[REFERENCE] BehaviorTree Nodes and Leaves

Delnar_Ersike · Oct 28, 2016

After having spent a few hours just setting up a single, simple BehaviorTree, I thought I'd post a reference people can look at while making Behavior Trees.

This is a list of all possible Leaf nodes in a Behavior Tree with their possible arguments outlined by number, ordered by how they appear in BehaviorTrees.xml. Each argument has a bunch of properties, this are listed below each argument. If a leaf has no arguments, no arguments are listed.

Leaf nodes for a tree are set up in the BehaviorTreeNodes SQL table and are defined by their name, while the arguments for each node are set up in TreeData and are defined by DefnId as the argument number and NodeId for the node whose arguments a given entry refers to.

Setting an argument depends on the UserData property of the argument. If it's "true", then you can use the DefaultValue field, otherwise you'll need to forward it a value or a list through the Tag field pointing to a contract that was set up with Decode Trigger + Contract Manager Decorator. Disclaimer: I'm not necessarily certain of the latter, this may change as I hear back from people and do my own tinkering.

In case I have any comments, they are added in square brackets.
__________
NodeType: Concurrent
Description: Logical And node. Runs all children until it reaches a FAILURE (can allow multiple failures if desired.)

Spoiler Arguments :

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NodeType: Priority
Description: Logical Or node. Runs all children until it reaches a SUCCESS or RUNNING

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NodeType: Sequence
Description: Special logical And node. Stops on FAILURE, but also stops on RUNNING. Resumes next turn on RUNNING node.

Spoiler Arguments :

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NodeType: Add Goal Tech
Description: Given a list of units, buildings, or techs, asks Research AI to work on them

Spoiler Arguments :

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NodeType: Build Unit
Description: Given a list of units and/or buildings and a city, builds 'best' unit [or building] at the city when queue is available.

Spoiler Arguments :

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NodeType: Find Available Unit
Description: Given a list of units, finds first unit of matching type that can get to location

Spoiler Arguments :

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NodeType: Notify Owner
Description: Sends notice back to the owning player or any other listener, with an optional integral payload.

Spoiler Arguments :

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NodeType: Barbarian Spawn Change
Description: Change the spawn rate of a barbarian tribe to prepare for raid/invasion.

Spoiler Arguments :

__________
NodeType: Run Behavior Tree
Description: DEPRECATED - DO NOT USE. Runs a behavior tree defined elsewhere. You can change data for that sub-tree, but not its structure.

Spoiler Arguments :

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NodeType: Operation Move
Description: Moves operation to the rally point.

Spoiler Arguments :

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NodeType: Decode Trigger
Description: For temporary trees only. Take the trigger you want to meet and extract information for use elsewhere.

Spoiler Arguments :

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NodeType: Choose City
Description: Given a list of buildings, pick the best city to make a building. Output city and needed improvement.

Spoiler Arguments :

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NodeType: Build Improvement
Description: Given a worker, location, and improvement, build the improvement.

Spoiler Arguments :

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NodeType: Move Unit
Description: Given a unit ID and a location, give the unit a move order. Report RUNNING until it reaches destination.

Spoiler Arguments :

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NodeType: Operation Attack
Description: As part of an operation, attack the target. [Used by AI operations that have a target that can be attacked, e.g. target enemy unit or enemy district]

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NodeType: Not
Description: Decorator that turns SUCCESS and RUNNING to FAILURE and vice versa. Does not reverse ERROR.

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NodeType: Purchase Plot
Description: Purchase plot for a city.

Spoiler Arguments :

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NodeType: Recruit Units
Description: Recruit [Select] units for a defined operation. OPERATION USE ONLY.

Spoiler Arguments :

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NodeType: Operation Attack Units
Description: As part of an operation, attack enemy units during a move

Spoiler Arguments :

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NodeType: Choose Improvement
Description: Given a list of improvement types, chooses a specific improvement to build, preferably around a city

Spoiler Arguments :

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NodeType: Barbarian Raid Check
Description: Check the score of a barbarian raid

Spoiler Arguments :

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NodeType: In Difficulty Range
Description: Decorator that runs if owner's difficulty is within range. Optionally target difficulty, optionally fail if outside.

