FStaticMeshCompiler::FinishCompilation stalls when compiling multiple meshes.

UE - CoreTech - Oct 7, 2024

Calling "FStaticMeshCompiler::FinishCompilation" on multiple assets simultaneously can cause a hang. Also tested on //UE5/Release-5.5, CL: 36784631 ...

Sequencer: Skeletal Animation with montages can cause blending issues when re-playing the same sequence on the same character

UE - Anim - Sequencer - Oct 1, 2024

The code in MovieSceneSkeletalAnimationSystem.cpp storages montage data on a per skeletal mesh component, per section basis. This (and a few other bits of logic) cause issues for external UDN user w ...

Invalid access location compressing a BC6h texture in the editor

RAD - Oct 29, 2024

Large texture crashes during Oodle compression with "-stompmalloc". It appears to be an internal Oodle error. Also tested on //UE5/Release-5.5/, CL: 37463908 ...

Light Function and World Position in 5.4

UE - Graphics Features - Nov 4, 2024

When rendering a Light Function into the Translucency Lighting Volume, the World Position Material Expression returns the position relative to the Camera (unrotated), not the World. This can be mor ...

Translucent light grid injection behavior

UE - Graphics Features - Nov 15, 2024

Light injection into the Translucent Light Grid voxels does not use the correct location for clipping or attenuation. Both of these points are outside the voxel that is being updated. Light attenua ...

Global SkyAtmosphere and Clouds Issues (Cloud Shadows)

UE - Graphics Features - Dec 3, 2024

Sampling Cloud Shadows when rendering the Sky Atmosphere can incorrectly assume that the view is located at the planet's North Pole. This causes distortion in the shadows when using a sphere-shaped ...

Global SkyAtmosphere and Clouds Issues (Ambient Light)

UE - Graphics Features - Dec 3, 2024

Ambient Light on Volumetric Clouds from Sky Atmosphere always is calculated as if the clouds are at the north pole of the planet. Using a sphere-shaped Sky Atmosphere and Volumetric Clouds causes t ...

Substrate SSR reflections are black

UE - Graphics Features - Substrate - Dec 17, 2024

Substrate Materials do not use Screen-Space reflections. Instead, they do not have any reflections (indirect specular) on the surface. ...

DMX component in world partitioned level fails cook

UE - Virtual Production - IO - DMX - Feb 10, 2025

Since UE5.5, RegisterComponent has been called during cook process, So unnecessarily references from DMXLibrary to DMXComponent has been added.  There is a workaround to avoid adding references : ...

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 ...