Unreal Engine Issues
Unreal Engine Issues
Simulate motion vectors can fail on camera cuts
UE - Anim - Sequencer - Jun 11, 2024r.MotionVectorSimulation 1 should simulate motion vectors when cutting cameras, but this appears to be broken on some loops. ...
CreatePatchLibrary is broken
UE - Rendering - Architecture - Shaders - Nov 12, 2025It seems the FEditorShaderCodeArchive.LoadExistingShaderCodeLibrary missed some functions, use FEditorShaderCodeArchive.AddShaderCodeLibraryFromDirectory instead could fix the issue. ...
Megalights support for anisotropic materials
UE - Rendering - Graphics Features - Lumen - Apr 14, 2026A licensee noticed that SUPPORTS_ANISOTROPIC_MATERIALS is not passed to FShadeLightSamplesCS::ModifyCompilationEnvironment for MegaLights ShadeLightSampleCS. Adding it fixes the issue. ...
The visibility state of on-screen stat messages is not restored correctly after entering and leaving PIE. This also affects other important on-screen messages like map warnings and debug messages.
UE - Editor - UI Systems - Nov 28, 2024Currently, the ShowStats viewport option is automatically enabled when entering PIE and automatically disabled when exiting PIE. This forced disabling happens even if the option was enabled prior to ...
Jump Animation for FPS template character breaks on land
OLD - Anim - May 6, 2015When jumping in the first person template project, the "is in air" animation continues to play after landing. Solution: Switching out the "FirstPerson_JumpStart Asset" node for the "FirstPerson_J ...
FOV only Camera anim is not working as intended.
UE - Gameplay - Feb 6, 2018FOV-track-only camera anim do not give effect to current camera. if the anim have transform track without any key, the anim works. Regression? yes. This is not reproduced in 4.13.2 launcher version ...
Rect Light Texture does not unload during level streaming in packaged game
UE - Graphics Features - Jun 2, 2023UE5.6+ - Mutable - IDPrefix crash when combining Child Objects, Add to Mesh Component and Extend Mesh Section.
UE - Anim - Mutable - Jul 21, 2025So the issue seems to be a combination of Add To Mesh Component and Extend Mesh Section. I've tried this in Epic Launcher 5.6, 5.6 in-house modified engine as well as ue5-main 5.7 from git (editor ...
Local Exposure can cause large variations in PreExposure under certain conditions
UE - Rendering - Graphics Features - Sep 16, 2025PreExposure 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 ...
Contact shadow has box artifacts with backlighting for two sided Subsurface shading model
UE - Graphics Features - Shadows - Nov 14, 2023See slack channel: [Link Removed] ...