Assertion failed: Engine crushes when a geometry collection hits a landscape

UE - Simulation - Physics - Jul 27, 2020

This is because THeightField::PhiWithNormal has not been implemented yet. ...

Crash when destroying a geometry collection actor

UE - Simulation - Physics - Aug 7, 2020

When an actor with geometry collection is destroyed, the engine doesn't remove elements from array in the ChaosSolver So illegal references occurs. Removing element with following quick fix code ...

Calling RemoveAllAnchors function on a non-clustered geometry collection falls extremely fast

UE - Simulation - Physics - Destruction - Feb 8, 2023

Non-clustered geometry collections applied RemoveAllAnchors are not put into FPBDRigidsSOAs::DynamicGeometryCollectionArray, so acceleration is not reset every tick and they fall super fast. The fol ...

Fracture Mode > "Remove-On-Break" setting: Cluster Crumbling causes flickering

UE - Simulation - Physics - Destruction - May 10, 2025

Fracture Mode > "Remove-On-Break" setting: Cluster Crumbling causes flickering. Once the Remove-On-Break Cluster Crumbling effect is activated, there is a small delay between the disappearance of th ...

In a Geometry Collection, enabling Nanite Fallback in a Nanite Enabled collection won't generate a Physics Body when Nanite is disabled

UE - Simulation - Physics - Destruction - Jun 30, 2025

In a Geometry Collection, enabling Nanite Fallback in a Nanite Enabled collection won't generate a Physics Body when Nanite is disabled. To verify this, follow the steps provided in the Steps to Re ...

[AI] Crash when gathering heightfield geometry on worker thread

UE - AI - Navigation - Jun 25, 2025

From the body of the ticket: We aim to do as much of the work off the game thread as possible to avoid impacting frame rate. We've recently found a crash during collection of the geometry slices fr ...

Deadlock in UPhysicalAnimationComponent::UpdatePhysicsEngineImp

UE - Simulation - Physics - Sep 13, 2023

Deadlock in Chaos during PIE; the main thread is in USkeletalMeshComponent::HandleExistingParallelEvaluationTask waiting for a task to complete, and a worker thread is running that task and is in US ...

The AABBTree spatial acceleration structure goes off-sync when physics substepping is enabled in a "low" framerate environment.

UE - Simulation - Physics - Mar 15, 2024

When you enable the physics substepping, if you run the console command p.Chaos.Solver.DebugDrawSpatialAccelerationStructure 1, you can see how does not follow the physical object. The user that rep ...

Poor performance when Player Collision view mode active in City Sample

UE - Simulation - Debug Tools - Apr 2, 2024

The Editor become unresponsive and then has very low frame rates after activating the Player Collision view mode in the Small_City_LVL and Large_City_LVL maps in the CitySample project. The curre ...

Failed to build in Github UE4.27.0.

UE - Simulation - Physics - Aug 30, 2021

Failed to build UE4.27.0 with Win64/Development Editor.  Can avoid this error that excluding the project from build configuration. (Solution UE4->Properties->Configuration Properties->Configuratio ...