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Chest Mimicbrain

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

Overview​

Chest_MimicBrain implements the behavior tree logic for the chest mimic entity in DST. It orchestrates high-level decision-making using a priority-based behavior tree to handle states such as item collection, evasion (via hiding), wandering, and combat with players and other creatures. It integrates closely with timer, inventory, eater, knownlocations, and stategraph components, and it inherits from the base Brain class via BrainCommon.

Usage example​

This brain is automatically assigned to the chest mimic prefab during entity creation and is not typically added manually by modders. However, a modder might reference or extend it as follows:

-- Example of checking behavior state (not direct instantiation)
local mimic = TheSim:FindFirstEntityWithTag("mimic")
if mimic and mimic.brain then
    print("Mimic is currently", mimic.brain.bt and "active" or "inactive")
end

Dependencies & tags​

Components used: timer, inventory, eater, knownlocations, inventoryitem
Tags: Checks for busy (via inst.sg:HasStateTag), flight, jumping; uses no explicit tag additions/removals.

Properties​

No public properties.

Main functions​

OnStart()​

  • Description: Initializes the behavior tree for the mimic when the brain is activated (typically when the stategraph starts). Constructs a priority-based behavior tree with nodes for panic, hiding when inventory is full, and separate logic for non-jumping states including item collection, combat, and wandering.
  • Parameters: None.
  • Returns: Nothing.
  • Error states: May fail silently if dependencies like FindEntity or FindWalkableOffset return nil.

OnInitializationComplete()​

  • Description: Records the mimic’s initial position as "spawnpoint" using knownlocations. Used for navigation reference (e.g., when wandering).
  • Parameters: None.
  • Returns: Nothing.

Events & listeners​

None identified.

Helper Functions​

TryToHide(inst)​

  • Description: Attempts to generate an action to hide (transform back into a chest) by moving to a nearby walkable position. Only runs if the stategraph is not currently busy.
  • Parameters: inst (Entity) — the mimic entity instance.
  • Returns: A BufferedAction for ACTIONS.MOLEPEEK, or nil if conditions are not met or no valid position found.
  • Error states: Returns nil if FindWalkableOffset fails (e.g., no free space within radius).

FindGroundItemAction(inst)​

  • Description: Searches for and generates an action to pick up or eat a nearby ground item if the mimic’s inventory is not full and cooldown is inactive.
  • Parameters: inst (Entity) — the mimic entity instance.
  • Returns: A BufferedAction with ACTIONS.PICKUP or ACTIONS.EAT, or nil if no valid target or internal conditions block action.
  • Error states: Returns nil if inst.sg:HasStateTag("busy"), INTERACT_COOLDOWN_NAME timer exists, inventory:IsFull() is true, or no target passes the filter.

GetWanderPoint(inst)​

  • Description: Computes a target point for wandering: nearest player’s position (if any), otherwise the remembered "spawnpoint", or nil if neither exists.
  • Parameters: inst (Entity) — the mimic entity instance.
  • Returns: A Vector3 position or nil.
  • Error states: Returns nil if no nearest player and "spawnpoint" location is unset.