Wrong calculation of "MaxAllocatedCountEstimate" inside FNiagaraRendererRibbons::GenerateDynamicData()

UE - Rendering - Architecture - Niagara - Mar 20, 2026

Starting with UE 5.4, function FNiagaraRendererRibbons::GenerateDynamicData() from file [NiagaraRendererRibbons.cpp] attempts to calculate DynamicData->MaxAllocatedCountEstimate as such: DynamicDat ...

Numerous LogMetal: Warning: AsyncCopyFromBufferToBuffer on overlapping ranges Warnings

UE - Graphics Features - Mar 13, 2018

Numerous LogMetal: Warning: AsyncCopyFromBufferToBuffer on overlapping ranges Warnings Warnings do not appear to be linked to any visual/performance problems in the editor. Could be safely ignored. ...

Foliage's Landscape Layers are not reflected when Landscape is rotated

UE - LD & Modeling - Terrain - Landscape - Feb 19, 2020

This problem seems to occur because Rotation is not taken into account when calculating Weight. I have confirmed that it can be solved by calculating the rotation as follows.float ULandscapeCompone ...

GetStaticRayTracingGeometries doesn't check if mesh has ray tracing disabled

UE - Rendering - Features - Ray Tracing - Nov 12, 2025

An ensure is hit for static raytracing geometry because skeletal mesh assets that had ray tracing disabled were not handled in: FSkeletalMeshSceneProxy::GetStaticRayTracingGeometries The concurrent ...

Crash when applying a LandscapeVisibilityMask material to a Landscape's material slot

UE - LD & Modeling - Terrain - Landscape - Apr 28, 2017

Crash that occurs when applying a masked material (with LandscapeLayerBlend and LandscapeVisibilityMask) to a Landscape's material slot. This is a regression: broken in 4.16.0 CL 3405315 worked in ...

Editing an instanced variable that is nested in two other instanced variables causes a crash

UE - Gameplay - Blueprint - Jul 2, 2015

If a user edits a instanced variable which is nested inside two other instanced variables in blueprint editor, a crash will occur ...

Changing LOD materials on Merged Actors Crashes Editor

UE - Gameplay - Sep 12, 2016

If you merg actors with LODs with the setting LODSelection Type set to "Use all LOD levels" then apply a material to the element 0 assigned to LOD1 the engine will crash. NOTE I wasn't able to rep ...

[CrashReport] UE4Editor_Engine!UAnimMontage::IsValidAdditive() [animmontage.cpp:702]

OLD - Anim - May 19, 2016

Error message: Stack overflow - code c00000fd (first/second chance not available) Source Context: 687 if (SyncGroup != NAME_None) 688 { 689 CollectMarkers(); 690 ...

Camera modifier blueprint used in another blueprint crashes editor (Assert failed in edit condition code in details panel)

Tools - Oct 14, 2019

Changing the default values inside of a camera modifier blueprint when referencing it in another blueprint results in a crash. Tested in 4.21, 4.22, 4.23 and 4.24 ...

Editor Crash with corrupted asset when opening within level or via the content browser.

Tools - Jan 5, 2017

Editor will crash when a skeletal mesh has been added to a level and then reopening the project later if you try and access this level. If you attempt to open the skel meshes in the content browser ...