Unreal Engine Issues
Unreal Engine Issues
Brick Pattern Artifact in Volumetric Clouds
UE - Rendering - Features - Jul 28, 2026A licensee has reported seeing a repeating brick-like pattern in volumetric clouds when they overlap with very distant geometry (or at the transition between nearby and distant geometry). The artifa ...
VSM shadows are missing for non-Nanite meshes in a PPV where Megalights is disabled, but Megalights is enabled in the project
UE - Rendering - Features - Jul 14, 2026In UE 5.8 r.Visibility.LocalLightPrimitiveInteraction mode 2 (enabled if MegaLights is disabled) was added and made the new default as a performance optimization. However, this causes shadows to d ...
Translucent meshes randomly flicker when using VSM
UE - Rendering - Features - Jun 23, 2026Flickering can occur on translucent materials, usually in the distance when there is at least one directional light and when using VSM. Flickering seems highly dependent on framerate and timing. L ...
Issue with r.SkyAtmosphere.TransmittanceLUT.UseSmallFormat
UE - Rendering - Features - Mar 30, 2026When "r.SkyAtmosphere.TransmittanceLUT.UseSmallFormat=1", some values for the Sky Atmosphere at some directional light angles can lead to the sun disk being cut off, and taking on a chord shape. A ...
New material translator: Switch statement not derivative aware
UE - Rendering - Features - Jun 13, 2025Analytical Derivatives are not calculated properly when using UMaterialExpressionSwitch. Disjoint UVs in screen space result in large jumps in the derivatives, which can cause artifacts as the wrong ...
Collision Drawing in Cooked Builds (Development) doesn't Show Geometry for Nanite Meshes
UE - Rendering - Features - Jun 2, 2025Context The showFlag.CollisionVisibility 1 cvar is a viewport visualization mode that highlights which Actors will block visibility. The showFlag.CollisionPawn 1 cvar is a Player Collision viewmode ...
GPU ISM LOD uses bounds length instead of radius
UE - Rendering - Features - Jul 19, 2024When 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 ...