HZB Occlusion causes large stalls on the render thread

UE - Rendering Architecture - RHI - Oct 7, 2025

HZB Occlusion causes large stalls (greater than 5ms seen) on the render thread due to an RHI flush. This is caused by the following code in FDynamicRHI::RHIMapStagingSurface_RenderThread which force ...

Custom Depth range is different than Pixel Depth range

UE - Rendering Architecture - Shaders - Sep 25, 2025

Shaders that compare custom depth and pixel depth get wrong output values because the ranges are different. This error is most noticeable over large distances. The difference in ranges is due to t ...

Some operations on material instances do not transmit over transactions.

UE - Virtual Production - Tools - Multi-user - Sep 5, 2025

DirectoriesToAlwaysCook in platform specific configuration files are ignored by the cook process

UE - Platform - Console - Sep 5, 2025

When DirectoriesToAlwaysCook is placed in a platform-specific configuration file, the cook process does not read that entry when cooking content for that platform. The editor is aware of the platfo ...

GeometryCollectionPhysicsProxy::FieldParameterUpdateCallback() not removing invalid Commands, leading to performance issues

UE - Simulation - Visual - Aug 30, 2025

GeometryCollectionPhysicsProxy::FieldParameterUpdateCallback() not removing invalid Commands, leading to performance issues. The licensee has provided their analysis: We seem to have stumbled acro ...

Incorrect resolution used because SetProcessDpiAware() is not called when bAllowHighDPIInGameMode=False

UE - Rendering Architecture - Aug 8, 2025

The incorrect resolution is used on computers with 4k monitors that use DPI scaling (default 150%) because the default for UE projects is bAllowHighDPIInGameMode=False which results in SetProcessDp ...

Interaction between sublevels and LevelSequences can break actors attachments hierarchy of the sublevel.

UE - World Creation - Worldbuilding Tools - Aug 6, 2025

Having a LevelSequence opened and unhiding a sublevel can break the attachment hierarchy of the actors that are inside the sublevel. This also affects to the sublevel asset itself. ...

Anamorphic Squeeze Factor causes a blocky Depth of Field issue on AMD Hardware

UE - Graphics Features - Jul 30, 2025

When using the Anamorphic Squeeze Factor on a camera on AMD RDNA3 and RDNA4 hardware, blocking artefacts may be seen depending on the extent of the blur. The peripheries of the viewport appear to be ...

Unable to change Actor Coloration View Modes in PIE

UE - World Creation - Worldbuilding Tools - Jul 20, 2025

When in PIE changing Actor Coloration view modes from the viewport visualisation mode [Liit] -> [Actor Coloration] -> ... Does not update correctly when switching view mode and sometimes isn't corr ...

Performance slowdown when ray tracing is disabled due to SetResidencyPriority

UE - Rendering Architecture - RHI - Jul 17, 2025

When 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 ...