Hidden Shadows Aren't Rendered When Raytracing Is Enabled

UE - Graphics Features - Lumen - Mar 13, 2020

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

UE - Graphics Features - Shadows - Nov 22, 2022

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

UE - Graphics Features - Ray Tracing - Apr 12, 2023

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

Random Scene Objects are not being rendered in Raytraced Reflections in packaging builds.

UE - Graphics Features - Lumen - Jun 11, 2019

Each time the build is run, different assets are missing in the reflections. Found in 4.22 CL# 6574378 and 4.23 CL# 6925347 ...

Editor/Game Ensure hit with RayTracing enabled on AMD GPU

UE - Graphics Features - Ray Tracing - Feb 4, 2025

A Static Mesh asset will trigger an ensure when generating building the ray tracing acceleration structure on AMD GPUs. ...

Crash when capturing attribute spreadsheet of Niagara GPU Particle with raytracing enabled

UE - Niagara - Jul 8, 2021

Also, NiagaraDebugger crashes the moment I enable GPU Particle Readback. ...

Light Leaking With Raytraced Shadows On Lights With Non-Zero Source Length

UE - Graphics Features - Ray Tracing - Jul 23, 2024

Light sources which have the source length attribute set to a value greater than zero seem to be leaking light through occluding geometry (see the image below and repro project). Moving it away from ...

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

UE - Rendering Architecture - Shaders - Jul 15, 2024

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 ...

Skylight mobility settings interfere with Ray Tracing accuracy

UE - Graphics Features - Lumen - Oct 28, 2019

When skylight raytracing is enabled, and skylight mobility is movable, skylight diffuse convolution is used on top of the skylight diffuse raytracing, causing severe bias and incorrect raytraced res ...