Unreal Engine Issues

Screen Probes and Specular Firefly Flickering near screen edges

Lumen's rough specular indirect lighting buffer can have fireflies along the bottom and right edges of the screen. Also tested in //UE5/Main, CL: 35177423 ...

Crash when a subsystem calls GetSubsystemArray() on its owner while engine code is iterating on subsystems also obtained through GetSubsystemArray()

In some occasions, engine code iterates over a certain subsystem type by calling FSubsystemCollection::GetSubsystemArray() and then calling some method on all subsystems of the returned array. This ...

Pasting custom data floats from a text editor into a instanced static mesh component crashes the editor

When an instanced static mesh component with a material using a PerInstanceCustomData node has its data floats pasted in, the editor crashes with an "Array index out of bounds" error. The licensee w ...

Issue with Landscape Layer Blending Node compile in UE 5.4.2

When the SetMaterialAttributes Material Expression is used without an input to MaterialAttributes, it will cause Landscape Layer Blend expressions to fail to compile if it is the only layer on a par ...

Levels can get stuck in the 'loading' state when using Incremental GC

From licensee:"Testing incremental GC on our project we have ran into an issue with level streaming where levels will get stuck in the 'loading' state in packaged builds. The issue appears to be due ...

Foliage breaking when used Sublevels into a Persistent Level

Duplicating an imported socket wrongly displays the duplicate as also imported

The duplication of an imported mesh wrongly marks it as also imported from the source mesh. The probable cause is data duplication without taking this edge case into account. I suggest checking Unr ...

Landscape Transparent with r.Lumen.DiffuseIndirect.Allow 0

FILTER_COMMANDLINE_LOGGING cannot be used without forcing UE_COMMAND_LINE_USES_ALLOW_LIST

There's two ways to affect the commandline in CommandLine.cpp: FILTER_COMMANDLINE_LOGGING - for filtering certain or all args (if left empty) from the log. UE_COMMAND_LINE_USES_ALLOW_LIST - for on ...

HideBoneByName translates bone to parent which breaks skinning

Calling HideBoneByName on a bone causes that bone (and all it's children) to be translated to the parent bone's location.  This code in UpdateRefToLocalMatricesInner is responsible: bool bNeedToHid ...