Unreal Engine Issues
Unreal Engine Issues
FMovieSceneSkeletalAnimationParams::MapTimeToAnimation returns the wrong value if InFrameRate is not the Tick Resolution
UE - Anim - Sequencer - Jan 16, 2026FMovieSceneSkeletalAnimationParams::MapTimeToAnimation takes in an FFrameTime and FFrameRate and is supposed to tell you which frame of animation that evaluates to, when accounting for looping, play ...
Light Function Materials containing a Texture Sample and Rotator nodes will fail RHI Validation
UE - Rendering Architecture - RHI - Jan 12, 2026Using 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 ...
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 ...
Velocity Scene Texture Data Integrity Issues
UE - Graphics Features - Jan 8, 2026When 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, 2026The problem is caused by FWaterViewExtension::ShouldHaveWaterZoneViewData that prevents the water data from being updated in SceneCaptures. (re: FWaterViewExtension::SetupView) Removing the call to ...
It is not possible to export virtual layer masks (AI or from mesh) through the COLMAP exporter.
RS - MVS - Jan 8, 2026Found 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 ...
Morph Targets fail to reset to zero
UE - Rendering Architecture - RHI - Jan 6, 2026"We have encountered a regression in UE 5.7 where Skeletal Mesh Morph Targets do not visually reset when all weights are set to 0.0. The mesh retains the deformation from the previous frame. This i ...
Out-of-Bounds Access During Partial Updates of ISMC Per-Instance Custom Data
UE - Graphics Features - Jan 6, 2026When using instance custom data values, removing an instance and changing the number of custom data floats in sequence can cause an array-out-of-bounds crash. The underlying arrays are not resized ...
CommonUI: FUITag, FUIActionTag variables can't connect with blueprint wildcard Equals node
UE - Editor - UI Systems - Jan 5, 2026Context UITag and UIActionTag are blueprint-exposed struct classes that derive from GameplayTag. GameplayTag variables can be compared in blueprint with ==. Under the hood, the node maps to UBlue ...
When r.SSR.Stencil is enabled, there is wrong logic observed.
UE - Graphics Features - Dec 19, 2025When r.SSR.Stencil is enabled, the areas with high roughnesss are not discarded and Unlit materials are incorrectly handled. See the linked EPS case (Additional Info URL) for a full explanation of ...