Follow

Based on game build 714014 | Last updated: 2026-03-03

Overview

Follow is a behaviour node that enables an entity to dynamically adjust its position relative to a target entity. It maintains a target distance by either approaching the target when too far (APPROACH), backing off when too close (BACKOFF), or succeeding (idle) when within the desired range. The behaviour integrates with the locomotor component to execute movement and checks the target's health component to avoid pursuing dead entities. It supports dynamic distance thresholds via functions and platform-aware movement logic.

Usage example

local inst = CreateEntity()
inst:AddComponent("behaviourtree")
local follow_node = inst.components.behaviourtree:AddNode("Follow", inst, target_ent, 2, 10, 5, true, false, true)

Dependencies & tags

Components used: health, locomotor
Tags: None identified.

Properties

Property	Type	Default Value	Description
inst	Entity	—	The entity that will follow the target.
target	Entity or function	—	Target entity, or a function returning an entity.
min_dist	number or function	—	Minimum acceptable distance (below which entity backs off), or a function returning it.
max_dist	number or function	—	Maximum distance threshold (beyond which entity approaches), or a function returning it.
target_dist	number or function	—	Desired distance to stop moving (for success), or a function returning it.
canrun	boolean	true	Whether the entity is allowed to run instead of walk.
alwayseval	boolean	true	Whether distance functions are re-evaluated on every visit.
inlimbo_invalid	boolean	—	If true, fails if the target is in limbo (e.g., unreachable).
currenttarget	Entity	nil	Cached reference to the current valid target.
action	string	"STAND"	Current movement action (APPROACH, BACKOFF, or STAND).

Main functions

GetTarget()

• Description: Returns the current valid target entity, resolving self.target if it is a function, and verifying it is valid and not dead.
• Parameters: None.
• Returns: Entity or nil.

EvaluateDistances()

• Description: Recomputes min_dist, max_dist, and target_dist by evaluating any associated functions. Typically called when the target changes or alwayseval is enabled.
• Parameters: None.
• Returns: Nothing.

DBString()

• Description: Returns a debug string showing the current target, action, and Euclidean distance in meters.
• Parameters: None.
• Returns: string — formatted as "<target> <action>, (<distance>) ".

AreDifferentPlatforms(inst, target)

• Description: Determines whether the entity and target are on different platforms (e.g., ground vs. air), based on locomotor.allow_platform_hopping.
• Parameters:
  • inst (Entity) — entity to check.
  • target (Entity) — target entity.
• Returns: boolean — true if on different platforms and platform hopping is disallowed; otherwise false.

Visit()

• Description: The core behaviour node tick logic. Evaluates target presence, distance thresholds, and platform configuration to decide action (APPROACH, BACKOFF, or success). Executes movement via locomotor commands.
• Parameters: None.
• Returns: Nothing. Updates self.status (READY, RUNNING, SUCCESS, or FAILED).
• Error states:
  • Fails (status = FAILED) if target is nil, invalid, dead, or in limbo (when inlimbo_invalid).
  • Fails and stops locomotion if target becomes unreachable during RUNNING state.

Events & listeners

• Listens to: None identified.
• Pushes: None identified.
  (Note: Event handling is delegated to the behaviour tree framework and locomotor, not directly fired by this component.)