The Short Version
Everything on this site — the guides, the CAD files, the calculators, the lot — is free to use for personal, non-commercial purposes. You can download files, learn from them, build with them, and modify them. You just can’t sell them or pass them off as your own.
If you modify or build upon something you find here, you need to credit rebreathology.com and share your version under the same terms. If you create something new and want to contribute it back to the project, we’d love that — but there are a few rules to make sure the library stays free and open for everyone.
That’s genuinely it in a nutshell. The rest of this page explains how the licences work, what you can and can’t do in practice, and what happens when you contribute. If you’re not a lawyer (and even if you are), we’ve tried to keep it readable.
Two Licences, One Project
Rebreathology.com uses a dual-licence approach. Different types of content are covered by different licences, because content and code work differently in the real world and need different protections. Think of it like a car: the bodywork and the engine both keep you moving, but you wouldn’t use the same maintenance manual for both.
Content, guides, CAD files, and visual assets
All the written content, educational guides, CAD files, infographics, and visual assets are licensed under Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0). In plain English, that means you’re free to share and adapt the material as long as you credit the source, don’t use it commercially, and share any adapted versions under the same terms.
Code, web apps, and interactive tools
All the software — the calculators, interactive tools, scripts, and web applications — is licensed under the GNU General Public License v3.0 (GPLv3). This means you can use, copy, modify, and distribute the code freely. But if you distribute a modified version, you must also release your source code under the GPLv3. This ensures that improvements to the tools always flow back to the community.
Which licence covers what?
| Content Type | Folder | Licence |
|---|---|---|
| Website copy and pages | website/ | CC BY-NC-SA 4.0 |
| E-learning guides and articles | guides/ | CC BY-NC-SA 4.0 |
| CAD files and assemblies | cad/ | CC BY-NC-SA 4.0 |
| Infographics and visual assets | infographics/ | CC BY-NC-SA 4.0 |
| Project documentation | docs/ | CC BY-NC-SA 4.0 |
| Web apps, tools, and calculators | apps/ | GPLv3 |
If you’re ever unsure which licence applies to a specific file, check the licence notice within the file itself. When in doubt, assume CC BY-NC-SA 4.0 for content and GPLv3 for anything that’s primarily code.
Using Our Content and CAD Files
We want people to use this stuff — that’s why it’s here. But to keep the library free and useful for everyone, there are a few ground rules.
- Download files for your own personal use
- Use CAD files to build your own rebreather
- Modify and adapt files to suit your needs
- Share files directly with friends and dive buddies
- Use content for non-commercial education and research
- Quote or reference our guides with attribution
- Sell files, guides, or CAD models — in any form
- Upload files to other CAD libraries or file-sharing sites
- Use content in a commercial product or service
- Remove attribution or claim the work as your own
- Distribute modified versions under different licence terms
Sharing with others
If a friend or fellow diver wants access to something on this site, we’d prefer you point them to rebreathology.com directly rather than sending files around. That way they always get the latest version, and they get the context, safety notes, and supporting documentation that goes with it. But we’re realistic — we know people share files, and the licence allows it as long as attribution is maintained and no money changes hands.
Modifying files
If you modify a CAD file or adapt a guide, that’s great — that’s exactly what open source is for. But you must acknowledge the original creator and the fact that the original came from rebreathology.com. If you share your modified version with others, it must be under the same CC BY-NC-SA 4.0 licence terms. You can’t take something free, change it, and then lock it behind a paywall.
The NonCommercial clause in our licence means exactly what it says: you cannot use these materials for commercial purposes. This includes selling printed parts made from our CAD files, offering paid courses that reproduce our content, or bundling our files into a product or service you charge for.
Contributing to Rebreathology
Rebreathology.com is an open-source project, and we welcome contributions from the community. Whether it’s a new CAD model for the parts library, an article on a technique you’ve perfected, a bug fix for one of the calculators, or even a correction to a typo — it all helps.
However, to keep the library free, open, and legally clean for everyone who uses it, we need contributors to agree to a few things before we can accept submissions.
You must own what you submit. By contributing content to rebreathology.com — whether that’s a CAD file, an article, a guide, an image, or code — you confirm that you are the original creator or that you have the legal right to submit it. Do not submit work that belongs to someone else, is copied from a commercial product, or is derived from content with incompatible licence terms.
Contributions are provided freely. All contributions are made voluntarily and without charge. By submitting content, you agree that it will be made available to all users of rebreathology.com free of charge, under the same licence terms that govern the rest of the project (CC BY-NC-SA 4.0 for content and CAD files, GPLv3 for code).
Ownership transfers to the project. By submitting content, you grant rebreathology.com a perpetual, irrevocable, worldwide, royalty-free licence to use, modify, distribute, and display your contribution as part of the project. In practical terms, your contribution becomes part of rebreathology.com. You will be credited as the original creator, but you may not later withdraw the contribution or restrict how the project uses it.
Credit where it’s due. We believe in proper attribution. Contributors will be credited by name (or pseudonym, if preferred) alongside their contributions. If your CAD file ends up in the library, your name stays with it.
Quality and safety review. All contributions are subject to review before being published. We reserve the right to edit, modify, or decline any submission — particularly where safety, accuracy, or consistency with the rest of the site is concerned. This isn’t about gatekeeping; it’s about making sure everything on the site meets the standard our users expect and deserve.
No liability. Contributors are not liable for how others use their contributions, and rebreathology.com is not liable for any loss or damage arising from the use of contributed content. The same disclaimer that applies to the rest of the site applies equally to community contributions.
Open source works because people give freely. Every CAD file, every guide, every bug fix makes the whole project better for everyone. If you’ve got something to contribute, don’t be shy — the community is better for it.
The Full Legal Text
Everything above is our best effort at explaining the licences in plain English. But the actual legal terms are defined by the licence documents themselves. If you need the full, unabridged legalese — or if your organisation requires it — here they are:
In the event of any conflict between our plain-English explanations on this page and the actual licence texts linked above, the licence texts take precedence.
Questions?
If you’re unsure whether a specific use is permitted, or if you’d like to discuss contributing to the project, please get in touch. You can open an issue on our GitHub repository or contact us directly. We’d rather answer a question now than sort out a misunderstanding later.
This project exists because people share knowledge freely. Thank you for respecting the terms that make that possible.