Hey everyone,

I've been building a free, source-available Behaviour Tree tool for Unity for my own projects, and figured I'd share it here in case it's useful to anyone.

GitHub: https://github.com/vadimburym/DODBT

The core idea is simple: the Behaviour Tree only makes decisions, and everything else (movement, animation, whatever you've got) just executes them. I also tried to keep a realistic production flow in mind, where a developer builds the tree, a designer tweaks it, QA debugs it, and then you ship an optimized build.

A bit about what it actually does:

There's no MonoBehaviour at runtime and no allocations during ticking. One compiled tree can be shared across many agents, while each agent keeps its own context and state. It ships with a visual graph editor and a runtime debug mode, and the graph gets compiled into a runtime form, so the editor data never ends up in your build. There's no forced Blackboard either, so leaves can pull dependencies through DI, a ServiceLocator, or just a direct context. It also plays nicely with ECS if you only want to use it as a decision layer.

Some honest caveats:

The editor and debug tools currently need Odin Inspector, though the runtime/build side doesn't depend on it. There are no decorators yet. It's an early version, but already usable. And it's probably more interesting to gameplay and AI programmers than to someone looking for a full drag-and-drop AI solution.

On the roadmap, I already have a separate DOTS-compatible version mostly working. Burst, BlobAsset and Jobs compatibility, plus some quality-of-life stuff, are done. Still on the list: code generation, debug mode for the DOTS version, decorators, more examples, better docs, general polish, and hopefully making the editor work without Odin.

If any Unity gameplay, AI or tools folks want to take a look, I'd really appreciate the feedback. A few things I'm genuinely unsure about:

Does this kind of architecture fit how you build your projects?
Which decorators would you want added first?
Is the Odin dependency okay if it's only for the editor and debug tooling?
What examples or docs would actually make this easier to adopt?
Is the ECS decision-layer idea clear, or should I explain it better?
Would you rather see it under a more permissive license like MIT or Apache-2.0?
Thanks for reading.

Data-oriented Behaviour Tree for Unity - clean C# runtime and full production workflow