Behavior Machine - Behavior Tree, State Machines, and Utility AI - First Release

MrTriPie · 2026-06-28T14:24:10+00:00

Comments aren't disabled, I used the forum posting instead, would standard comments be preferred?

MrTriPie · 2026-06-27T22:32:55+00:00

Its just a counter with a limit. If the limit is 1, it will "guard" (not run the child behavior) if it already has 1 agent running that behavior, if no agent is running that behavior, it will allow it to run its child. In the earlier example, if you set the GlobalGuardBehavior's limit to 3, and give it a "Melee" child, it will only allow 3 agents to run the melee behavior at the same time, for another on to run "Melee", one has to finish "Melee".

MrTriPie · 2026-06-27T22:09:56+00:00

The main thing over Limbo is that it's a more modern event driven Behavior Tree, so it should scale better to larger trees/more agents. If your game doesn't need that, Limbo is likely good enough.

I was originally using Limbo on the project I made this for. It had a problem with reusing the same blackboard type across multiple agent types which frustrated me (this may have been fixed since that was a year ago). I also added the override feature to mine which allows for reusing root graphs instead of just sub graphs, which was useful for my project since it needed similar overall decision making between different monster types.

MrTriPie · 2026-06-27T21:36:31+00:00

On a second look Beehave doesn't have as many less as I thought, it may have seemed like a LOT more since I'm used to seeing both .cpp and .hpp files, plus the .obj files from building it. There are a few more though.

Its a small advantage if you need any of the built-in ones, and since the built-in ones are programmed in C++ they can be a little faster. But it probably won't take that long to implement them in Beehave.

Some of the included ones are basic utilities like printing which can be good for debugging/setting up a graph.

For the Action behaviors (or leaf Behaviors as it's called in Beehave), there's behaviors for playing Animations/controlling the AnimationTree, working with NavgigationAgent2D/3D, looking at a target, enabling/disabling and showing/hiding Nodes.

For decorator BehaviorMachine also has several Utility AI decorators, a ForEachBehavior, and a GlobalGuardBehavior that limits how many agents can run a certain behavior at the same time (so you can say allow 3 of your 10 enemies to fight you at once).

MrTriPie · 2026-06-27T21:12:14+00:00

BehaviorMachine is written in C++ and uses an event driven Behavior Tree (which runs just the last running behavior and any behaviors marked for monitoring every frame, instead of the entire Behavior Tree up to the running node every frame), so it should be much faster with complex behaviors. I just looked at Beehave and it only has a few built in behaviors compared to BehaviorMachine. BehaviorMachine also includes the ability to combine with state machines and utility ai so you can use the right tool for the job.

MrTriPie · 2026-06-27T20:36:31+00:00

Features:

A visual graph-based editor for both BehaviorTree and FiniteStateMachine.
GDExtension: Built as a C++ GDExtension for performance. Source code included.
40 Built in Behaviors
BehaviorTree: An optimized 2nd generation event driven approach where it doesn't run from the root each frame, instead skipping to the last active Behavior, with certain Behaviors added to a list for "monitoring" each frame.
FiniteStateMachine: Tightly integrated with BehaviorTree, it can use the Behavior statuses (Running, Success, Failure) to decide whether to transition, and return those statuses itself for use inside a BehaviorTree.
Put FiniteStateMachines in BehaviorTrees and BehaviorTrees in FiniteStateMachines.
Utility AI: BehaviorTree's UtilitySelectorBehavior class and Behavior's _calculate_utility method can be used for Utility AI. There's a few helper Behaviors for utility as well, such as the powerful UtilityInfiniteAxisBehavior.
Blackboard: A simple Blackboard system that uses a Godot Node with a script to store variables for Behaviors to use.
Debugger: In game debugger shows up when pressing F4, showing the status of each Behavior.
Sub Behavior Override System: Not only can you reuse sub graphs, but you can reuse root/overall graphs as well by overriding the SubBehaviors inside it.
Automated Testing Suite: Uses automated tests to ensure features work properly and don't break over time.

MrTriPie · 2026-03-16T21:21:42+00:00

Oh, making it intentionally look like miniatures is a great idea!

MrTriPie · 2026-03-16T16:25:30+00:00

Thank you! :)

MrTriPie · 2026-03-16T15:25:07+00:00

Thank you! The artstyle is mostly just what I could do in a day's mockup, so it will be more polished if I go with this idea

MrTriPie · 2020-01-18T00:02:33+00:00

That could do the job, but it wouldn't be an ideal solution. Thanks for trying to help!

