AGPL 违规事件

At FOSSY 2026, several people from the Software Freedom Conservancy (SFC), which organizes the conference, gave a presentation about an ongoing violation of the Affero General Public License version 3 (AGPLv3). Bradley Kühn, Karen Sandler, and Denver Gingerich spoke about different aspects of the violation, which is in regard to 3D-printer software from Bambu Lab, and what is being done to try to provide users with alternatives. One aspect that is particularly interesting is that the circumvention that the company is employing is precisely what the AGPL was written to prevent.

在 2026 年的 FOSSY 大会上，负责组织该会议的软件自由保护协会（SFC）的几位成员发表了一场演讲，讨论了一起正在发生的针对 Affero 通用公共许可证第 3 版（AGPLv3）的违规事件。Bradley Kühn、Karen Sandler 和 Denver Gingerich 分别从不同角度阐述了这起涉及 Bambu Lab（拓竹科技）3D 打印机软件的违规行为，以及目前为向用户提供替代方案所做的努力。其中一个特别值得关注的点是，该公司所采用的规避手段，恰恰正是 AGPL 协议旨在防止的行为。

Kühn began the session by noting that he has been an activist in the free and open-source software (FOSS) communities for over 30 years and that “this moment in history […] has more activism opportunities than I have seen in my career”. In the past, he and his colleagues have been triaging disasters of various sorts but over the past six to eight months they have been triaging opportunities instead. Sandler added that the opportunities being offered are difficult; “it’s not like people are saying ‘would you like this money or that money?’”. The opportunities he is describing are not really about money, Kühn said, but provide ways “for activists to get stuff done and to engage people”. Over the past six months or so, SFC has successfully engaged with “an entire community of enthusiasts”, which only had a passing familiarity with FOSS, on a multitude of freedom-centric topics: “free software, free culture, free creation”. That is exciting, but he was getting ahead of himself because that is where the story ends, so he wanted to go back to the beginning.

Kühn 在会议开始时指出，他作为自由及开源软件（FOSS）社区的活动家已有 30 多年，并表示“历史上的这一刻……比我职业生涯中见过的任何时候都有更多的行动机会”。过去，他和同事们一直在处理各种灾难，但在过去的六到八个月里，他们转而开始处理这些“机会”。Sandler 补充说，这些机会充满挑战；“这并不是说有人在问‘你想要这笔钱还是那笔钱？’”。Kühn 表示，他所描述的机会并非关乎金钱，而是为“活动家们完成工作并与人们互动”提供了途径。在过去六个月左右的时间里，SFC 成功地与“整个爱好者社区”进行了接触，这些爱好者此前对 FOSS 仅有浅显的了解，但现在已深入探讨了诸多以自由为中心的话题：“自由软件、自由文化、自由创作”。这令人振奋，但他意识到自己说得太快了，因为那是故事的结尾，所以他想回到故事的起点。

Backstory

背景故事

Some time ago, 3D printing was invented, which is something that he watched from afar; a breadboard fire when he was an undergraduate convinced him that he should be a software-only person. He is a fan of the 3D-printing culture, and enjoys the talks that come from it, but he does not participate. As part of the license-violation investigation, he and Gingerich did a crash course in the history of 3D-printing, though Gingerich already had much of the background. Kühn related some of what he learned, including that the hobbyist 3D-printing field started out as a curiosity. People who wanted a 3D printer had to build one themselves, since there were no already assembled devices on the market. Some of those who built the early printers went on to found companies that now sell 3D printers, which is a key element in the development of the community. Like Linux, 3D printers started as a hobby and remained “a hobby for a long-enough period of time that the hobby culture could not be immediately eradicated by venture capitalists”. The “wonderful thing” about 3D printing is that the people developing the software needed to run the devices looked to the free-software community and “thought twice” before they started picking licenses for their code.

不久前，3D 打印技术被发明出来，他一直从远处关注着这一领域；本科时的一次面包板起火事故让他确信自己应该只从事软件工作。他是 3D 打印文化的粉丝，也喜欢相关的讲座，但他本人并不参与其中。作为许可证违规调查的一部分，他和 Gingerich 对 3D 打印的历史进行了一次速成学习，尽管 Gingerich 本身已经具备了大部分背景知识。Kühn 分享了他所学到的一些内容，包括 3D 打印爱好者领域最初只是出于好奇。想要 3D 打印机的人必须自己动手组装，因为当时市场上没有现成的设备。一些早期打印机的制造者后来创办了如今销售 3D 打印机的公司，这是该社区发展的关键要素。像 Linux 一样，3D 打印机始于爱好，并保持了“足够长的时间作为一种爱好，以至于这种爱好文化无法被风险投资家立即根除”。3D 打印的“美妙之处”在于，开发设备运行软件的人们在为代码选择许可证之前，向自由软件社区寻求了建议并“三思而后行”。

