Unreal Engine Issues
Unreal Engine Issues
Translucent materials in the PostMotionBlur pass can cause a flickering viewport artefact when using TAA
UE - Rendering - Graphics Features - Feb 5, 2025There appears to be a bug relating to rendering multiple windows that can trigger under unknown circumstances. It has been reported on rectangle lights in the forums and on PostMotionBlur materials ...
UPlacementSubsystem does not respect AssetFactories priorities, which is inconsistent with UEditorEngine::ActorFactories and makes it impossible to override placed actor type when dragging asset from Content Browser to Level Editor Viewport.
UE - Editor - Workflow Systems - Mar 30, 2026Note: This issue was reproduced in UE 5.7, and it works correctly in UE 4.27. Prior to CL 24938100 (between UE 5.1 and 5.2), all existing factories were discovered and registered during engine init ...
Crash rendering image sequence if the Sub-Level with matinee is not loaded
Tools - Apr 15, 2016Crash rendering image sequence if the Sub-Level containing the matinee is not loaded. This seems to go away if the level is either set to "Always Loaded". Seems to be a result of people not switch ...
Crash when Previewing specific LODs within Static Mesh Editor at certain Screen Resolutions
Tools - Oct 27, 2016A crash occurs when attempting to preview specific LODs when the monitor resolution forces the menu to be expanded when selecting an LOD. This Jira was created from CrashReports submitted by the pu ...
[CrashReport] Assertion failed: Array index out of bounds - GetPhysicsTriMeshData() [modelcomponent.cpp:688]
UE - Simulation - Physics - Oct 30, 2017This is a semi-common crash that has occurred since at least 4.17.1. The callstack is nearly identical to [Link Removed], which was fixed in 4.18.0, however the error message and source context are ...
Crash Importing Skeletal Mesh LODs with a lot of morph targets
OLD - Anim - May 18, 2016Crash Importing Skeletal Mesh LODs with a lot of morph targets Error message: Assertion failed: (Index >= 0) & (Index < ArrayNum) [Link Removed] [Line: 785] Array index out of bounds: 2 from an ar ...
Velocity Scene Texture Data Integrity Issues
UE - Graphics Features - Jan 8, 2026When a Post-Process Material uses the Scene Texture Material Expression, the following code is generated: ``` MaterialFloat2 Local0 = Parameters.TexCoords[0].xy; MaterialFloat2 Local1 = ClampSceneT ...
[CrashReport] UE4Editor_Engine!FRepLayout::InitFromObjectClass() [replayout.cpp:2211]
UE - Gameplay - Blueprint - Apr 19, 2016This Jira was created from CrashReports submitted by the public due to the high number of occurrences. Descriptions from users are provided below. Error message: Assertion failed: Property->Proper ...
Crash retargetting AnimBP with "Allow remapping to existing assets" enabled
OLD - Anim - Aug 24, 20164.12 version of the crash: [Link Removed] Error message: Assertion failed: (Index >= 0) & (Index < ArrayNum) [Link Removed] [Line: 833] Array index out of bounds: 1 from an array of size 0 Sourc ...
Crash when casting to owner from AnimGraph
OLD - Anim - Sep 6, 2016Crash occurs when casting back to the pawn owner from the Anim Graph. In this case, it is being used for "Copy Pose from Mesh" Workaround: Cast to Owner from Event Graph, defining variable as the ...