Spoiler Arguments :

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NodeType: Settle
Description: Tells a unit to perform the settle action. FAILS if no unit is able to do so.

Spoiler Arguments :

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NodeType: Check Plot
Description: Checks if you can build the requested building or district on that location. Outputs an offending resource or feature if it fails

Spoiler Arguments :

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NodeType: Clear Plot
Description: Orders a unit to clear the current tile. FAILS if no unit is able to do so.

Spoiler Arguments :

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NodeType: Barbarian Recruit
Description: Recruit members from a tribe for a raid or invasion.

Spoiler Arguments :

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NodeType: Interval
Description: Lets a child run for N turns before rechecking it

Spoiler Arguments :

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NodeType: Operation Defend Units
Description: As part of an operation, protect your units that might otherwise be destroyed.

Spoiler Arguments :

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NodeType: Turn Limiter
Description: Only lets a child node run for a limited number of turns before failing.

Spoiler Arguments :

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NodeType: Operation Change Target
Description: As part of an operation, if you can't take the current target, find a new one or give up.

Spoiler Arguments :

__________
NodeType: Contract Manager Decorator
Description: Manages a contract, can limit turns until it is run.

Spoiler Arguments :

__________
NodeType: Operation Attack City
Description: As part of an operation, attack a city

Spoiler Arguments :

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NodeType: Make Formation
Description: Create (or destroy) a formation of units [corps, armies]

Spoiler Arguments :

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NodeType: Protect Unit
Description: Keep a non-operation unit safe if its health is below specified fraction

Spoiler Arguments :

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NodeType: City Attack
Description: Cities attack enemy units within range, with preferences as described (none required)

Spoiler Arguments :

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NodeType: Reserve Plot
Description: Reserve a city plot so that other trees will leave it alone

Spoiler Arguments :

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NodeType: Operation Pillage
Description: Pillage nearby improvements and districts

Spoiler Arguments :

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NodeType: Operation Siege City
Description: Pillage nearby improvements and districts [while surrounding a city]

Spoiler Arguments :

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NodeType: Garrison City
Description: As part of an operation, garrison a unit in a friendly city

Spoiler Arguments :

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NodeType: Is City Threatened
Description: Tell if city that is operation target is still threatened

Spoiler Arguments :

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NodeType: Is At War
Description: Tell if player is at war

Spoiler Arguments :

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NodeType: Find Unit Targets
Description: Find places for all owned units to go

Spoiler Arguments :

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NodeType: Upgrade Units
Description: Upgrade any upgradeable units

Spoiler Arguments :

Continued in next post...

Delnar_Ersike · Oct 28, 2016

__________
NodeType: Has Great Person
Description: Succeeds if the tree has a great person of the appropriate type [selected]

Spoiler Arguments :

__________
NodeType: Use Great Person
Description: Uses the great person ability, including founding a religion

Spoiler Arguments :

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NodeType: Cancel Contract
Description: Cancel a tagged contract [set up through the Decorator]

Spoiler Arguments :

__________
NodeType: Lock Units
Description: Allow/disallow units to be recruited off the team [i.e. away from a given AI operation]

Spoiler Arguments :

__________
NodeType: Operation Diplomacy
Description: Diplomacy actions and tests

Spoiler Arguments :

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NodeType: SPY: Choose Mission
Description: Choose a spy mission for the spy's current city

Spoiler Arguments :

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NodeType: SPY: Do Operation
Description: Execute the spy's current mission

Spoiler Arguments :

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NodeType: SPY: Travel
Description: Move the spy to the chosen city (or home)

Spoiler Arguments :

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NodeType: ARCHAEOLOGY: Dig
Description: Have an archaeologist dig at the specified location

Spoiler Arguments :

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NodeType: ARCHAEOLOGY: Donate
Description: An archaeologist moves to his home and donates any carried artifact to his museum

__________
NodeType: Operation Naval Escort
Description: Recruit naval escorts to an operation and ferry units across the waters

Spoiler Arguments :

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NodeType: Has Player Ability
Description: Decorator that checks for player ability before handing control to child

Spoiler Arguments :

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NodeType: Build Production
Description: Use a builder charge to accelerate a wonder or district (if allowed)

