Unreal Engine Issues
Unreal Engine Issues
Translucent meshes randomly flicker when using VSM
UE - Rendering - Graphics Features - Jun 23, 2026Flickering can occur on translucent materials, usually in the distance when there is at least one directional light and when using VSM. Flickering seems highly dependent on framerate and timing. L ...
Non-Nanite meshes not being correctly cleared from all levels of VSMs on actor destruction when r.Shadow.Virtual.NonNanite.IncludeInCoarsePages=0
UE - Rendering - Graphics Features - Shadows - Jun 15, 2026When using the r.Shadow.Virtual.NonNanite.IncludeInCoarsePages=0 to optimize VSM performance there are errors in how the VSM is invalidated when actors are destroyed with non-Nanite meshes. The curr ...
Crash when applying Decal material with Distance Cull Fade node to Decal Actor
UE - Rendering - Architecture - Materials - Jun 15, 2026The Editor crashes when applying a Material with a Distance Cull Fade node to a Decal Actor. Fatal error: [Link Removed] [Line: 730] Missing uniform buffer at slot 2, stage SF_Pixel. Please check ...
check(bRenderStateCreated) fires in SendRenderDynamicData_Concurrent called from FRegisterComponentContext::Process
UE - Rendering - Architecture - RHI - May 18, 2026FRegisterComponentContext::Process() in ActorComponent.cpp iterates over SendRenderDynamicDataPrimitives and calls SendRenderDynamicData_Concurrent() on each. The existing guard checks ::IsValid(Pri ...
Wrong WPO motion vectors due to Periodic World Space node
UE - Rendering - Graphics Features - May 13, 2026We've noticed smearing in grass due to wrong motion vectors. This appears to be caused by lack of previous frame support in the periodic world space node. This is how we fixed it: In MaterialTempl ...
Curve Atlas Row Parameter uses derivative ops when Texture Sample connected to curveTime input
UE - Rendering - Architecture - Materials - May 1, 2026When a Curve Atlas Row Parameter node is used with a Texture Sampler connected to the curve time input, the sample type uses derivative ops. This has negative performance implications for Nanite co ...
When CommonTabListWidgetBase and ScrollBox are arranged vertically, tabs within CommonTabListWidgetBase momentarily become selected when scrolling the ScrollBox upward
UE - Editor - UI Systems - UMG - Mar 19, 2026When attempting to scroll the ScrollBox upward, the cursor briefly shifts focus to another widget (CommonTabListWidgetBase). When logging this behavior using LogSlate VeryVerbose, it can be observed ...
JsonObjectToUStruct removes _ClassName from input FJsonObject, breaking repeated deserialization
UE - Foundation - Mar 18, 2026FJsonObjectConverter::JsonObjectToUStruct removes _ClassName from nested JSON objects during deserialization. Removing Obj->RemoveField(ObjectClassNameKey) from ConvertScalarJsonValueToFPropertyWit ...
Cursor radius set via FSlateApplication::SetCursorRadius is ignored during FHittestGrid hit testing
UE - Editor - UI Systems - Slate - Mar 16, 2026The cursor radius configured through FSlateApplication::SetCursorRadius() is not respected during Slate hit testing. The radius value is correctly stored in FSlateApplication and passed into FHittes ...
UAbilityTask_SpawnActor::BeginSpawningActor may return true when SpawnedActor contains stale value
UE - Foundation - Mar 15, 2026UAbilityTask_SpawnActor::BeginSpawningActor assumes the incoming AActor*& SpawnedActor parameter is nullptr if no actor was spawned, but it does not initialize the parameter at the start of the func ...