Unreal Engine Issues
Unreal Engine Issues
Arrays in UMaterialEditorInstanceConstant are not updated
UE - Rendering Architecture - Materials - Jun 13, 2025Any 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 ...
Nanite UV switch seams
UE - Graphics Features - Jun 13, 2025Analytical Derivatives are not calculated properly when using UMaterialExpressionSwitch. Disjoint UVs in screen space result in large jumps in the derivatives, which can cause artifacts as the wrong ...
Multiple setter functions in UMaterialEditingLibrary always return false even when the parameter is correctly set on the MaterialInstance.
UE - Rendering Architecture - Materials - May 30, 2025In Unreal Engine, materials can expose parameters that can then be modified via instances (MaterialInstanceConstant). The UMaterialEditingLibrary provides several functions to modify these parameter ...
Specular highlight and roughness issue on clearcoat material with second normal at certain view angles
UE - Graphics Features - May 21, 2025Specular highlights on non-Nanite meshes with a clearcoat material that has the second normal enabled will disappear at certain view angles. This can be worked around by adding a constant node to th ...
[CrashReport][Crash] UnrealEditor-Core!IMemoryReadStream::CopyTo()
UE - Rendering Architecture - Apr 10, 2025Intermittent crash in virtual texture transcode. Usually mempy from nullptr but also occasionally we see the same callstack with memcpy to random location. ...
WPO bug with Material Layers
UE - Rendering Architecture - Materials - Apr 7, 2025I find that there are a couple of things that influence the artefact If WPO in M_BlendingBug is connected I get an issue with the blending. Removing the opacity input that's passed through the ma ...
Reflection capture doesn't work when using Lumen GI and SSR
UE - Rendering Architecture - Mar 24, 2025Reflection Capture does not appear to work with Lumen + SSR. Licensees have reported that there are cases where they want to combine Lumen GI, SSR and Reflection capture for quality and performance ...
Sequencer: Skeletal Animation with montages can cause blending issues when re-playing the same sequence on the same character
UE - Anim - Sequencer - Oct 1, 2024The code in MovieSceneSkeletalAnimationSystem.cpp storages montage data on a per skeletal mesh component, per section basis. This (and a few other bits of logic) cause issues for external UDN user w ...
r.Shaders.Optimize=0 crashes when compiling a UI material
UE - Rendering Architecture - Materials - Sep 2, 2024[2024.08.30-22.12.22:384][ 73]LogWindows: Error: appError called: Assertion failed: CurrentGPUVirtualAddress != 0 [Link Removed] [Line: 659] Disabling shader optimisation can crash the editor when ...
UHapticFeedbackEffect_SoundWave Initialize does not populate Raw Data in the HapticsBuffer
UE - Platform - XR - Jul 19, 2024From the UDN: > Open HapticsFeedbackEffect.cpp and naivgate ~ line 150; note HapticBuffer has length populated but never write the actual buffer data. LikeReplySelect as Best Seems like a simple f ...