Sequencer: Undoing creation of a new section can call section drawing code with viewmodel tree in invalid state

UE - Anim - Sequencer - Aug 1, 2024

The Section reference in ISequencerSection::GetSectionHeight can be in the process of garbage collection during an undo of a section addition- this causes things like GetTypedOuter<UMovieSceneTrack> ...

UE 5.4 - Specular/reflection disappears above 4096 resolution render

UE - Rendering Architecture - Aug 1, 2024

After a viewport is more than 4096 pixels wide, Lumen's specular reflections buffer cuts its width off at 4096 pixels. It appears that the affected buffer is "Lumen.Reflections.ResolvedSpecularIndi ...

Logic error in TRange::Difference causes crash when you Trim and Preserve Left/Right and unbounded Attach section in the sequencer

UE - Anim - Sequencer - Aug 1, 2024

TRange::Difference function does not handle bounds correctly, causes crash in the sequencer when "Trim And Preserve Left/Right" is used in the user's example project. User provided a potential fix: ...

Sequencer - Soft References do not work as payloads in Event Track keys, the endpoint event receives none/empty instead

UE - Anim - Sequencer - Jul 31, 2024

In sequencer, an "event track" can be added to call functions/events defined in the Sequence Director Blueprint. The parameters for those endpoint functions/events can be sent as a Payload associate ...

Landscape.Nanite.MaxSimultaneousMultithreadBuilds hangs indefinitely

UE - Graphics Tools - Terrain - Landscape - Jul 31, 2024

It's possible for NaniteStaticMeshesInFlight to never be decremented because all the background workers are waiting indefinitely for the ones in flight to complete their static mesh build.  ...

Disabling Disregard for GC with an invalid asset in GameplayTagTableList causes a controlled crash

UE - CoreTech - UObject - Jul 31, 2024

Disabling Disregard for GC leads to a crash in GarbageCollectionVerification.cpp VerifyObjectFlags. This crash occurs when there is an invalid path specified in GameplayTagTableList. The cause of t ...

Cooker: NeverCookPackageList should store packages as LongPackageNames instead of filenames, to save memory by avoiding creation of FName for each external actor package

UE - Foundation - Data Pipeline - Cooker - Jul 30, 2024

GetNeverCookPackageFileNames among other things adds every external actor package to NeverCookPackageList, even if they are not referenced by the rest of the cook. Since it stores the packages in th ...

Physics Linear Velocity functions from UPrimitiveComponent always return (0,0,0) velocity

UE - Simulation - Physics - Jul 30, 2024

In Unreal Engine version 5.4, all Physics Linear Velocity functions inside PrimitiveComponent class are returning always a velocity of (0,0,0), even if the Body Instances are moving. This was workin ...

FJsonPointer does not work and may lead to undefined behavior

UE - CoreTech - Jul 30, 2024

FJsonPointer::ParsePath passes a pointer to a single TCHAR as FString::ParseIntoArray's pchDelim parameter, which is supposed to be a pointer to a null-terminated string. ...

Error when zooming out in orthographic view in 5.4

UE - Editor - Jul 29, 2024

In 5.4: zooming out far with the mouse wheel after setting the editor viewport to orthgraphic view triggers an ensure: ensure(InOrthoZoom >= MIN_ORTHOZOOM && InOrthoZoom <= MAX_ORTHOZOOM); Th ...