Unreal Engine Issues

If you use a transparent Material for one of the multiple materials, it will always show up in the raytraced reflection.

Raytraced translucency makes ExpHeightFog black

Does not occur in path tracing nor rasterized translucency. ...

Spline mesh can not cast shadow when raytracing enabled.

Crash using D3D raytracing with Support Ray Tracing unchecked static mesh

Static mesh that does not have Support Ray Tracing flag does not have a GeometryRHI object. So it causes a crash in FD3D12RayTracingScene. Excluding instances that do not have a GerometyRHI in FDef ...

Compilation error when using Particle SubUV in Niagara Mesh Particles with Raytracing enabled.

The licensee has shared the following workaround for modifying NiagaraMeshVertexFactory.ush. struct FVertexFactoryInterpolantsVSToPS { TANGENTTOWORLD_INTERPOLATOR_BLOCK #if USE_PARTICLE_SUBU ...

Raytracing Material Border Artefacts

Download the licensee repro from here - [Link Removed] The issue should be immediately visible in editor, but if not, shrink the main viewport and it should become more prominent as you zoom into t ...

SpiralBlur-SceneTexture Does Not Compile If Raytracing Enabled

The material function SpiralBlur-SceneTexture, does not compile in DX12 mode. Found in 4.22 CL# 7053642, 4.23 CL# 7321677, 4.24 CL #7474192 ...

Hidden Shadows Aren't Rendered When Raytracing Is Enabled

Hidden shadows aren't rendered when ray tracing is enabled. Found in 4.25 Preview 2 CL#12055273 Reproduced in 4.23.1 CL#9631420, 4.24.3 CL#11590370, 4.26 Main CL#12123513 ...

Raytraced Shadows don't render on landscape grass

Regression: Tested in UE5/Release-5.0, the issue did not occur so this is a regression Cast Dynamic Shadow should be enabled in the Landscape Grass Type by default, so shadows should be cast by the ...

RayTracing Final Gather is not working in UE 5.1

Further Comments: Customer is using the deprecated ray traced mode. ...