Unreal Engine Issues
Unreal Engine Issues
Negatively scaled box collisions render back faces in Player Collision debug view
UE - Simulation - Physics - Sep 1, 2025The player collision debug visualization for negatively scaled boxes is rendering the back faces, not the front faces. The debug primitives are rendered via the dynamic mesh builder. FDynamicMeshBui ...
Destroying a welded actor is causing an Array index out of bounds crash on 5.6
UE - Simulation - Physics - Jul 30, 2025Destroying a welded actor is causing an Array index out of bounds crash on 5.6. The licensee has provided a repro project that reliably causes a crash whenever the spawned actor is destroyed. There ...
Typo in GetAsBoundsArray() from file AABBTree.h on Chaos module
UE - Simulation - Physics - Jul 30, 2025From file [Engine\Source\Runtime\Experimental\Chaos\Public\Chaos\AABBTree.h], function Chaos::TAABBTree<>::GetAsBoundsArray(): bool GetAsBoundsArray(TArray<TAABB<T, 3>>& AllBounds, int32 NodeIdx, i ...
The Geometry Collection Dataflow node CreateGeometryCollectionFromSources is breaking Material Assignment
UE - Simulation - Physics - Jul 21, 2025The Geometry Collection Dataflow node CreateGeometryCollectionFromSources is breaking Material Assignment. As the licensee has pointed out, this previously worked in 5.5. The most probably cause fo ...
Enabling Strip Source Data On Cook on Geometry Collection is also stripping the Anchor flag of cooked assets
UE - Simulation - Physics - Jul 20, 2025Enabling Strip Source Data On Cook on Geometry Collection (GC) is also stripping the Anchor flag of cooked assets. The licensee has reported that once they do a build the Anchors disappear and GCs t ...
Crashes after destroying a skeletal mesh attached via socket name (not bone name), the destroyed mesh remains welded.
UE - Simulation - Physics - Jul 18, 2025On welding physics bodies during primitive component attachment, UPrimitiveComponent::WeldToImplementation() calls GetRootWelded() and then GetBodyInstance() on the returned root. This searches by b ...
Soft angular constraints solve velocity like hard constraints
UE - Simulation - Physics - Jul 17, 2025Soft angular constraints are solving velocity like hard constraints. Instead of swinging back and forth, the affected body just snaps to 45 degrees. Check the steps to reproduce for more details. Th ...
In AnimNode_RigidBody.cpp, PhysicsSimulation->CreateActor() is being passed World Space transforms, when it should be getting Local Simulation space transforms
UE - Simulation - Physics - Jun 24, 2025In AnimNode_RigidBody.cpp, PhysicsSimulation->CreateActor() is being passed World Space transforms, when it should be getting Local Simulation space transforms. The licensee has reported that FAnimN ...
Unexpected Collision Response When Nesting Primitive Components with auto-weld enabled and physics disabled on children. The root primitive falls through floor even though it is set to block all.
UE - Simulation - Physics - May 27, 2025Context Auto-weld makes it so if a child is attached to a parent, the two bodies will be joined into a single rigid body. Physic settings like collision profile and body settings are determined by t ...
ChaosWheeledVehicleMovementComponent is breaking the const CDO contract and changes to the instances are being applied to the CDO
UE - Simulation - Physics - Apr 28, 2025As described by the licensee, the const CDO contract is being broken on ChaosWheeledVehicleMovementComponent. The issue the licensee is facing is that by spawning cars with different configurations, ...