Blender builds and releases include python script add-ons that extend its functionality. This page has information for developers who want to have their add-on bundled with Blender.
Mandatory prerequisites to get an add-on accepted
You must be aware that your add-on will be integrated into the official Blender distribution. Therefore you must ensure there is continuous support for keeping your add-on working and fixing bugs as they appear. So you must commit yourself (or find a maintainer who does it for you) to do the maintenance (see General Guidelines for Add-on Developers below)
- Add-ons Repository on projects.blender.org
- Submit an add-on by making a pull request for this repository
Key requirements for Add-ons¶
We want to implement fair and uniform rules for all add-ons included in Blender releases.
- Base line is that each add-on that gets bundled, is meant to function at the same quality level as other Blender features. What we require from C/C++ we also require from Python scripts, not only technically, but also following Free Software principles.
- Add-ons in a release are fully functional and useful additions to Blender, not requiring or advertising extensions or options available outside of blender.org.
- While there is a lot of room to extend Blender in different ways, please note that functionality or tweaks specific for your own workflow, or only minor changes to existing tools may be rejected for inclusion in Blender. We decide on a case by case basis if an add-on gets included or not. Getting your add-on tested by users helps here.
This implies that:
- Blender does not include add-ons in a release that require internet to work, unless it connects to blender.org based on explicit user permission. For such (new) add-ons we will start a new module on blender.org.
- Add-ons in Blender releases offer the full documentation on blender.org.
- Blender does not include add-ons in a release that require installing additional modules.
- Blender does not include add-ons in a release that create a bridge to non-free (non GPL compliant) software.
Add-ons are hosted in two Git repositories, that are automatically checked out with the main Blender repository when running make update.
- Blender Add-ons: included in official releases on blender.org, strictly reviewed
- Blender Add-ons Contrib: included in test builds in the Testing tab, for more adventurous users
They can be found in these two directories of the main Blender repository:
Submitting an Add-on¶
- Follow the Guidelines for add-ons when implementing it.
- Ensure your addon is publicly available and well documented.
- Submit the add-on as a pull request with the relevant links to your addon and its full documentation.
- Try to get your add-ons tested by users, gather feedback and improve as needed.
The reviewer will decide if the add-on can be included in official release, included in the Contrib repository or can't be included. If the add-on is in the Contrib repository and matures, you can later message in the #python channel on blender.chat and ask for the add-on to be moved to the repository for official releases.
If the add-on is on track to be included in official releases, you may be asked to submit it to our Code Review tool for a closer review.
General Guidelines for Add-on Developers¶
If you attempt to submit your add-on either to the contrib section or to the release section of the add-on Repository, then your add-on will undergo a review process. Within this process changes may be requested to keep inline with good coding practices. Those changes may be provided by you or by the reviewer. This will be clarified with the reviewer on a case by case basis.
Once your add-on is accepted and hosted in the Blender release section or the contrib section, you become responsible for maintaining your add-on and you get commit permissions to the add-on repository...
Duties of an Add-on maintainer¶
As soon as you got the commit permissions you...
- Maintain and further improve your add-on by yourself.
- Ensure your add-on keeps working with new Blender Releases and API changes. Therefor check regularly & keep up to date in between Blender Official release to ensure your add-on is working in the next release of Blender.
- Handle bug reports from users.
- When you add new features then you also should add brief documentation and explanations to the Blender release notes.
- Check regularly for patches to your add-on from other users and eventually commit updates they make using the current git version of the add-on as the base.
Avoid unmaintained Add-ons
Add-ons that are not supported (or no longer supported) by their authors may be removed from Blender if they are broken & we can not find a maintainer.
- Write good commit messages that explain which add-on and what exactly you change (good example).
- It's acceptable to test other developers’ add-ons, and commit small fixes to their code (like a typo or obvious bug fixes).
- Optional: make your script pep8 compliant and follow best practice.
- Commit code that is not GPL2+ or compatible with it.
- Commit code you are not the author of (unless you have the author’s authorization).
- Commit big changes to other add-ons (unless you get the author’s permission).
- Commit binary files like .exe, .pyc, .pyd, .dll, .whl, etc.
- Add commit logs in your code (Git logs should be enough)
Working with Git¶
The same advice from our Git Usage page applies here.
If you have a full Blender checkout, you can go into the
and it's as if you are working in the Blender Add-ons or Blender Add-ons
Contrib repositories directly. You can do all the typical git commands
there for adding files, committing changes, and fetching and rebasing
Optionally you can choose to clone the individual repositories and work there:
Bugs for all add-ons are reported to the add-ons repository on projects.blender.org. If a bug is filed for your add-on, the bug will be assigned to you as the add-on maintainer.
You can also help out with bugs that are marked as Needs Triage in the tracker, to assign them to the right maintainer, confirm the problem or even fix the bug yourself.