Unreal Engine Issues
Unreal Engine Issues
Temporal blur artifacts on Geometry Cache Components in Blueprint actor
UE - Editor - Content Pipeline - Alembic - Jan 9, 2026When a Geometry Collection is in a Blueprint, attached to other components, it can render incorrect motion vectors at some angles. In the test project, any angle that is not a multiple of 45 will re ...
GetAllocatedSize returns inaccurate number of bytes
UE - Foundation - Core - May 20, 2015When calling GetAllocatedSize() on a TBitArray it will round down the result of MaxBits / NumBitsPerDWORD. This means that not enough bytes are allocated when the MaxBits is not divisible by NumBi ...
Complex Collision as Simple causes odd Overlap behavior
UE - Simulation - Physics - Jan 25, 2016When triggering overlap events with a Static Mesh using Complex Collision as Simple, the overlap Begin and End events will be triggered rapidly in sequence. Changing to Default collision will fix t ...
Parent Begin Play node does not appear to run the parent code class BeginPlay() function before the rest of the Blueprint's Begin Play functionality
UE - Gameplay - Blueprint - Feb 19, 2015If a Blueprint event graph contains a Begin Play node that connects to a call to the parent function, the functionality present in the Blueprint Begin Play segment is run before the parent Begin Pla ...
Cloth rendering issue on triangles sharing kinematic attachments.
UE - Simulation - Physics - Character - Jul 29, 2020All render vertices on any cloth triangle that contains one or two fixed vertex are set as fixed, whereas this should only be the case if all three vertices were fixed. ...
Some post-processing passes sample outside of the viewport when using scene capture components
UE - Rendering - Graphics Features - Nov 29, 2023It looks like the SSAO shader does not clamp its sample space to the half view size for the two inputs "Ambient Occlusion" and "AmbientOcclusionSetup", leading to invalid data entering the edge of f ...
Calling DiscardPlayerInput() does not appear to actually discard the player's input
UE - Gameplay - Jun 19, 2018Calling DiscardPlayerInput() does not appear to actually discard the player input. The comment for the function indicates that input will be consumed and discarded without doing anything with it. Ho ...
bIgnoreAllPressedKeysUntilRelease behaves differently for triggers in EnhancedInputAction and triggers in InputMappingContext
UE - Gameplay - Input - Aug 10, 2023For actions that are triggered on the Input mapping context, simply adding or removing an InputMappingContext with no related key override with the bIgnoreAllPressedKeysUntilRelease option will caus ...
Physics constraint component doesn't work when placed inside a child actor, while using world partition and streaming is enabled
UE - Simulation - Core - Mar 21, 2025Context: In a World partition level, to reduce complexity and provide a scalable solution when creating new projects, grid cell streaming can be enabled. Problem: The problem is that physics constr ...
Chaos sometimes can not generate contact points while two dynamic convex hulls actually collide. It results in instability in the contact behavior - such as jittering, inconsistent contact forces, or unexpected collision responses.
UE - Simulation - Core - Dec 2, 2025Context: Chaos Physics is able to use convex hulls to represent object collision geometry for queries and simulation. Problem: Chaos sometimes can not generate contact points while two dynamic conv ...