[Merge Actor] Lightmap UVs are broken after merging meshes

UE - World Creation - Worldbuilding Tools - HLOD - Jul 11, 2022

This issue occurs when merging static meshes that have multiple LODs. If they are using UV1 for lightmap index, after merging, the UV1 of the result for each LODs will all be differents, making the ...

Incremental Cooks: Add dependencies on files loaded during Load/Save of the package

UE - Foundation - Core - Cooker - Oct 19, 2022

Iterative and Incremental cooking are supposed to recook packages when their "inputs" change. Most of the time inputs are the package file itself and the other package files on which it has dependen ...

1 frame flickering when creating UMG using Textblock, ScaleBox and Overlay

UE - Editor - UI Systems - Slate - Dec 15, 2021

As a report of a similar issue, changing the text to right-aligned causes a similar issue. This issue seems to have been occur by a change in CL7540157. It also seems to be improved by adding the p ...

CookAdditionalFiles - WriteSharedFile function that allows multiple packages to generate the same file

UE - Foundation - Core - Cooker - Sep 23, 2022

Dependency on [Link Removed], which specifies that CookAdditionalFiles should take a context object. Keep the existing WriteAdditionalFile function that is an argument to CookAdditionalFilesOverrid ...

Create ini setting for DirectoriesToAlwaysStageAsUFSChunkRules to specify the chunks for UFS files.

UE - Foundation - Core - Cooker - Sep 23, 2022

Some plugins and projects are staging large amounts of AdditionalUFS files, and the only way to specify their chunk for streaming and optional install is using PakFileRules.ini. Add a setting in Ga ...

CookAdditionalFilesOverride Context struct

UE - Foundation - Core - Cooker - Sep 23, 2022

virtual void UObject::CookAdditionalFilesOverride allows non-package files to be copied or created during the cook whenever a UObject of your class is in a package that is cooked. This is useful for ...

Command buffer failure rates increased on iOS 15 devices compared to earlier iOS versions

UE - Rendering Architecture - RHI - Sep 23, 2022

There is a licensee report that command buffer failure rates on iOS 15 devices have increased compared to earlier iOS versions, and the issue may be related to foregrounding or backgrounding. ...

DistanceToNearestSurface used for post process broken when separate actor culled

UE - Graphics Features - May 27, 2021

This one may not necessarily be a bug, as this is related to the nature of culling. If it is not, please let me know if there is an alternative method the licensee could use here in order to track a ...

Groom bound to GeometryCache is unstable

UE - Editor - Content Pipeline - USD - Aug 10, 2021

This issue seems to occur only in 4.27 with DX12. Did not repro in 4.27 with -dx11, nor in UE5 DX11/DX12. ...