Unreal Engine Issues
Unreal Engine Issues
Light Leaking With Raytraced Shadows On Lights With Non-Zero Source Length
UE - Graphics Features - Ray Tracing - Jul 23, 2024Light 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, 2024Certain 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 ...
RayTracing - Nanite Foliage assets do not display shadows properly when painted with Foliage Tool
UE - Graphics Features - Ray Tracing - Aug 18, 2025Skylight mobility settings interfere with Ray Tracing accuracy
UE - Graphics Features - Lumen - Oct 28, 2019When 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 ...
Crash occur when switching the Ray Tracing shadow function when only shadow is enabled in the Ray Tracing
UE - Graphics Features - Lumen - Sep 16, 2020According to the licensee, this problem is caused by a variable inconsistency in Cvar. The cause seems to be the difference between the CVar reference when generating RayTracingSceneRHI and the CVa ...
Raytraced Shadows render incorrectly in a project that has been converted from 5.0.3 to 5.1.1 to 5.2
UE - Graphics Features - Ray Tracing - May 16, 2023Version to VersionResultsNew 5.0.3 project to 5.1.1Works as ExpectedNew 5.1.1 project to 5.2Works as ExpectedNew 5.0.3 project to 5.1.1 to 5.2Bug OccursNew 5.0.3 project to 5.2 Bug Occurs The scene ...
Reflection captures cannot capture any ray tracing effects
UE - Graphics Features - Lumen - Aug 4, 2020Currently, Reflection capture ignore any ray tracing effects. So let'say you want to use only ray tracing shadow but also you want to use reflection captures for reflections instead of ray tracing r ...
Spline mesh crashing in FRayTracingDynamicGeometryCollection::AddDynamicMeshBatchForGeometryUpdate
UE - Graphics Features - Ray Tracing - Jan 31, 2025A crash occurs when using ray tracing with spline meshes preceded by the following ensure : Ensure condition failed: NumCPUVertices <= VertexBufferNumElements File: Engine\Source\Runtime\Renderer\ ...
VR Preview crash when shadow quality is set to low
UE - Platform - XR - Dec 5, 2024[/Script/Engine.RendererSettings] r.Tonemapper.Sharpen=2 r.TemporalAA.Upsampling=False r.DefaultFeature.AutoExposure.ExtendDefaultLuminanceRange=True r.LightPropagationVolume=0 r.ReflectionCaptureRe ...
Opening Sprite assets or Paper Flipbook crashes the engine in 5.3
UE - Gameplay - Paper2D - Apr 16, 2024Licensee was not able to open any Sprite asset file in 5.3 without it causing a crash. They were able to avoid this by disabling raytracing in the project. ...