StateTree Setup¶

Step-by-step guide for building the master StateTree from scratch. If you're using the included ST_AxM_Master, this shows you how it's wired and how to customize it.

Schema¶

Set the StateTree's Schema to StateTreeAIComponentSchema. This provides AIController and Pawn as context objects for binding.

Global Tasks¶

Add all four to the root state's Global Tasks list:

1. AxM Perception (Global)¶

Field	Bind To
Controller (Context)	`AIController`
TargetActor (Output)	— available for binding
LastKnownLocation (Output)	— available for binding
HomeLocation (Output)	— available for binding
DistanceFromHome (Output)	— available for binding
StimulusLocation (Output)	— available for binding
HearingStrength (Output)	— available for binding

2. AxM Suspicion (Global)¶

Field	Bind To
HearingStrength (Input)	`Perception.HearingStrength`
SuspicionDecayRate (Parameter)	0.15 (or bind from Config)
InvestigateThreshold (Parameter)	0.4 (or bind from Config)
SuspicionGainMultiplier (Parameter)	1.0 (or bind from Config)
SuspicionLevel (Output)	— available for binding
bIsSuspicious (Output)	— available for binding

3. AxM Config (Global)¶

Field	Bind To
Controller (Context)	`AIController`
LeashRadius (Output)	— available for binding
PatrolWaitDuration (Output)	— available for binding
All movement speeds (Output)	— available for binding
All suspicion params (Output)	— available for binding
All alert state tags (Output)	— available for binding

4. AxM Target Tracking (Global)¶

Field	Bind To
Controller (Context)	`AIController`
TargetActor (Input)	`Perception.TargetActor`
DistanceToTarget (Output)	— available for binding
HasLineOfSight (Output)	— available for binding

State Hierarchy¶

Root: Alive
├── [Patrol]            ← default entry state
├── [Investigate]       ← parent state
│   ├── [GoToStimulus]  ← default child
│   └── [ScanArea]
├── [Search]            ← parent state
│   ├── [GoToLastKnown] ← default child
│   └── [SearchArea]
└── [Combat]            ← linked sub-StateTree

Patrol State¶

Tasks:

Task	Field	Bind To
AxM Patrol	Controller	`AIController`
	WaitDuration	`Config.PatrolWaitDuration`
	AcceptanceRadius	50.0
	bLoop	true

Note

If the AI Controller has no PatrolRoute assigned, the Patrol task succeeds immediately and falls through to transitions. Add a StateTree Delay task after AxM Patrol as a fallback idle.

Transitions:

Priority	Trigger	Condition	Target
1	On Tick	Has Target (TargetActor ← `Perception.TargetActor`)	→ Combat
2	On Tick	Is Suspicious (bIsSuspicious ← `Suspicion.bIsSuspicious`)	→ Investigate

Investigate State (Parent)¶

Transitions (apply to all children):

Priority	Trigger	Condition	Target
1	On Tick	Has Target	→ Combat
2	On Tick	Is Suspicious (bInvert = true)	→ Patrol

GoToStimulus (Default Child)¶

Task	Field	Bind To
AxM Move To	Controller	`AIController`
	TargetActor	`Perception.TargetActor`
	TargetLocation	`Perception.StimulusLocation`
	AcceptanceRadius	50.0

Transition: On State Completed → ScanArea

ScanArea¶

Task	Field	Bind To
AxM Look Around	Controller	`AIController`
	LookDuration	3.0

Transition: On State Completed → ScanArea (self-transition, loops until parent exits)

Combat State¶

Set the state type to Linked Asset and reference a combat sub-StateTree. The combat sub-StateTree owns both positioning (closing distance, finding cover) and abilities (attacks, cooldowns).

Parameter Bindings: The sub-tree receives data from the master tree's Global Tasks via parameters on the Linked Asset:

Sub-Tree Parameter	Bind From
`TargetActor`	`Perception.TargetActor`
`LastKnownLocation`	`Perception.LastKnownLocation`
`DistanceToTarget`	`TargetTracking.DistanceToTarget`
`HasLineOfSight`	`TargetTracking.HasLineOfSight`

Prototyping without a sub-StateTree

For quick prototyping, you can use the AxM Attack task directly instead of linking a sub-StateTree. Add AxM Move To + AxM Face Target + AxM Attack as tasks, and set a self-transition on State Completed. Replace with a linked sub-StateTree when you're ready to build proper combat behavior.

Transitions:

Priority	Trigger	Condition	Target
1	On Tick	Has Target (bInvert = true)	→ Search
2	On Tick	Is Outside Leash (DistanceFromHome ← `Perception.DistanceFromHome`, LeashRadius ← `Config.LeashRadius`)	→ Patrol

Search State (Parent)¶

Transitions:

Priority	Trigger	Condition	Target
1	On Tick	Has Target	→ Combat
2	On Tick	Is Outside Leash	→ Patrol

GoToLastKnown (Default Child)¶

Task	Field	Bind To
AxM Move To	Controller	`AIController`
	TargetActor	`Perception.TargetActor`
	TargetLocation	`Perception.LastKnownLocation`
	AcceptanceRadius	50.0

Transition: On State Completed → SearchArea

SearchArea¶

Task	Field	Bind To
AxM Search Area	Controller	`AIController`
	SearchCenter	`Perception.LastKnownLocation`
	SearchRadius	500.0 (or bind from Config)
	SearchDuration	10.0 (or bind from Config)
	AcceptanceRadius	50.0

Transition: On State Completed → Patrol

Property Binding Summary¶

Perception.TargetActor ──────┬──→ TargetTracking.TargetActor
                             ├──→ HasTarget conditions
                             ├──→ MoveTo.TargetActor (GoToLastKnown)
                             └──→ Combat Linked Asset → Parameters.TargetActor

Perception.HearingStrength ──→ Suspicion.HearingStrength

Perception.StimulusLocation ──→ MoveTo.TargetLocation (GoToStimulus)

Perception.LastKnownLocation ─┬─→ MoveTo.TargetLocation (GoToLastKnown)
                              ├──→ SearchArea.SearchCenter
                              └──→ Combat Linked Asset → Parameters.LastKnownLocation

Perception.DistanceFromHome ──→ IsOutsideLeash.DistanceFromHome

Config.LeashRadius ──→ IsOutsideLeash.LeashRadius
Config.PatrolWaitDuration ──→ Patrol.WaitDuration

Suspicion.bIsSuspicious ──→ IsSuspicious conditions

TargetTracking.DistanceToTarget ──→ Combat Linked Asset → Parameters.DistanceToTarget
TargetTracking.HasLineOfSight ──→ Combat Linked Asset → Parameters.HasLineOfSight