Unreal Engine Issues
Unreal Engine Issues
[Niagara][5.8] Data Channel Read and Write register with an identical type hash when fx.Niagara.DataChannels.Enabled is set from ini, hitting checkf in FNiagaraTypeRegistry::RegisterTypeInternal
UE - Rendering - Architecture - Niagara - Sep 28, 2026Affects: 5.8 (verified on Release-5.8), Windows, EditorSummary Adding fx.Niagara.DataChannels.Enabled=true to an ini file makes the Niagara editor assert when a Data Channel Read is created. The sa ...
OverrideVertexColor causes a crash on mobile renderer
UE - Platform - Mobile - Graphics - Jan 8, 2026Setting Allow CPU Access on the mesh, or setting bSupportsManualVertexFetch=1 in Engine.ini, avoids the crash. ...
Not all MidPhases are enumerated in TSimCallbackObject::OnMidPhaseModification
UE - Runtime - Simulation - Dec 2, 2025Newly generated MidPhases are copied into the array accessible in the NarrowPhase after the OnPreSimulate callback is invoked. As a result, it is not possible to modify newly created MidPhases withi ...
Crash caused by a race condition in Nanite::DispatchBasePass()
UE - Rendering - Features - Nanite - Feb 25, 2026Nanite::BuildShadingCommands() launches two asynchronous tasks: ShadingCommands.SetupTask ShadingCommands.BuildCommandsTask BuildCommandsTask is responsible for modifying ShadingCommands.Commands ...
When very far out from the map origin, large static mesh is not streaming in until player is close in world partition even though it's within loading range.
UE - Engine Scaling - Streaming - World Partition - May 7, 2025Context World Partition has a distance-based level streaming system that provides a complete solution for large world management. Problem The problem is that when the player and large static mesh a ...
Inline retargeting gives different output pose vs retargeting from mesh
UE - ACT Character - Retargeting - Nov 19, 2025When we perform a retarget from an input pose rather than another mesh, the transforms within the anim bp have already been conformed to the target mesh by translational retargeting and compatible s ...
Legacy HLOD Nanite Meshes Always Rendering in 5.5
UE - Engine Scaling - Streaming - HLOD - Mar 17, 2025From licensee: We are using the legacy HLOD system in our game. With 5.5 there was a change to FSceneProxyBase::DrawStaticElementsInternal() where the implementation was removed (https://github.com ...
Resavepackages commandlet strips level package thumbnails
UE - Editor - May 12, 2026When loading thumbnails in FLinkerLoad::SerializeThumbnails, the level asset has two thumbnails. The first one has a size of 0, which causes the loading process to abort early. Since the actual thum ...
Missing UV Clamping or Clear in SunAlphaPS_Mobile
UE - Platform - Mobile - Graphics - Nov 13, 2025In: void SunAlphaPS_Mobile( float2 InUVs[8] : TEXCOORD0, in FStereoPSInput StereoInput, out HALF_TYPE OutColor : SV_Target0 ) { OutColor = SunUnBias(SunShaftAndDofTexture.Sample(SunShaftAndDo ...
StateTree: While editing State Parameters or exposed properties of a Condition/Task, an ensure() fires when editing inputs of a Property Function bound to an array element
UE - AI - StateTree - Mar 5, 2026Consider an array property that can be edited in the StateTree editor. This can be a State Parameter or an exposed property of a Condition or Task, for example. Each element of the array can be boun ...