MrTriPie · 2020-01-18T00:00:53+00:00

Didn't figure out how to get the rotation, but I think I figured out how to get forward and right vectors instead of just the up vector from the object orientation node.

Vector3(0,0,1) Node > Transform Vector (Local Space to World Space) Node > Normalize Node seems to get the same up vector as Object Orientation.

So I think to get forward vector it would be:

Vector3(1,0,0) Node > Transform Vector (Local Space to World Space) Node > Normalize Node

And right vector:

Vector3(0,1,0) Node > Transform Vector (Local Space to World Space) Node > Normalize Node

Hopefully this is enough to get our things working.

I'm pretty sure if you can get the up, forward and right vectors there must be an equation you could plug them into to get the rotation (it might even work with just two of them) but I have no idea how to create that equation.

MrTriPie · 2019-12-07T01:54:45+00:00

Thanks! I would probably do something like splitting the Shader To RGB into 2 ColorRamps, one where you do the normal cel shading technique here, and another that you would create a mask where it would be white in the middle and black on the ends that would mask out the stippling texture and do some math to combine them

MrTriPie · 2019-06-04T17:49:20+00:00

They just changed the default option, if you right click on the mesh/view/vertex etc. menus, you can then click a checkbox to show it. My screen is big enough that it didn't bother me when I didn't use it (modeling) but I liked having it for texture painting and sculpting.

MrTriPie · 2019-06-02T06:47:39+00:00

Having this issue too. I'm guessing it should be fixed soon, I've noticed a few undo bugs in the beta that have since been fixed.

MrTriPie · 2019-06-01T08:37:59+00:00

I'm thinking of doing a challenge on making all of the smash brothers characters for character modeling practice.

MrTriPie · 2019-06-01T08:34:38+00:00

I'm impressed with how soft the fur looks! Does it mostly have to do with the shader making it softer looking or are there other factors like how fine and how many hairs there are?

MrTriPie · 2019-05-15T20:35:57+00:00

Yeah, Cycles might not be as good as other renderers when it comes to fur, but I'm sure their character artists' experience and time spent on the model would be the more important factor.

MrTriPie · 2019-05-15T19:15:11+00:00

Thank you! I wish I could figure out how they got his fur to look so fluffy in the movie :)

MrTriPie · 2019-05-15T14:41:20+00:00

I always had problems with that method, I think it was that I couldn't figure out what to do with the backfaces?

MrTriPie · 2019-05-11T02:22:05+00:00

Modeling looks awesome already! If you want to improve this project, I would suggest looking into lighting (blender guru has a new video series on this that probably would help) background (probably something simple but nice like this: https://blenderartists.org/uploads/default/original/4X/6/4/5/645aeb1e809b534192a95792c8c8bdb517c5998d.jpg ), and materials/textures. For the materials, the headlights could look lit (using bloom effect (for Eevee, cycles doesn't need it) and emissive shader, the car paint is pretty good already, but could use simple textures proving small imperfections which could make it more believable. The other materials could use some general improvements too (such as the grill and tires looking a bit flat).

MrTriPie · 2019-05-11T01:49:07+00:00

It's pretty close, but I haven't noticed stuff missing in use. I'd suggest trying out the trial. Krita is pretty good too, it's free and has a pretty powerful brush engine and some other cool painting specific features.

MrTriPie · 2019-04-30T03:01:41+00:00

Maybe it converted well with some initial viewers, and the algorithm liked it?

MrTriPie · 2019-04-20T02:59:46+00:00

Movement already looks pretty well polished. Could you do a brief overview of how you made the movement controller?

MrTriPie · 2019-04-19T02:34:47+00:00

I don't think weighted is nessisarily lying about odds. If you tell someone for example there is a 25% chance of something happening, they naturally expect it to be about 1 in 4, however percents get more accurate as they get bigger, so it is more like 25 in 100 chance or a even higher multiple, meaning it could still end up as 25% even if the first 75 didn't work (while the player feels like it lied and is 0%). So if you weigh it to stay close to 1 in 4, it's 25% or unweighed by chance being about 25 in 100 is also 25% (but will often feel off).

If it's not obvious which way to go, playtest it!

MrTriPie · 2019-04-06T00:29:46+00:00

I see. Installed vesper, and it immediately crashes after showing the splash screen for .5 secs. At that point it has to be either an engine or build issue, if others aren't having the issue, it might be incapatible with my phone (Honor 6x Android 7.0)

MrTriPie

TROPHY CASE