BH3 provides the necessary tools to create the behavior of non player characters for your games, like RPG, First Person Shooters, strategy, BH3 can help you bring life to your games.BH3 is a behavior tree tool for Unity built on Unity Visual Scripting. Designers build AI without writing code; programmers write reusable nodes in C# and wire them the same way.Three ideas do most of the work:Ports separate what a node does from where its data comes from.A node reads a port. The value can come from a Blackboard variable, a literal, another node, or a whole Visual Scripting graph, and the node never needs to know which. No more custom code just to keep a Blackboard up to date.A branch is a function.Put a branch in its own tree asset, pass it parameters through ports, and run it from any agent. Behaviors are shared across characters instead of copied, which keeps large projects manageable.Guards decide when a branch may run, and when it must stop.A Reactive Guard watches a condition while its branch runs, aborts the branch when the condition drops, and can take over from a lower-priority branch when it rises.When an agent does the wrong thing, BH3 has already recorded what happened. Scrub back to the moment, read why the node did what it did, and set a breakpoint for the next time.FEATURESEditor* Custom node-based graph editor* Sub-trees with parameters* Explicit execution order, shown as a priority badge on each child* Problem badges on nodes that cannot work, with one-click repairs* Recovery for trees whose node class was renamed or deletedVisual Scripting* Feed any port from a Visual Scripting graph* Functions: shared graphs with declared inputs, reusable across trees* Create custom node logic without C#Debugging* Flight recorder: every node, guard and variable is recorded during play* Timeline: scrub to any tick, save and load recordings* Why panel: explains why a node ran, failed, or was taken over* Variable Watch: what a variable held at that tick, and which node wrote it* Breakpoints on nodes, variable writes and guard changesREQUIREMENTS* Unity 6000.4 or newer* Unity Visual ScriptingGithubDocumentationVideo tutorialsDiscordQuestions: hi.arcane.onyx@gmail.comCustom Node EditorRuntime DebuggerUnity Visual Scripting IntegrationConditional Execution NodesNode PortsVariablesBuilt in FPS Example to show case the best practices.I started BH3 in 2023 and built it by hand for its first three years. It began as a tool for another project, which is still unreleased.Since 2026 I have used Claude Code as part of my development workflow. It helps me draft and shape features, and sometimes brings them to completion. It also writes tests, fixes bugs and drafts documentation.
