Unreal Engine Issues
Unreal Engine Issues
Niagara Mesh Renderer registers NumParticles x NumMeshVariants TLAS instances
UE - Rendering - Graphics Features - Ray Tracing - May 28, 2026When using the Niagara Mesh Renderer with multiple mesh variants selected via MeshIndex, the number of TLAS instances allocated is NumParticles × NumMeshVariants and enabling the Path Tracer can ca ...
FNiagaraRendererMeshes::GetDynamicRayTracingInstances(...) corrupting GPUScene when rendering multiple views
UE - Rendering - Graphics Features - Ray Tracing - May 20, 2026When rendering a game in splitscreen using Lumen HWRT, Nanite and a large number of Niagara Mesh Particles 1mil+, various meshes and actors will stop rendering. Setting r.RayTracing.Geometry.Niagar ...
Disabled Skeletal Mesh Sections cause Shadow Ray Tracing Flicker
UE - Rendering - Graphics Features - Ray Tracing - Dec 12, 2025If a skeletal mesh has a section disabled the ray traced shadow will flicker when the camera or itself moves. Previously in 5.6.0 no raytraced shadow would appear if a section was disabled. This wa ...
GetStaticRayTracingGeometries doesn't check if mesh has ray tracing disabled
UE - Rendering - Graphics Features - Ray Tracing - Nov 12, 2025An ensure is hit for static raytracing geometry because skeletal mesh assets that had ray tracing disabled were not handled in: FSkeletalMeshSceneProxy::GetStaticRayTracingGeometries The concurrent ...
5.6 Skeletal Meshes with Disabled Sections Flicker in Ray Tracing Scene
UE - Rendering - Graphics Features - Ray Tracing - Nov 7, 2025Skeletal meshes with disabled mesh sections will flicker in the Hardware Ray Tracing Scene. Also tested on //UE/Release-5.6, CL:45232827 ...
Uploading of the SBT via copy queue is not guaranteed to be synced with async compute queue but only direct queue in d3d12
UE - Rendering - Graphics Features - Ray Tracing - Oct 28, 2025When HitLighting is enabled, SBT commit is running on the Graphic Queue, and the pass "LumenSceneLighting->offscreenshadows->LumenDirectLightingHardwareRayTracingRGS" that uses SBT could run on the ...
Ray tracing scene doesn't reflect WPO with instance custom data
UE - Rendering - Graphics Features - Ray Tracing - Sep 19, 2025When custom instance data is used to calculate WPO in a Material and applied to an ISM the WPO value in the Lumen scene (ray tracing scene) is different than the visible scene resulting in incorrect ...
[CrashReport][GPUCrash] UpdateRadianceCaches
UE - Rendering - Graphics Features - Ray Tracing - May 19, 2025#31 crash out of 7783 in UE 5.7.4 on Windows#3 crash for UE - Rendering - Graphics Features in UE 5.7.4 on Windows#1 crash for UE - Rendering - Graphics Features - Ray Tracing in UE 5.7.4 on Windows ...
RayTracingManager::Tick() called twice in a single game frame
UE - Rendering - Graphics Features - Ray Tracing - May 14, 2025A licensee has shared a project with us, in which they are able to trigger a problematic case where the RayTracingGeometryManager is ticked twice during a single game frame. It would be good to inve ...
Opcode shader compilation error when using a TextureSampleParameterCubeArray node with hardware ray tracing enabled
UE - Rendering - Graphics Features - Ray Tracing - Mar 31, 2025Materials containing a cube array texture sampling node will not compile when hardware ray tracing is enabled. The shader compilation error indicates that an invalid op code was used: "Opcode Sample ...