FPS drop (present time increase) when moving the editor windows to secondary screens

UE - Rendering Architecture - RHI - Apr 29, 2022

The licensee has mentioned that they also see an FPS drop without a second monitor, so this can happen just by separating windows out on the same screen. ...

Lumen ignores Landscape Holes (Landscape Visibility) when Hardware Ray Tracing is enabled and Ray Lighting Mode is set to Surface Cache

UE - Graphics Features - Ray Tracing - Jan 31, 2025

Context Lumen is the default global illumination and reflections system. Lumen renders diffuse interreflection with infinite bounces and indirect specular reflections in large, detailed environments ...

Modifying the properties of a ChildActorComponent in a child blueprint can modify the parent actor ChildActorComponent properties.

UE - Framework - Blueprint - Dec 10, 2024

When a property of a ChildActorComponent is modified in a child class, the parent ChildActorComponent class can also get modified. This happens when the Parent blueprint actor has a ChildActorCompo ...

WasRecentlyRendered() and GetLastRenderTimeOnScreen() still triggers when a skeletal mesh re-enters the view frustum despite being occluded.

UE - Rendering Architecture - Dec 4, 2024

AActor::WasRecentlyRendered() and UPrimitiveComponent::GetLastRenderTimeOnScreen() both still trigger when a skeletal mesh (occluded behind a wall) re-enters the player's view frustum after being ou ...

CableComponent particles spawn at origin when gameplay starts depending on component registration order

UE - Framework - Components - Jan 9, 2025

A workaround was provided for the user, to use 'Set Attach End to Component' nodes during BeginPlay. While this fixes the issue in gameplay, the editor preview no longer syncs with gameplay. ...

Lumen indirect lighting artifacts when far from world origin

UE - Graphics Features - Lumen - Feb 6, 2024

Lumen seems to not be using Large World Coordinates somewhere. The Lumen Scene develops artifacts at large distances (5000 KM) from the world origin. ...

Distant mesh / vista have visible Lumen bounces

UE - Rendering Architecture - Jun 15, 2024

Objects far outside of the Lumen Scene don't temporally accumulate screen traces, leading to heavy flickering. It appears that the temporal reprojection is failing when comparing the depth in "Scree ...

Dithered LOD transitions do not work when the camera's field of view changes

UE - Graphics Features - Jun 12, 2025

Dithered LOD transitions do not work when changing the camera's field of view and cause artifacts when both the FOV and camera distance to the object are changed simultaneously. ...

When painting on a landscape with edit layers, there are UV distortions happening across the boundaries of paint layers when material is using SetMaterialAttributes

UE - Graphics Tools - Terrain - Landscape - Mar 10, 2025

Context Landscape Edit Layers enables users to paint landscapes using non-destructive layers, and can add multiple layers to the landscape that can be edited independently from each other. Problem ...