Unreal Engine Issues
Unreal Engine Issues
"DefaultToSelf" pin ignores parameter type
UE - Gameplay - Blueprint - Mar 5, 2015A user reported an issue resulting in a crash with callstack pasted below. After a brief investigation I've found that user was able to successfully compile a blueprint where a function taking an ...
Crashes after destroying a skeletal mesh attached via socket name (not bone name), the destroyed mesh remains welded.
UE - Simulation - Core - 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 ...
Static meshes with auto-generated LODs can no longer share lightmaps between LODs
UE - Graphics Features - Feb 21, 2017User report: With 4.15 using only auto generated LOD's static mesh LOD levels can't share computed lightmaps anymore. This cause severe memory increase and it's making lightmass build times way slow ...
Two Incompatible Object types are able to connect via add array in Blueprint Graph.
UE - Gameplay - May 21, 2019it is possible to connect two incompatible types to an Array Blueprint function node by connecting the Item pin first. The type of Array function nodes is determined by the first thing connected t ...
USplineMeshComponent::CalcBounds may return invalid value
USplineMeshComponent::CalcBounds function should be returning an FBoxSphereBounds type, but in the implementation it instead outputs an FBox. This may result in the returning of invalid results, esp ...
FNiagaraStackGraphUtilities::FindScriptModulesInStack() parameter "OutFunctionCalls" should be a reference
UE - Niagara - Aug 11, 2025On file [Engine\Plugins\FX\Niagara\Source\NiagaraEditor\Public\ViewModels\Stack\NiagaraStackGraphUtilities.h], function FNiagaraStackGraphUtilities::FindScriptModulesInStack() receives a parameter " ...
Multithreading Race Condition Crash with Anim Montages
OLD - Anim - Apr 2, 2015Basically, the problem is that the Main Thread is able to run AActor::Tick() (including Blueprint Tick Events) at the same time that the animation system is running functions such as UAnimInstance:: ...
Foliage instances don't move with a static mesh when it is shared between two foliage actors
UE - World Creation - Worldbuilding Tools - Foliage - Apr 26, 2023From Licensee: The bug comes from the call of the function `FoliagePartitioningUtils::Update` in the method `AInstancedFoliageActor::MoveInstancesForMovedComponent`. When the function `FoliageParti ...
Re-parenting blueprint actors do not lose interfaces associated with their previous parent blueprint
UE - Gameplay - Blueprint - Jul 23, 2015Re-parenting blueprint actors do not lose interfaces associated with their previous parent blueprint. Interfaces and interface functions can no longer be deleted from the re-parented actor. ...
UKismetStringLibrary::CullArray is poorly implemented
UE - Gameplay - Blueprint - May 18, 2017FString::CullArray is a static function, but the BP version is still taking a string instance to operate on (which it won't mutate as the function is static), and takes the array as an in/out argume ...