Spoiler Arguments :

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NodeType: Has Inquisition
Description: Returns true if the specified player has launched an inquisition

Spoiler Arguments :

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NodeType: Launch Inquisition
Description: Launches an inquisition using an attached unit, if possible

Spoiler Arguments :

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NodeType: Will use nukes
Description: Checks if the AI is willing to use nukes against his opponent (Gandhi always will)

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NodeType: Operation Launch nuke
Description: Launch nuke at target

__________

Delnar_Ersike · Oct 28, 2016

Shifted · Oct 29, 2016

Thanks for the references. I've had some experience with coding behavior trees and other AI techniques for games before, and was wondering how one would go about modding the game's AI. If I'm not mistaken, your post seems to imply you can make your own behavior trees combining these predefined behaviors by specifying the tree on the database? I was also wondering if you would know if there's a way to mod the game's AI at the code level, with the full liberty given by (what I assume the game uses) C++? Would I need to wait for the SDK for that?

Delnar_Ersike · Oct 29, 2016

Shifted said:
Thanks for the references. I've had some experience with coding behavior trees and other AI techniques for games before, and was wondering how one would go about modding the game's AI. If I'm not mistaken, your post seems to imply you can make your own behavior trees combining these predefined behaviors by specifying the tree on the database? I was also wondering if you would know if there's a way to mod the game's AI at the code level, with the full liberty given by (what I assume the game uses) C++? Would I need to wait for the SDK for that?

You need to wait for Firaxis to decide to release CvGameCoreDLL's source code. Firaxis released Civ5's SDK a week after release and Civ5's CvGameCoreDLL a year and a half after release. It has been more than a week since Civ6's release, and there's no SDK in sight, so I wouldn't be holding out too much hope for Civ6 AI modding.

Shifted · Oct 29, 2016

Ahh, that's pretty sad. Thanks though!

notque · Apr 10, 2017

While reading through this topic, I found this link helpful so wanted to share.

http://www.gamasutra.com/blogs/ChrisSimpson/20140717/221339/Behavior_trees_for_AI_How_they_work.php

Tiramisu · Nov 17, 2017

Thanks for the guides, but I still do not understand how the nodes are connected with each other. Per BehaviorTreeNodes-Row there is at most only one "JumpTo" entry, which could define a connection from one node to another. However, I would have expected that a node could have more than one child. I simply cannot see how the trees are defined.

Edit: Maybe "JumpTo" has a different meaning. It could define some kind of bracket in the syntax, meaning that the bracket ends at the node of "JumpTo" (taking the numeration order of the nodes into account), while the node in the row of "JumpTo" is a parent node. So all the nodes within the bracket of the parent node are its children nodes.
This makes sense to me right now, but I have to take a close look to verify it.

Edit2: Some node datas in Delnar's posts might be missing. E.g. I cannot find "Operation Air Assault". Just saying.

Infixo · Jan 1, 2019

Tiramisu said:
Thanks for the guides, but I still do not understand how the nodes are connected with each other. Per BehaviorTreeNodes-Row there is at most only one "JumpTo" entry, which could define a connection from one node to another. However, I would have expected that a node could have more than one child. I simply cannot see how the trees are defined.
Edit: Maybe "JumpTo" has a different meaning. It could define some kind of bracket in the syntax, meaning that the bracket ends at the node of "JumpTo" (taking the numeration order of the nodes into account), while the node in the row of "JumpTo" is a parent node. So all the nodes within the bracket of the parent node are its children nodes.
This makes sense to me right now, but I have to take a close look to verify it.

Yeah... I am having the same problem, e.g. can't picture the tree from the flat db table. Could use some enlightenment here.
Nodes themselves, parameters, etc. entire reference posted here - this is available directly in the database, so this part is actually easy.
I like the idea of "JumpTo" as a kind of bracket, must investigate.

[REFERENCE] BehaviorTree Nodes and Leaves

Delnar_Ersike

Prince

Delnar_Ersike

Prince

Delnar_Ersike

Prince

Shifted

Chieftain

Delnar_Ersike

Prince

Shifted

Chieftain

notque

Artificially Intelligent

Tiramisu

Warlord

Infixo

Deity

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