---
title: Chaos Destruction Overview
source: https://docs.unrealengine.com/4.27/en-US/InteractiveExperiences/Physics/ChaosPhysics/ChaosDestruction/ChaosDestructionOverview/
version: Unreal Engine 4.27 Documentation (UE5 slug chaos-destruction-in-unreal-engine is only an index page; overview page not found for 5.x)
fetched: 2026-10-11
note: 原文摘录（英文要点），供 wiki 引用；非全文
---

# Chaos Destruction Overview

- System relies on Geometry Collections (what), Fracturing (how), Clustering (levels to break apart); plus Connection Graph (how fractured pieces are connected) and Fields (directly interact with/control pieces).
- Collision: Implicit Type Analytic (box/sphere/capsule; fast, low memory, less accurate; may start intersecting) vs Level Set (voxelized signed distance field; accurate, memory scales cubically).
- Clustering: Auto Cluster groups pieces into Fracture Levels; typically few large clusters at Level 1, smaller pieces at higher levels — "For optimization, you might not want thousands of pieces on the initial break, but instead, have individual pieces break off as the building is coming down." Max Cluster Level limits breakage depth. GeometryCollection.PrintDetailedStatistics(Summary).
- Damage Threshold per Actor: "how much strain is required for each successive Level to break". Descending thresholds through ascending levels; "as clusters fall down, the collisions will lower their velocities. This means that lower thresholds are needed to ensure that smaller pieces break down even more."
- Cluster Group Index: actors with same index behave as Level 0 together; Field data shared. Collision Particles Fraction: too low → wrong collisions (rolling through floor).
- Fields: Field System Actor Blueprint + Field System Component. Add Field Command in Construction (before simulation, e.g. Anchors); Apply Physics Field during simulation (External Cluster Strain explosions). Types: DynamicState (Sleeping/Kinematic/Static/Dynamic), LinearForce, ExternalClusterStrain ("values greater than the Geometry Collection's Damage Threshold will release clustered pieces"), Kill, LinearVelocity, AngularVelocity, AngularTorque, InternalClusterStrain, DisableThreshold ("Disabled rigid bodies are completely removed from the simulation... can be reactivated by fields (not collisions)"), SleepingThreshold ("can be woken up... by Fields and Collisions"), DynamicConstraint, CollisionGroup, ActivateDisabled.
- Anchor Fields must be in Construction Script via Add Field Command "since the connection graph must also be established prior to simulation"; anchored collection stays static until Strain applied.
- Sleep vs Disable: disabled cannot be reactivated by collisions, "very cheap during simulation". With Disable/Sleep/Kill fields "it is critical that you apply culling outside of it" or they stomp other fields. Internal strain + noise for collapsing over time.
- Caching: record (Cache Mode Record) then Kinematic + Play for background destruction; removes runtime cost/hitch; Sequencer playback.
- Custom Chaos Solver actors to distribute load. Niagara Chaos Data Interface: collision/breaking/trailing events. Gameplay: Notify Breaks/Notify Collisions, OnChaosBreakEvent (component, location, velocity, mass), OnChaosPhysicsCollision; spawn field at impact location.