Why Josef Prusa is calling out Bambu Lab over open source code
Josef Prusa claims Bambu Lab violates AGPL software licenses and warns about hidden security risks in their closed-source network plugins.
You probably think your 3D printer is just a tool for making plastic trinkets. It's a simple machine that turns digital files into physical objects. But what if that machine is watching you back?
Josef Prusa, the founder of Prusa Research, recently raised some red flags. He claims Bambu Lab is ignoring the rules of open source software. It's not just about code. It's about who really controls your hardware.
The 3D printing world is currently split on this issue. Some want convenience. Others want total control over their data. Let's look at why this fight matters for everyone with a printer on their desk.
The long history of shared code
Most 3D printing software shares a common ancestor. PrusaSlicer relies on Slic3r, a project started by Alessandro Ranellucci years ago. It's a classic example of how open source projects grow. People add features, fix bugs, and share the work with the world.
This cycle works well. You take code, you improve it, and you give it back. That's the core of the AGPL-3.0 license. It ensures that the software stays free for everyone. It stops companies from taking public work and locking it behind a wall.
Many firms like Creality, Elegoo, and Bambu Lab built their tools on this foundation. They used existing code to get their printers running fast. It saved them years of development time. But the catch is that they must share their changes too.
The black box in the machine
Prusa says Bambu Lab broke this deal from the very beginning. They took PrusaSlicer but kept their networking plugin hidden. It's a binary blob that you can't look at or check for bugs. He calls it a black box.
The company claims the slicer and the plugin are separate. They say the slicer works fine without the cloud features. But Prusa disagrees. He thinks the two parts are glued together just to skirt the rules of the license.
This creates a weird situation. You can use the printer in LAN mode, but the cloud features are the main selling point. Most users just click print in the app. They never see the code running behind the scenes. They don't know what it sends or where it goes.
Prusa found out about Bambu Lab before they even launched. His servers caught telemetry data from their early builds. They had accidentally pointed their software to his database. That's when he realized they were building a fork of his work.
He didn't sue them back then. He thought it was too hard to fight a company without a physical product to track. Now, he regrets that choice. He sees legal threats against smaller developers and feels it's time to speak up about the risks.
The hidden risks of closed software
The real worry here is security. When software is open, anyone can read it. You can see if it's doing something weird. You can check if it's sending your private data to a server in another country.
With a closed black box, you're just trusting the company. You have no way to audit the connection. If the software updates, it could change how it works in an instant. You wouldn't even know it happened.
China has laws that require companies to help with intelligence gathering. This isn't a theory. It's written into their legal framework. If the government asks for access, these firms have to provide it. It doesn't matter if the engineers want to be helpful or not.
We've seen what happens when people speak out. The case of Naomi Wu is a sad reminder. She was a major voice in the community. Then she disappeared from the public eye after warning people about spyware. It's a chilling thought for anyone in tech.
What comes next for the community
The industry is at a turning point. We have to decide if we value ease of use over our own safety. Do we want printers that just work, or do we want ones we can trust? It's a tough choice for most hobbyists.
If more companies follow this path, we might lose the open nature of 3D printing. We could end up with a few giant firms that control everything. That would hurt innovation for everyone. It would turn a fun hobby into a gated garden.
I think the community needs to push for more transparency. We should demand open source alternatives that don't hide their code. If we don't, we're just buying plastic bricks that someone else controls.
Quick questions answered
What is the AGPL license? It's a license that forces you to share your source code if you distribute modified versions of the software.
Why is Prusa mad? He thinks Bambu Lab is using his code but hiding their own networking plugin to avoid sharing it with the community.
Is the printer safe to use? It's a risk assessment. If you don't trust the cloud, you can use LAN mode or an SD card to keep your data offline.
What is a networking blob? It's a piece of software that runs on your computer but isn't open for anyone to inspect or audit.
Can I stop my printer from sending data? Yes, by using offline modes like LAN-only or simply not connecting the device to the internet.
My honest take on this
I think the situation is pretty clear. Bambu Lab built a great product, but they did it by cutting corners on the rules. They took the hard work of others and kept their own secret sauce private. That's not how open source is supposed to work.
The thing that gets me is the lack of trust. I don't like using any software that I can't look at myself. When a company forces a black box onto my machine, I start to wonder what they are hiding. It shouldn't be this way.
I also think we need to be realistic about the geopolitical side. We can't ignore the laws in the countries where these companies are based. If the state can demand access to your data, you should assume they eventually will. It's just common sense.
Honestly, my take is that we need to support companies that build in the open. If we keep feeding firms that ignore the social contract, we'll eventually lose the freedom we have now. I'll stick to machines that let me see what's under the hood.