Unreal Engine Issues

Unable to override private Blueprint variables in child classes

In UE4, "Private" for Blueprint variables was misnamed: its behavior actually meant "Protected". In other words, it can't be read or written to by external objects, but it can be by derived types. A ...

USkeletalMeshComponent::HandleExistingParallelClothSimulation() calling WaitUntilTaskCompletes can trigger arbitrary task that modifies currently iterated UWorld::ComponentsThatNeedPreEndOfFrameSync

Context ActorComponents can schedule an end-of-frame update for themselves by calling UWorld::MarkActorComponentForNeededEndOfFrameUpdate. The UWorld will iterate all those actor components once pe ...

Physics Asset primitives are being created with the default Name as None instead of BoneName_PrimitiveType

When creating Physics Assets, either by automatic creation upon import, creation from skeletal meshes already in the project, or when we press Generate All Bodies (bottom right of a opened Physics A ...

Crash when exposing a TOptional<FName> or TOptional<FText> to the editor through a UProperty.

Support for editor-exposed uproperties of type TOptional<T> has been added by CL 28199740 on september 2023. However, since then until today in UE 5.5, a crash can happen when exposing TOptional<FNa ...

AutoSize triggers ensure on shortened Skel Anim Section moved past anim length

In Sequencer, calling "Edit > Auto Size" on a UMovieSceneSkeletalAnimationSection triggers the LowerBound > UpperBound ensure in UMovieSceneSection::SetRange (MovieSceneSection.h:333) when the secti ...

Orientation Warping breaks incoming poses where bones are in component space

The orientation warping node breaks incoming poses where bones are already in component space. This is because, in EvaluateSkeletalControl_AnyThread, we are repeatedly setting bone transforms direc ...

Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor

Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor. As described in the steps to reproduce, if we keep swapping bIsSpatiallyLoaded state and save a Streaming Level ...

Crash after generating HLODs for merged meshes that have all triangles culled

Crash after adding an AI Perception component to a parent and child character

Crash after adding an AI Perception component to a parent and child character. First they both must have had AI Perception components > Compiled and saved > Then both AI Perception components delete ...

[CrashReport] FPhysicsAssetEditorSharedData::FPhysicsAssetEditorSharedData

This is a trending crash coming out of the 4.18 release, and may be a regression. Users have not provided any descriptions of their actions when the crash occurred. Source Context 2290 #end ...