Light Function Materials containing a Texture Sample and Rotator nodes will fail RHI Validation

UE - Rendering Architecture - RHI - Jan 12, 2026

Using a Light Function Material that contains a Texture Sample and Rotator nodes will cause RHI Validation to fail with the following error: LogOutputDevice: Error: Ensure condition failed: Bindings ...

Lumen Global Distance Field Trace Leaking due to Surface Cache Sampling

UE - Graphics Features - Jan 12, 2026

At specific distances from a thin wall, surfaces inside of a sealed chamber can receive indirect lighting from outside, leaking light into the chamber. This appears to be due to how SWRT handles sa ...

Temporal blur artifacts on Geometry Cache Components in Blueprint actor

UE - Graphics Features - Jan 9, 2026

When a Geometry Collection is in a Blueprint, attached to other components, it can render incorrect motion vectors at some angles. In the test project, any angle that is not a multiple of 45 will re ...

WP Builders: The Datalayer states forced in UWorldPartitionBuilder::LoadDataLayers can be lost

A licensee reported that Datalayers that are added to UWorldPartitionBuilder::IncludedDataLayers in a custom builder PreRun are not respected.   I used the minimap builder to debug the state of t ...

Not possible to force the Skeleton attribute to None on a default asset pipeline preset

UE - Editor - Content Pipeline - Import and Export - Jan 9, 2026

I guess that when the default value of the pipeline is None, the editor will silently pick the skeleton that is in the same folder of where you are importing. If the UI is active you can then force ...

Velocity Scene Texture Data Integrity Issues

UE - Graphics Features - Jan 8, 2026

When a Post-Process Material uses the Scene Texture Material Expression, the following code is generated: ``` MaterialFloat2 Local0 = Parameters.TexCoords[0].xy; MaterialFloat2 Local1 = ClampSceneT ...

WP: Water surfaces are missing from the Minimap textures.

UE - Graphics Tools - Terrain - Water - Jan 8, 2026

The problem is caused by FWaterViewExtension::ShouldHaveWaterZoneViewData that prevents the water data from being updated in SceneCaptures. (re: FWaterViewExtension::SetupView) Removing the call to ...

Inconsistent Behavior in TextureLODGroups when setting NumStreamedMips=0

UE - Rendering Architecture - Jan 8, 2026

A licensee has reported that it is not possible to disable texture streaming of a given TextureLODGroup by setting "NumStreamedMips=0" in their device profiles. Currently, using 0 results in the sam ...

It is not possible to export virtual layer masks (AI or from mesh) through the COLMAP exporter.

RS - MVS - Jan 8, 2026

Found in 2.1.0.119011 (R210). The mask export doesn't work even when the masks are regenerated from the mesh. Outcome: Error appears: "The filename, directory, or volume label syntax is incorrect ...

OverrideVertexColor causes a crash on mobile renderer

UE - Platform - Mobile - Jan 8, 2026

Setting Allow CPU Access on the mesh, or setting bSupportsManualVertexFetch=1 in Engine.ini, avoids the crash. ...