Each bone scales are improperly applied in the physical animation

UE - Simulation - Physics - Character - Feb 4, 2025

Suggested fix from licensee is : PhysAnim.cpp@339 #if 0 FVector RelPos = RecipScale3D * RelTM.GetLocation(); #else FVector RelPos = (BoneIndex == 0) ? RecipScale3D * RelTM.GetLocation() : Rec ...

FLevelInstanceActorGuid::GetGuid issue in Multiplayer

UE - World Creation - Worldbuilding Tools - Level Instances - Feb 3, 2025

I am doing some runtime manipulation of data layers and I am running into a check failure due to a zero guid in FLevelInstanceActorGuid::GetGuid during multiplayer testing. When I debug FLevelInsta ...

Spline mesh crashing in FRayTracingDynamicGeometryCollection::AddDynamicMeshBatchForGeometryUpdate

UE - Graphics Features - Ray Tracing - Jan 31, 2025

A crash occurs when using ray tracing with spline meshes preceded by the following ensure : Ensure condition failed: NumCPUVertices <= VertexBufferNumElements  File: Engine\Source\Runtime\Renderer\ ...

Lumen ignores Landscape Holes (Landscape Visibility) when Hardware Ray Tracing is enabled and Ray Lighting Mode is set to Surface Cache

UE - Graphics Features - Ray Tracing - Jan 31, 2025

Context Lumen is the default global illumination and reflections system. Lumen renders diffuse interreflection with infinite bounces and indirect specular reflections in large, detailed environments ...

No warnings or errors if a UEnum has Bitflags metadata, but no Flags flag.

UE - Framework - Blueprint Compiler - Jan 29, 2025

The problem here isn't obvious: the native enum, EAnotherEnum, is missing the Flags flag for the UEnum. As a result, K2Node_GetEnumeratorNameAsString returns the max enum when it gets a combined fla ...

Bitmask ints can't be converted to strings

UE - Framework - Blueprint Compiler - Jan 29, 2025

While we do have an auto cast function that handles an int to string conversion, bitmask ints use a "bitmask" subcategory which thwarts are ability to find the cast function. ...

K2Node_GetEnumeratorName doesn't support bitmasks

UE - Framework - Blueprint Compiler - Jan 29, 2025

This is almost identical to [Link Removed]. The difference is that we need a variant of UEnum::GetNameByValue that supports bitmasks. We'll likely have to run this by Core. ...

In -game in Editor, if streaming-in a LevelInstance and initialize its world partition, then leaving that cell and make it go outside the streaming grid, to re-enter it again, will trigger a check(!StreamingPolicy) if no GC has happened during that time.

UE - World Creation - Worldbuilding Tools - World Partition - Jan 27, 2025

This crash can be fixed by adding a couple of || IsRunningGame() like it is done here:    FGenerateStreamingContext Context = FGenerateStreamingContext()        .SetLevelPackagesToGenerate((bIsPIE ...

UEditorEngine::AddPendingLateJoinClient checks original PIE/SIE state, not current state

UE - Networking - Jan 27, 2025

When adding late joining clients, the engine checks the originally requested EPlaySessionWorldType, rather than checking whether or not the session is currently simulating or not. This means if the ...

MRQ - Skeletal Mesh motion vector are output only for the last sample of Spatial Sample Count

UE - Anim - Sequencer - MRQ - Jan 24, 2025

Skeletal Mesh motion vectors are output only for the last sample of Spatial Sample Count, while Static Mesh motion vectors are output in all samples. UDN: [Link Removed] Slack thread: [Link Remo ...