Maya Generated FBX Files Fail to Import Properly into UE 4.10

Tools - Nov 24, 2015

The same animation FBX file generated from Maya will import correctly into UE4.9 but incorrectly into UE4.10. Moreover, if you generate an FBX from the animation that was successfully imported from ...

Problem with material layers using interpolator nodes

UE - Rendering Architecture - Materials - Jun 7, 2024

The Vertex Interpolator Material Expression appears to collapse separate instances from separate Material Layers, leading to visual artifacts when used. Also tested on UE5_Main, CL: 34200103 ...

[CrashReport] UE4Editor_SlateCore!FHittestGrid::GetBubblePath() [hittestgrid.cpp:145]

UE - Editor - UI Systems - Slate - Oct 27, 2017

This is a trending crash coming out of the 4.18 release. Users have not provided any descriptions of their actions when the crash occurred. Based on the affected project names, this crash seems co ...

uexp file of certain maps are always packaged when patching

UE - Foundation - Core - Nov 17, 2017

When generating a patch, (patch pak file) the .uexp file of the Editor Start Map and the Game Default Map are both packaged into the patch, even if another map is specified. Example: Editor Start ...

[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 - Voice Management - 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 ...

Orientation Warping breaks incoming poses where bones are in component space

UE - Anim - Gameplay - Apr 17, 2025

The orientation warping node breaks incoming poses where bones are already in component space. This is because, in EvaluateSkeletalControl_AnyThread, we are repeatedly setting bone transforms direc ...

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 - Graphics Features - 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 ...