'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 ...

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 ...

Local Exposure can cause large variations in PreExposure under certain conditions

UE - Rendering - Graphics Features - Sep 16, 2025

PreExposure is influenced by LocalExposure in PostProcessEyeAdaptation.cpp:1265. It appears when the scene is particularly dark and using manual exposure, the LastAverageLocalExposure can read a lar ...

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 ...

Packaged projects do not render in web page using Safari 10.0

UE - Platform - Mobile - Aug 9, 2016

My Macbook Pro uses an Nvidia GeForce 750M and was on Safari 10.0 when this occurred. This did NOT occur on a Macbook Pro with the same card and using Safari 9.1.2. This did NOT occur on an iMac wi ...

User created widgets from widgets that are normally not focusable appear to break navigation when added to another widget even when focusable set to true

UE - Editor - UI Systems - Oct 28, 2016

User created widgets from widgets that are normally not focusable appear to break navigation when added to another widget even when focusable set to true Example: A widget with only a text block in ...

Crash occurs when importing attached FBX with default import settings

UE - Editor - Content Pipeline - Import and Export - Dec 22, 2016

While verifying a bug for 4.15 UE-39952 , I tried to repro in 4.14.2 and the editor crashed while attempting to import the attached FBX In 4.15, the Editor does NOT crash a window pops up stating t ...

Static Mesh Editor: Give options for drawing complex/simple collision

UE - Simulation - Physics - Mar 13, 2017

The collision mesh and the display mesh are often similar enough to be difficult to differentiate, and there is currently no way to view the collision wireframe without the display wireframe as well ...

Linux: Assertion at splash screen when trying to open UE4Editor

UE - Platform - Linux - Mar 21, 2017

I ran into this while looking to verify [Link Removed] at CL 3355923. I logged the issue I was verifying the fix for last night and have not updated anything locally, so the "OpenGL 4.3 not supporte ...

values for pinch input produce very different results for same area on android device

UE - Platform - Mobile - Oct 13, 2017

Values for pinch input produce very different results for the same area on an android device. values can range from 0 to 1, or end up in the thousands, despite the pinch distance being the same. It ...