Lighting channels not working as expected when enabling Ray Tracing Shadow

UE - Graphics Features - Lumen - Oct 13, 2020

Non-Ray Tracing Shadows are only cast from lights on meshes assigned to the same Lighting Channel. When enabling Ray Tracing Shadows this is not the case. Lights will still cast Ray Tracing Shadows ...

Variant manager crash in UPropertyValue::HasValidResolve

UE - Editor - Content Pipeline - Variants - Nov 21, 2024

in the past we have reported a lot of VM related bugs which got fixed over time. Unfortunately, I think we have another one. Right now we're using 5.0.3 binaries from the launcher. Now the pro ...

Multiple setter functions in UMaterialEditingLibrary always return false even when the parameter is correctly set on the MaterialInstance.

UE - Rendering Architecture - Materials - May 30, 2025

In Unreal Engine, materials can expose parameters that can then be modified via instances (MaterialInstanceConstant). The UMaterialEditingLibrary provides several functions to modify these parameter ...

Creating a new C++ Synth Component results in a failed compile linker error.

UE - Audio - Dec 19, 2019

Upon creating a new Synth Component C++ Class in Unreal 4.24, the compiler will fail to compile with a Linker error. ...

Empty Shot Track Breaks Camera Component tracks when using Camera Cut Track

UE - Anim - Sequencer - Aug 18, 2016

Empty Shot Track Breaks Camera Component tracks when using Camera Cut Track ...

Physics object resting on movable platforms have erratic physics behavior in 4.14

UE - Simulation - Physics - Dec 14, 2016

Physics object resting on movable platforms have erratic physics behavior in 4.14. This is a regression from 4.13.2-3172292 User Description: When placing more than 10 or 20 blocks on a moving pl ...

[CrashReport] UEdGraphPin::Modify - UEdGraphSchema_K2::RecombinePin

UE - Gameplay - Blueprint - Sep 7, 2017

This is a somewhat common crash affecting users in 4.17. Users have not provided any descriptions of their actions when the crash occurred. Source Context 606 void UEdGraphPin::AddStructRe ...

Infinite Loop When Generating HLOD Clusters

UE - World Creation - Worldbuilding Tools - HLOD - Aug 8, 2018

The HLOD system gets stuck in a infinite loop when building.  Comment from the user: ++I've tracked it down to this code: const AActor* UHLODProxy::FindFirstActor(const ALODActor* LODActor) { a ...

Importing animation onto a camera in Sequencer adds extra keys to the scale and rotation attributes

UE - Anim - Sequencer - Oct 22, 2019

When importing non-baked animation (i.e. not keyed on every frame) onto a camera in sequencer, Unreal adds extra keys to the rotation and scale attributes as if it is baking the rotation and scale a ...

InstancedStaticMesh displaying corrupt lightmap data

UE - Graphics Features - May 17, 2021

I think I narrowed this issue down to bad UV coordinates being interpreted during the BasePassVertexShader execution applied to instancing. At this line in VertexFactoryGetInterpolantsVSToPS: flo ...