Unreal Engine Issues
Unreal Engine Issues
HZB Occlusion causes large stalls on the render thread
UE - Rendering Architecture - RHI - Oct 7, 2025HZB 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 ...
Landscape Textures Patches issue when using "Texture Backed Render Target" as the Height Patch Source Mode where Landscape patches are not applying properly the first time a level is opened after restart
UE - Graphics Tools - Terrain - Landscape - Oct 6, 2025Context: Landscape patches are components that can be attached to meshes to affect the landscape as the mesh is repositioned. Problem: The problem is that when using "Texture Backed Render Target" ...
HZB occlusion is broken on Instanced Stereo
UE - Platform - XR - Oct 2, 2025Other engine features requiring HZB data (such as per-instance GPU LOD selection occlusion culling or light grid culling) are also impacted regardless of whether r.HZBOcclusion is enabled. ...
Values for InitialOnly replicated arrays can fail to be captured in replay when removed and re-added between checkpoints
UE - Networking - Oct 2, 2025When the first checkpoint is recorded, the correct array properties will be captured in the LifetimeChangelist. When these array items are later removed and another property on the actor is changed, ...
Failed to generate Nanite data for mesh with bDoFastBuild enabled
UE - Graphics Features - Nanite - Oct 1, 2025If "bDoFastBuild" is enabled on a Static Mesh asset, in-editor it will never be able to have Nanite data built for it, preventing the Static Mesh from using Nanite. There is no way to fix this issu ...
Pathtracer - Odd results from any material adjusting normals to complement world position changes
UE - Graphics Features - Path Tracer - Sep 30, 2025Someone on the forums is reporting a possible bug with Pathtracer and any material that adjusts normals to complement world position changes. See pic attached. Reporting forum thread:https://foru ...
Merge Actors (Simplify) is broken with Substrate Shader Models Node
UE - Graphics Features - Substrate - Sep 29, 2025Substrate Materials cannot be baked when Meshes are merged using the "Simplify" method. All textures except for the normal are reduced to a single black parameter. The normal texture produced does n ...
nDisplay Regression: Public header DisplayClusterViewport_OverscanSettings.h now includes internal header Math/MarginSet.h, breaking clients' code
UE - Virtual Production - nDisplay - Sep 29, 2025On the nDisplay plugin code, CL 44773085 from August 12 introduced a new struct template TMarginSet and changed struct FDisplayClusterViewport_OverscanSettings to use it. However, the latter is defi ...
DeltaCompressionBaselineManager needs to update its scope for minimal update
UE - Networking - Iris - Sep 29, 2025DeltaCompressionBaselineManager needs to update its scope for the case where objects may be replicated but no connections exist. ...