Alpha Compression Artifacts

UE - Graphics Features - Nov 23, 2018

Confirmed in Main 4.22 @ CL 4586854 in 4.21 Alpha looks to be about 1 pixel larger than other channels in certain parts of the texture "The issue is not improved by changing compression settin ...

Unable to change Blueprint Child Variable values in Python

UE - Editor - Workflow Systems - Dec 20, 2018

Using the Python function unreal.SystemLibrary.set_bool_property_by_name() to change the default variable values of a child Blueprint do not work as intended. Tested in 4.20.3 (CL - 4369336), 4.21. ...

Launching a specific UDN Project with Vulkan Support enabled crashes launching on Quest

UE - Platform - XR - Jul 30, 2020

When attempting to run the attached Project submitted from UDN, it will crash on launch. If Vulkan support is disabled, the Project will run as expected on Quest. This issue DOES NOT appear to repro ...

Skelmesh Bake Materials doesn't remove old materials from slots

UE - World Creation - Worldbuilding Tools - Merge Actor - Mar 24, 2021

When an LOD get materials reduced to one with Bake Materials, it doesn't delete the extra slots on the LOD. So if starting with 10 slots on the skelmesh, then baking, slot 1 gets the newly baked mat ...

Static mesh components spawned in the UCS along a spline require lighting to be rebuilt after a map reload.

UE - Framework - Components - Jun 17, 2021

Seems to be somehow related to components being instanced in the Construction Script according to a spline. The transforms are slightly off by more than 1.e-2f. They are reconstructed on load with a ...

Perforce Version Control visually appears to allow deletion of locked files in Content Browser

UE - Editor - Workflow Systems - Nov 23, 2022

Repro Rate: 3/3 This issue was reproduced in //UE5/Release-5.1 at CL 23058290. This is confirmed to not be a regression since the error also occurs on the previous live version. This is regression ...

Baking lighting on Nanite landscape crashes the editor

UE - Graphics Features - May 23, 2024

When static lighting is baked using CPU lightmass for a nanite-enabled landscape it causes an editor crash with this assert: ...\Lightmass.cpp] [Line: 546] Attempting to add the same material twice ...

Additives using Frame From This Animation as the Base Pose Type fail to retarget correctly

UE - Anim - Rigging - Retargeting - Feb 13, 2025

Additive animations that use a frame from their own sequence as a base pose are initially broken when retargeted.  Users have to refresh the properties that select the base pose in order to fix the ...

DistanceToNearestSurface node does not work when r.DistanceFieldAO is disabled

UE - Rendering Architecture - Materials - Jul 16, 2025

The problem seems to be that the bUsesGlobalDistanceField flag in the ShouldPrepareGlobalDistanceField() function checks for usage on the material, but it doesn't seem to take effect. The material u ...

same PhysicsAsset refresh multi times when modify multi SkeletalBodySetup properties in same PhysAsset

UE - Simulation - Gameplay - Nov 20, 2025

USkeletalBodySetup::PostEditChangeProperty will call OwningPhysAsset->RefreshPhysicsAssetChange(), if I modify many SkeletalBodySetup properties in same PhysAsset, will cause call OwningPhysAsset-> ...