Physics — Chaos Engine

UE5 uses the Chaos Physics engine for rigid body simulation, destruction, cloth, and constraints.

📅 UE 5.4⏱ 18 min
Chaos Physics real-time destruction simulation in UE5
Chaos Physics destruction — a concrete pillar fractures in real time with per-chunk rigid body simulation and debris.

Rigid Body Physics

Enable physics on any Static Mesh Component by checking Simulate Physics in the Details panel. UE5 will resolve collisions, apply gravity, and integrate forces each frame using the Chaos solver.

Key properties on a physics-enabled component:

  • Mass — in kilograms. Affects impulse response and gravity force.
  • Linear / Angular Damping — resistance to movement; prevents infinite sliding.
  • Gravity Scale — multiplier on world gravity (default 1.0).
  • Enable CCD — Continuous Collision Detection for fast-moving objects.

Collision

Every physics-enabled object needs a collision shape. UE5 supports several presets via the Collision Preset dropdown and five base collision response channels: WorldStatic, WorldDynamic, Pawn, Visibility, Camera.

Collision PresetTypical Use
BlockAllSolid walls, floors — blocks everything.
OverlapAllTrigger volumes — overlaps everything, blocks nothing.
PhysicsActorSimulating rigid body — blocks WorldStatic/Dynamic.
PawnPlayer/NPC capsule — blocks WorldStatic, overlaps Triggers.
NoCollisionDecorative mesh — ignored by physics system entirely.

Physics Traces (Raycasts)

Line traces (raycasts) test for collisions along a ray. Use them for hit detection, line-of-sight checks, and ground detection:

C++ 
FHitResult Hit;
FVector Start = GetActorLocation();
FVector End   = Start + GetActorForwardVector() * 500.f;

bool bHit = GetWorld()->LineTraceSingleByChannel(
    Hit, Start, End,
    ECC_Visibility);

if (bHit)
    UE_LOG(LogTemp, Log, TEXT("Hit: %s"), *Hit.Actor->GetName());

Chaos Destruction

The Geometry Collection asset type enables real-time destruction. Fracture a Static Mesh in the Fracture Mode editor, then attach a GeometryCollectionComponent to an Actor. When a physics impulse exceeds the damage threshold, the mesh breaks apart into individually simulated chunks.

⚠️
Performance

Each destroyed chunk becomes a separate physics body. Limit simultaneous destructions to avoid CPU spikes. Use Chaos Cache to pre-record and replay destruction for cinematic scenes.

Physical Materials

A Physical Material asset defines surface behavior: friction, restitution (bounciness), density, and surface type. Assign it to a Material or directly to a collision shape. Surface types drive footstep sounds, particle effects, and decals via the Physical Material Response system.