Unreal Engine Issues

Assert crash when playing Groom Cache with Card Mesh LOD

Playing a Guides Groom Cache while Card Mesh LOD (Guide-Based) is active causes an assert in RunHairStrandsInterpolation_Cards when the renderer switches to Card LOD. Assert location:Plugins/Runtim ...

VSM + Nanite Tessellation + Volumetric Fog Shadow leaking while the Directional lighting is rotating

ApplyLocalExposure uses Output_ExtentInverse instead of Output_ViewportSizeInverse for bilateral grid UV

The ApplyLocalExposureCS shader in PostProcessLocalExposure.usf computes UV coordinates for the LumBilateralGrid 3D texture using Output_ExtentInverse (1/RenderTargetSize) instead of Output_Viewport ...

Wrong WPO motion vectors due to Periodic World Space node

We've noticed smearing in grass due to wrong motion vectors. This appears to be caused by lack of previous frame support in the periodic world space node. This is how we fixed it: In MaterialTempl ...

Raytraced Hair Lighting using Light Functions atlas and positions the Light function material doesn't render correctly

Light functions don’t render on grooms when using ray traced shadows and positions in the light function material. The setup:A light (point/rect/spot) pointing to a groom hair system. The light's ...

Hair Shadows Not Affecting SSS Back Scattering (Subsurface Profile)

Groom strands do not appear to correctly block transmitted light for Subsurface Scattering Profile Materials. In some cases, not only will they not block the light, but can instead lead to more ligh ...

Issue with r.SkyAtmosphere.TransmittanceLUT.UseSmallFormat

When "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 ...

Crash when switching from Lumen visualization to raytracing visualization

When switching from Lumen visualization to raytracing visualization via the console, the editor can crash to desktop. The crash appears to happen deep within the driver libraries, and does not trig ...

Editor crash in HairStrandsMeshProjection.cpp when spawning actor with Groom Component bound to skeletal mesh

The editor crashes with an assertion failure when placing a Blueprint actor that contains a Groom Component bound to a MetaHuman skeletal mesh. The crash occurs in AddHairStrandInitMeshSamplesPass d ...

Material Editor Viewport does not display World Position Offset

The preview Viewport in the Material Editor does not correctly render World Position Offset. It appears that the RenderVelocities pass (which is also drawing the depth for the preview sphere) does ...