WorldCoordinate3Way produces Incorrect Axis Lerps

UE - Graphics Features - May 18, 2016

The Material Function WorldCoordinate3Way seems to incorrectly perform the Lerps from the axis contributions of the normals. An example is show here, with the left objects using the version that com ...

In UInstancedStaticMeshComponent, when some instances have near-zero scale, removing instances crashes the engine

UE - Rendering Architecture - Oct 19, 2023

Class "UInstancedStaticMeshComponent" deliberately leaves null pointers in the "InstanceBodies" array of FBodyInstances. This can be seen in methods such as: [Engine\Source\Runtime\Engine\Private\I ...

Misaligned sampling in UI Material with with CustomStencil

UE - Editor - UI Systems - May 19, 2025

The output of the CustomStencil node in a User Interface material does not align with the viewport dimensions. Toggling fullscreen/windowed mode (F11) causes the offset to reappear, so scaling the n ...

Spring Controller node rotation not working

OLD - Anim - Jan 31, 2019

The issue has been reported by one of our licensee. He proposed a patch to be applied in AnimNode_SpringBone.cpp 188,189c188,191 < FVector ParentToTarget = (TargetPos - ParentSpaceBase.GetLoca ...

Blueprint Array/Map properties with DefaultToInstanced types are not instanced properly

UE - Gameplay - Blueprint - May 6, 2019

At a licensee, I discovered a problem where Blueprint-created array and map properties are not correctly propagating the ContainsInstancedReferenced property flag. This means that if you create a Ma ...

Missing SmallOSAlloc/Free memory tracking with LLM on iOS

UE - Platform - Mobile - Dec 11, 2020

Licensee reports missing memory tracking for LLM on iOS: In Engine/Source/Runtime/Core/Private/HAL/MallocBinned.cpp in SmallOSAlloc, there is a compiler define for IOS and within it there is an LLM ...

The ChaosCacheManager changes the bSimulatePhysics flag from the ObservedComponents and, if deleted, the change will persist, what can lead to confusion as observed physical entities will inadvertently stop simulating physics

UE - Simulation - Physics - Nov 26, 2024

The ChaosCacheManager (CCM) changes the bSimulatePhysics flag from the ObservedComponents and, if deleted, the change will persist, what can lead to confusion as observed physical entities will inad ...

Physics Constraint doesn't hold if one Component is used for constraint

UE - Simulation - Physics - Jul 22, 2015

Physics Constraint doesn't hold if one Component is used for constraint User Description: Hello, I recently updated the project from 4.7.6 to 4.8.2 and the physics constraint don't seem to work an ...

Refraction Depth Bias In Material Instances Not Updating to Parent Materials Value

UE - Rendering Architecture - Materials - Aug 20, 2018

Refraction depth bias in Material Instances will not update to Parent Materials value. Found in 4.19 CL# 4033788, 4.20 CL# 4233996, and 4.21 CL# 4299102 Expected from user:Refraction Depth Bias sh ...

MaxChannels (Voices) is printed incorrectly to the Output Log on new projects

UE - Audio - Mar 16, 2022

The Max Channels (voices) setting displays in the output log as 0 on new projects. Likely a result of [Link Removed]. Issue is in display only (there are 32 voices), but should ideally report the de ...