Unreal Engine Issues
Unreal Engine Issues
Invalid GUIDs on new material instance parameters cause overrides to break on base param rename
UE - Rendering Architecture - Materials - Sep 3, 2025When a parameter value is assigned on a newly created material instance (constant or dynamic) using Set***ParameterValueInternal, the parameter’s ExpressionGUID is left invalid (0,0,0,0). Parameter ...
Precision issues with 16-bit Skin Cache shaders.
UE - Rendering Architecture - Sep 2, 2025A licensee reported precision issues with position in the gpu skin cache shaders with 16-bit real types enabled. ...
Negatively scaled box collisions render back faces in Player Collision debug view
UE - Simulation - Visual - Sep 1, 2025The player collision debug visualization for negatively scaled boxes is rendering the back faces, not the front faces. The debug primitives are rendered via the dynamic mesh builder. FDynamicMeshBui ...
Crash when running "MAP REBUILD ALLVISIBLE" with hidden sublevels and then changing maps
UE - World Creation - Worldbuilding Tools - Sep 1, 2025Running the MAP REBUILD ALLVISIBLE editor command when the current map contains hidden sublevels causes a crash upon changing maps. The issue seems to be related to hidden sublevels being cleared in ...
Hardware Lumen Surface Cache Artifacts on Nanite Geometry
UE - Graphics Features - Lumen - Sep 1, 2025When using Hardware Lumen with Nanite-enabled meshes in UE 5.6+, black / dark surface cache artifacts appear that result in generally darker and unstable lighting. These artifacts are not immediatel ...
GeometryCollectionPhysicsProxy::FieldParameterUpdateCallback() not removing invalid Commands, leading to performance issues
UE - Simulation - Visual - Aug 30, 2025GeometryCollectionPhysicsProxy::FieldParameterUpdateCallback() not removing invalid Commands, leading to performance issues. The licensee has provided their analysis: We seem to have stumbled acro ...
Crash When Loading Cooked Material Assets in Editor Due to Shader Serialization
UE - Rendering Architecture - Shaders - Aug 27, 2025In Unreal Engine 5.6+, the new shader serialization logic in FShaderMapResourceCode::Serialize does not correctly handle cooked assets that are loaded back into the editor (e.g., from a mounted .pak ...
UMG Retainer Box renders incorrect colors with Color Vision Deficiency enabled
UE - Editor - UI Systems - UMG - Aug 27, 2025When using a Retainer Box in UMG with Color Vision Deficiency enabled, the content inside the Retainer Box is rendered with incorrect colors compared to the rest of the UI. This bug is present in UE ...
Geometry Collection's Chaos Cache Static Pose Scrubbing broken in 5.6 due to Custom Renderer GeometryCollectionRootProxyRenderer
UE - Simulation - Physics - Destruction - Aug 26, 2025Geometry Collection's Chaos Cache Static Pose Scrubbing broken in 5.6 due to Custom Renderer GeometryCollectionRootProxyRenderer. The licensee has provided his analysis: In 5.6, when creating a Geo ...
Geometry Collection cluster handles leaking and causing ensures with field systems
UE - Simulation - Visual - Aug 26, 2025Geometry Collection cluster handles leaking and causing ensures with field systems. The licensee has shared their analysis: We have been tracking down an assert that seems to happen occasionally wh ...