Unreal Engine Issues

GPU ISM LOD doesn't take into account per instance scales when calculating LOD ranges

When we set up the draw calls for ISM with GPU LOD selection we submit a draw call per LOD. For this we calculate the minimum and maximum possible LOD with a call to ComputeLODForMeshes() in FReleva ...

GPU ISM LOD uses bounds length instead of radius

When calculating LOD for instances on GPU in NaniteCullingCommon.ush we use:float RadiusSq = length2(LocalBoxExtent); This doesn't exactly match the CPU logic for static mesh component LOD select ...

Scalebox scaling won't update if child size changes with global invalidation enabled

When global invalidation is enabled, Scale Boxes don't react properly to changes in the size of their contents. Licensees have worked around this by updating SScaleBox::OnArrangeChildren:// This sca ...

Windowed Fullscreen does not support multiple resolutions

UE5.4 Regression - crash when disabling shader optimization while raytracing is enabled on D3D12

Certain interactions between a Rect Light with a Light Function and a Post-Process volume lead to a check() when compiling a Ray Tracing PSO for tracing lights. This check() only happens when shader ...

Niagara compiler error, branch in custom hlsl doesn't work properly

Sandbox Visitors can fail on empty directories on non-Windows platforms

When a Sandbox Visitor checks a directory and it doesn't exist, it returns true on Windows and false on other platforms. The code that uses the result of this check, IterateDirectory, doesn't conti ...

'Max World Position Offset Displacement' causes culling issue on HISMC/foliage in 5.4

Foliage/hierarchical instanced static mesh components have issues with culling when their material's "Max World Position Offset Displacement" value is a higher amount, e.g. 100.0. ...

Incorrect behavior after attaching an actor to a non-root component of another actor in the Editor

UE allows actors to be attached to other actors. More precisely, it allows the root component of an actor (child) to be attached to any component of another actor (parent). From now on, "parent" and ...

GPU Lightmass does not support bounce lighting from landscapes

GPU Lightmass does not support bounce lighting from landscapes, but CPU Lightmass does. ...