Custom Primitive Data color widget not applying correctly to static mesh components in Blueprint editor.

UE - Rendering Architecture - Materials - Jul 23, 2025

Context Custom Primitive Data is used to store custom data in an index array that is accessible through Blueprint and code. This allows for variations across instances of the same mesh without needi ...

UMaterialFunctionInterface not being tagged as BlueprintType makes some editor scripting scenarios difficult

UE - Rendering Architecture - Materials - Jul 21, 2025

UMaterialInterface is BlueprintType, but UMaterialFunctionInterface is not. This makes it difficult to port some BP logic that works with materials to the material layer system. Crystal Dynamics wou ...

Inconsistent texture loading issue within material editor

UE - Rendering Architecture - Materials - Jul 16, 2025

A licensee has reached out via EPS about a texture loading issue they are having in-editor. I summarized the most important points below:The issue relates to texture load failure associated with mat ...

DistanceToNearestSurface node does not work when r.DistanceFieldAO is disabled

UE - Rendering Architecture - Materials - Jul 16, 2025

The problem seems to be that the bUsesGlobalDistanceField flag in the ShouldPrepareGlobalDistanceField() function checks for usage on the material, but it doesn't seem to take effect. The material u ...

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. ...

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 ...

Arrays in UMaterialEditorInstanceConstant are not updated

UE - Rendering Architecture - Materials - Jun 13, 2025

Any UPROPERTY TArray added to UMaterialEditorInstanceConstant will not cause UI updates when elements are added or removed. This is caused by the custom validator created in FMaterialInstanceEditor ...

Multiple setter functions in UMaterialEditingLibrary always return false even when the parameter is correctly set on the MaterialInstance.

UE - Rendering Architecture - Materials - May 30, 2025

In Unreal Engine, materials can expose parameters that can then be modified via instances (MaterialInstanceConstant). The UMaterialEditingLibrary provides several functions to modify these parameter ...

FHLSLMaterialTranslator::GetMaterialEnvironment can crash or not load UMaterialParameterCollections

UE - Rendering Architecture - Materials - Apr 30, 2025

In UE 5.5, the Editor may crash in FHLSLMaterialTranslator::GetMaterialEnvironment when loading materials with Material Parameter Collections, likely due to async loading. Calling ParameterCollectio ...

Crash when attempting to change the parent of a material instance constant through editor scripting

UE - Rendering Architecture - Materials - Apr 9, 2025

The built-in class "UMaterialEditingLibrary" provides various editor scripting functions related to creating and editing materials and material instances. One of these functions, UMaterialEditingLib ...