Unreal Engine Issues
Unreal Engine Issues
Performance slowdown when ray tracing is disabled due to SetResidencyPriority
UE - Rendering Architecture - RHI - Jul 17, 2025When a game is compiled with ray tracing disabled (D3D12_RHI_RAYTRACING=0) and the GPU the game is running on becomes low on VRAM, frame time is negatively impacted and doesn't recover. The D3D12_RH ...
Sequencer - When a subsection has negative play rate, any nested sub-subsections fail to evaluate
UE - Anim - Sequencer - Jul 3, 2025Consider a sequence hierarchy with more than two layers. If the top-level sequence uses a negative timescale on a sub-sequence, the contents inside it animate as expected, but any nested sub-sequenc ...
Sphere Mask ArgInvHardness missing multiplication
UE - Rendering Architecture - Materials - Jun 27, 2025Hi Epic, In MaterialExpressions.cpp UMaterialExpressionSphereMask::Compile(), hardness is not calculated the same way in both <if> conditions. One is missing a multiplication by 0.01f. Specificall ...
TInstancedStruct used in native actor class loses reference to Instanced UObject after BP recompilation
UE - Foundation - Jun 25, 2025When a TInstancedStruct contains a UObject marked with EditInlineNew and DefaultToInstanced, the reference is lost after compiling the Blueprint but only when the struct is part of a native Actor cl ...
Eye Adaptation Inverse node does not work with volumetric materials
UE - Graphics Features - Jun 23, 2025The EyeAdaptionInverse node works differently for surface materials and volumetric materials. In surface materials, it allows to have a consistent glow during day and night time, however in a volume ...
Enabling bUpdateComponentTransformToRootBone in a GeometryCollectionComponent causes broken particles to appear in the wrong location
UE - Simulation - Physics - Destruction - Jun 22, 2025Enabling bUpdateComponentTransformToRootBone in a GeometryCollectionComponent causes broken particles to appear in the wrong location. When that flag is true, the moment the GeometryCollection (GC) ...
Crash when using StaticDuplicateObject with mismathced Source and Destination class types
UE - Foundation - Jun 19, 2025Starting in Unreal Engine 5.4, StaticDuplicateObject internally switched to using Unversioned Property Serialization (UPS) for performance reasons. However, UPS assumes the source and destination ob ...
Instanced Static Meshes ignore max World Position Offset Displacement for bounds after UpdateInstanceTransform is called
UE - Graphics Features - Jun 18, 2025When an Instanced Static Mesh Component (ISMC) uses a material with a non-zero Max World Position Offset Displacement, the bounds are correctly expanded at initialization. However, after calling Upd ...
Significant hitch occurs when invoking ApplySettings on a UGameUserSettings object
UE - Graphics Features - Jun 18, 2025Calling the ApplySettings method on a UGameUserSettings object results in a noticeable hitch, with severity proportional to the number of primitive components present in the scene. This hitch stems ...
Performance hitch from RemoveGeometryCache flushing the render thread
UE - Editor - Content Pipeline - Alembic - Jun 12, 2025FGeometryCacheStreamingManager::RemoveGeometryCache calls FlushRenderingCommands which shows up as a hitch when profiling. [Link Removed] Ideally the flush added in CL#23782411 to fix a rare deadl ...