Error during packaging if nativizing a blueprint that contains a TMap with a UserDefinedEnum as a key

UE - Gameplay - Blueprint - Jun 17, 2019

Certain Map container calls (e.g. Find, Add) will fail to compile at packaging time if a Blueprint class containing a Map variable with a user-defined enumeration as the key type is nativized. This ...

gltf 2.0 Blender Polly Import crashes

OLD - Enterprise - Aug 29, 2019

Trying to import the Polly sample model for gltf 2.0 crashes Editor. User know that the Plugin is experimental but as the Polly Model is used for Blender gltf development, it should work. The crash ...

Instanced static meshes fire an erroneous performance assert about loose parameters.

UE - Graphics Features - Sep 4, 2019

 "This ensure is intended to catch regressions where rendering programmers add a loose parameter to LocalVertexFactory, breaking dynamic instancing on regular static meshes.  InstancedStaticMeshes c ...

BP timelines: when converting internal curve to external, the external curve isn't used until BP is recompiled

UE - Framework - Blueprint Editor - Aug 28, 2023

Blueprint timelines: when converting an internal curve to an external curve asset, the curve asset's data isn't used until the blueprint is recompiled. This is confusing as there is no indication th ...

'GetClassDefaults' Can Cause Blueprint To Become Modified When Unrelated Blueprint Is Compiled

UE - Gameplay - Blueprint - Sep 22, 2023

The stems from a really old change (CL 2948683) to fix [Link Removed]. Compiling ObjectA will call RefreshExternalBlueprintDependencyNodes on its dependent BP,  ObjectB_ReferencesA, which reconstru ...

Clear Coat looks incorrect in the Preview when Energy Conservation on Material is enabled for non Substrate rendering

UE - Rendering - Architecture - Materials - Apr 11, 2024

Enabling Energy Conservation on Material makes Clear Coat Material look weird in Preview. It looks fine in the Level Editor, but not in any "Preview" type viewport (Material Editor, Asset Thumbnails ...

UAT crashing at end of build calling FScopedSceneLock_Chaos::LockScene()

UE - Simulation - Core - Nov 7, 2024

UAT has intermittent crashes at the end of  packaging. Looks related to  [Link Removed] . Could be that the solver is being destructed after the null check earlier in the function if this is multit ...

Substrate Unlit editor view mode renders black with Blendable GBuffer

UE - Rendering - Graphics Features - Substrate - Mar 18, 2026

When using Substrate materials with SUBSTRATE_GBUFFER_FORMAT==0 (Blendable GBuffer), the Unlit editor view mode renders completely black. TopLayerData.UnlitViewBaseColor is never populated in the bl ...

Material stats incorrectly flag 17/16 samplers even if GL4 allows 32

UE - Rendering - Architecture - RHI - Jul 15, 2015

From AnswerHub: Utilising 128 textures in a material does not work in Linux, its still limited to 16 (actual 12) on OpenGL platforms, I looked at the commit that implemented it and I don't see anyth ...

XAudio2 DestroyVoice call causes significant hitching on some architectures

UE - Audio - Aug 10, 2015

Another thread: https://answers.unrealengine.com/questions/241358/amd-cpu-very-low-performance-because-ixaudio2sourc.html Note: This not a regression and has existed since our first implementation ...