Unreal Engine Issues

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

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 ...

GeometryCollection clustered by ClusteredGroupIndex does not respect child's gravity setup

Following code works as a workaround void FClusterUnionManager::HandleAddOperation(FClusterUnionIndex ClusterIndex, const TArray<FPBDRigidParticleHandle*>& Particles, bool bReleaseClustersFirst) ...

Nanite enabled Geometry Collection is not simulated by ChaosCache in package application

When using ChaosCacheManager to simulate destruction of a GeometryCollection, destruction is not simulated when Nanite is ON for the GeometryCollection. In the editor, destruction is simulated rega ...

Chaos Clothing CreateClothActor takes a long time with LODs and Self-Collision

Spawning an actor with Chaos cloth causes a hitch when LODs or Self-Collision are enabled on the cloth. LODs and Self-Collision seem to compound the issue. Self-Collision requires a collision simul ...

UnregisterAsyncPhysicsTickActor not being called when actors end play via UWorld::RemoveFromWorld

Motion vectors not generating correctly in build

Also tried using “show VisualizeTemporalUpscaler” and noticed the frames that have missing motion vector data showed up as pops in the “show VisualizeReprojection” part of the visualizer. ...

Collision between physicalized actors and instanced static meshes produce warnings.

Collision between an instanced static mesh and a physics simulating actor (with "simulation generates hits events" enabled) results in the following warning: LogChaos: Warning: Collision handler en ...

Spherecast against complex geometry is returning odd results

Turning on batching of sphere casts when colliding against complex gives incorrect results. Affects debug output and vehicle wheels and body movement. The issue is with the batch query mode which ...

Free physics constraints between two objects of differing size causes smaller object to jitter

A cube constrained to a physics actor will start to jitter uncontrollably when interacted with. (see attached media and repro steps for more details) Tested in the following //UE5-Release-5.3-CL ...

When change a skeletal's collision from QueryOnly to QueryAndPhysics at runtime, dynamic properties won't be updated

It seems in the FBodyInstance::InitDynamicProperties_AssumesLocked, we early out when the body instance's collision is QueryOnly, but actually we only recreate its physics state when changing from N ...