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 ...

Video material previews incorrectly on Mac

TM - Rendering - Apr 3, 2025

Received multiple reports of users on Mac computers experiencing issues previewing video materials in Twinmotion 2025.1. When adding video materials to the scene, the scale seems to be incorrect an ...

The AngularLimit visualizer isn't displayed as expected when adjusting the AngularRotationOffset

UE - Simulation - Physics - Dec 9, 2016

The AngularLimit visualizer isn't displayed as expected when adjusting the AngularRotationOffset. You can manually rotate the PhysicsConstraint and it will rotate the AngularLimit visualizer, howe ...

[CrashReport] UE4Editor_SlateCore!FSlateElementBatcher::AddElements() [elementbatcher.cpp:52]

UE - Editor - UI Systems - Slate - Nov 21, 2017

This is an infrequent crash coming out of the 4.18 release. Users have not provided any descriptions of their actions when the crash occurred. Based on affected project names, this may be a VR is ...

DrawDebugString display wrong position in PIE when changed display scale

Tools - Sep 16, 2020

The display position of the text in DrawDebugString is affected by the scale of the display. Should refer to the Project() of DebugCanvas (not Canvas). -  Suggest Code void AHUD::DrawDebugTextL ...

Edits of node properties that are not stored on pins do not diff correctly

UE - Gameplay - Blueprint Editor - Oct 2, 2015

Currently details changes to the following are not noticed by the Diff tool when diffing AnimBPs:State Machines (i.e. Max transitions per frame)Transition rulesConduitsStates This also affects non- ...

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 ...

Crash converting code project 4.7 to 4.8 ; Array index out of Bounds

UE - Gameplay - Blueprint - Jun 18, 2015

Some users are experiencing a crash when converting their project from 4.7 to 4.8. From user reports it appears to be affecting those who have added code to their projects and created blueprints bas ...

Unable to open UE4Editor on Linux - Bad hlslcc header found

UE - Platform - Linux - Nov 4, 2015

UE4Editor does not open on Ubuntu 15.10 due to the following error: [2015.11.04-16.19.35:974][ 0]LogOpenGLShaderCompiler:Error: Bad hlslcc header found! Missing '#'!Error in `./UE4Editor': free(): ...

Destructibles using Form Extended structures with rigid body collision gives wrong hit result

UE - Simulation - Physics - Destruction - Jan 7, 2015

DESCRIPTION: When using form extended structure with DMs that are hit by a rigid body the resulting hit does not reflect the correct actor if they are both using form extended. If a DM without form ...