Channel Mask Parameter does not correctly pull through the Alpha channel from

UE - Rendering - Architecture - Materials - Jul 8, 2025

The ChannelMaskParameter node in the Material Graph works in most cases, but unusually does not work when extracting the value of the Alpha channel only for Vertex Color input data. ...

Sequencer - When a subsection has negative play rate, any nested sub-subsections fail to evaluate

UE - Anim - Sequencer - Jul 3, 2025

Consider a sequence hierarchy with more than two layers. If the top-level sequence uses a negative timescale on a sub-sequence, the contents inside it animate as expected, but any nested sub-sequenc ...

CPU Lightmass generates different lighting results on a landscape if executed via a commandlet vs through the editor

UE - Graphics Features - Jul 3, 2025

Building lighting via commandlet and via editor are giving different results. To prevent one method from polluting the other via Swarm cache, the cache needs to be cleared in between tests. ...

Incorrect UV coordinates when visualizing mesh painting texutre on Nanite splines

UE - Rendering - Graphics Features - Jun 30, 2025

The UV coordinates for visualizing the mesh painting texture on Nanite spline meshes are not working correctly. This runs the code in the NANITE_VISUALIZE_MESH_PAINT_TEXTURE section in NaniteVisuali ...

Unwanted offset on curves when importing animation assets

UE - Editor - Content Pipeline - FBX - Jun 27, 2025

Hello, We seem to have encountered some unwanted behaviour when importing certain curves from our animation fbx assets into Unreal. Some of these curves don't have keys from the very first frame, b ...

Sphere Mask ArgInvHardness missing multiplication

UE - Rendering - Architecture - Materials - Jun 27, 2025

Hi Epic, In MaterialExpressions.cpp UMaterialExpressionSphereMask::Compile(), hardness is not calculated the same way in both <if> conditions. One is missing a multiplication by 0.01f. Specificall ...

Water Body Custom generates Map Check Warnings

UE - Graphics Tools - Terrain - Water - Jun 26, 2025

From licensee: Water Body Custom Actors generate this warning during Map Check: WaterBodyCustom_UAID_507C6F36B9215C5B02_1871778061 Static mesh actor has NULL StaticMesh property. To reproduce, si ...

TInstancedStruct used in native actor class loses reference to Instanced UObject after BP recompilation

UE - Framework - Blueprint Compiler - Jun 25, 2025

When a TInstancedStruct contains a UObject marked with EditInlineNew and DefaultToInstanced, the reference is lost after compiling the Blueprint but only when the struct is part of a native Actor cl ...

UAsset file size - fbx embedded textures

UE - Editor - Content Pipeline - Import and Export - Jun 20, 2025

hello! was curious if there were any settings I could adjust in Unreal to reduce the size of uassets generated from fbx files with embedded textures? i've recently swapped to using fbx exports from ...

Edit Condition does not work properly when the structure is used as a key for Map

UE - Framework - Blueprint - Jun 19, 2025

When the structure is used as a key for Map in Blueprint, Edit Conditions does not work properly. It will be updated when you move the focus to a different location(ex. a component) and click the v ...