An important piece of the tooling needed to use these devices is a program known as a “slicer”, which turns a 3D model—some slicers also help build these models—into thin 2D slices that can be converted into the language that the printer hardware understands. He likens that language to assembly language, which is an oversimplification, but helps provide a conceptual framework for him. A longtime free-software enthusiast, Alessandro Ranellucci, created a slicer, which he called “Slic3r”. Kühn said that his only criticism of Ranellucci was his choice of the name, which makes it hard to distinguish between the program and the overall type of program in a talk, so Kühn used “slicer with three” to distinguish them. The two spoke over a video chat and Ranellucci said that he chose the AGPLv3 for Slic3r to try to avoid the mess with Bambu Lab: “I anticipated all this, because my biggest worry was that someone was going to do ‘Slic3r as a service’”. While there are 3D printers that use other slicers, it is difficult to find one that is not best used with some fork of Slic3r, Kühn said. There are around 18 active forks, but the most well-known is PrusaSlicer. It came about because a friend of Ranellucci’s, Josef Prusa, saw 3D printing as not only just a business opportunity, but “a free-software business opportunity”. Prusa built a company based on providing customers with printer plans, free software, free firmware, and so on, Kühn said; that company was the dominant player in the market for a time. At the same time, a parallel market in 3D printers for manufacturing was developing. These were printers that took up a whole room and cost hundreds of thousands of dollars. Meanwhile, though, the hobbyist printers that cost $500-3000 were “becoming really, really, really good”, especially toward the top end of that range.

使用这些设备所需的一个重要工具是被称为“切片软件”（slicer）的程序，它将 3D 模型（有些切片软件也辅助构建这些模型）转换为薄的 2D 切片，进而转化为打印机硬件能理解的语言。他将这种语言比作汇编语言，虽然这是一种过度简化，但有助于他建立概念框架。资深自由软件爱好者 Alessandro Ranellucci 创建了一个切片软件，并将其命名为“Slic3r”。Kühn 说，他对 Ranellucci 唯一的批评是名字的选择，这使得在演讲中很难区分该程序和该类程序的统称，因此 Kühn 使用“带数字 3 的 slicer”来加以区分。两人通过视频聊天交谈时，Ranellucci 表示他为 Slic3r 选择 AGPLv3 协议正是为了试图避免像 Bambu Lab 这样的混乱：“我预料到了这一切，因为我最担心的是有人会搞‘Slic3r 即服务’”。Kühn 说，虽然有些 3D 打印机使用其他切片软件，但很难找到一款不是配合 Slic3r 的某个分支使用效果最好的打印机。目前大约有 18 个活跃的分支，其中最著名的是 PrusaSlicer。它的出现是因为 Ranellucci 的朋友 Josef Prusa 不仅将 3D 打印视为商业机会，而且视为“自由软件的商业机会”。Kühn 说，Prusa 建立了一家公司，旨在为客户提供打印机图纸、自由软件、自由固件等；该公司曾一度是市场上的主导者。与此同时，一个平行的制造业 3D 打印机市场也在发展。这些打印机占据整个房间，造价高达数十万美元。然而与此同时，价格在 500 到 3000 美元之间的爱好者打印机“变得真的、真的、真的非常好”，尤其是在该价格区间的上限。

Enter Bambu

拓竹（Bambu）登场

That was the state of the market in 2019 and pre-COVID 2020. During COVID, lots of people picked up hobbies, including 3D printing; that attracted a Chinese company, Bambu Lab, to the market. Kühn said that the company is rumored to have ties to the Chinese government, though that has not been confirmed. It decided to start from scratch and make 3D printers; by 2025, the company controlled 38-48% (depending on the analyst report) of the market for $500-3000 printers. In part, that is because the market for room-sized industrial printers is dying and that customers have realized that they can be replaced with fleets of much cheaper, better, and more reliable printers from companies like Bambu Lab; the company has been targeting that market, along with the hobbyist market, thus its success. Bambu Lab needed a slicer, of course, so it started shipping a modified PrusaSlicer.

这就是 2019 年和 2020 年疫情前市场的状况。疫情期间，许多人培养了各种爱好，包括 3D 打印；这吸引了一家中国公司——Bambu Lab（拓竹科技）进入市场。Kühn 表示，有传言称该公司与中国政府有联系，尽管这一点尚未得到证实。它决定从零开始制造 3D 打印机；到 2025 年，该公司已占据了 500 至 3000 美元打印机市场 38% 到 48% 的份额（取决于分析报告）。部分原因是房间大小的工业打印机市场正在萎缩，客户意识到可以用像 Bambu Lab 这样公司生产的更便宜、更好、更可靠的打印机群来替代它们；该公司一直瞄准这一市场以及爱好者市场，因此取得了成功。当然，Bambu Lab 需要一个切片软件，于是它开始随机器提供一个修改过的 PrusaSlicer。