Light function does not work with volumetric fog when not compatible with light atlas

UE - Rendering - Features - Mar 28, 2025

Light functions do not work as intended with volumetric fog when using clamped mask textures which are not compatible with the light function atlas. In light functions materials, when using any UV ...

Adding a Scene Capture 2D to Render Target will override Motion Blur settings in level

UE - Graphics Features - Nov 24, 2014

With a Render Target From Scene Capture 2D setup in a level , the motion blur settings from a global post process volume is overridden. Was investigating Scene Captures picking up Motion Blur when ...

[Voice Virtualization][Focus] - Looping sounds do not become Virtual when Virtualization is Restart and Volume Attenuation is set to 0 by Focus settings

UE - Audio - Sep 2, 2021

When using Voice Virtualization settings, if the Attenuation Volume becomes 0.0 do to Focus setting, Restart does not behave as expected on looping sounds. Both Disabled and Play when Silent do wo ...

Custom Primitive Data color widget not applying correctly to static mesh components in Blueprint editor.

UE - Rendering - Architecture - Materials - Jul 23, 2025

Context Custom Primitive Data is used to store custom data in an index array that is accessible through Blueprint and code. This allows for variations across instances of the same mesh without needi ...

Temporal blur artifacts on Geometry Cache Components in Blueprint actor

UE - Editor - Open File Formats - Alembic - Jan 9, 2026

When 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, 2015

When 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 ...

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, 2015

If 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 ...

Some post-processing passes sample outside of the viewport when using scene capture components

UE - Rendering - Features - Nov 29, 2023

It 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 ...

Light Function and World Position in 5.4

UE - Rendering - Features - Nov 4, 2024

When rendering a Light Function into the Translucency Lighting Volume, the World Position Material Expression returns the position relative to the Camera (unrotated), not the World. This can be mor ...