GPU Scene reserved resources can break Niagara mesh preview rendering

UE - Rendering - Architecture - Niagara - Sep 28, 2026

When a Niagara emitter has multiple Mesh Renderers and each renderer draws a different subset of particles (via Renderer Visibility), all renderers are drawn using the color of particle index 0 in t ...

Does FSlateElementBatcher::AddCachedElements need to check if r.HDR.UI.CompositeMode is enabled?

UE - AI Workflows - UI Systems - Aug 28, 2024

When a specific configuration of HDR cvars are set, PIE in a New Editor Window will not render the game world. Settings (For DefaultEngine.ini): ```[SystemSettings] r.AllowHDR=1 r.HDR.Display.Color ...

Light Function and Post Process domain material thumbnails show the default material

UE - Rendering - Architecture - Materials - Sep 25, 2026

Since 5.8, materials whose Material Domain is Light Function or Post Process no longer preview correctly in the editor. They render as the default material (WorldGridMaterial) instead of the materia ...

Controller Mapping/Unmapping on some platforms is not ideal for local multiplayer

UE - Gameplay - Input - Nov 19, 2025

[Link Removed] The workaround is as I posted in the UDN, to override the viewport client or to make a custom slate input mapping to change this behavior. But, there is a bug with that unmapping/l ...

Interchange GLTF importer truncates skeletal mesh bone influences to 4 per vertex

UE - Editor - Open File Formats - Aug 21, 2026

cf https://forums.unrealengine.com/t/interchange-gltf-importer-truncates-skeletal-mesh-bone-influences-to-4-per-vertex/2745391/2 Original message The UE5 Interchange GLTF importer appears to trunc ...

The Remove-On-Break feature, set on Fracture Mode on Geometry Collections, stops shrinking and shows strange behaviors

UE - Runtime - Deformable - Oct 15, 2024

The Remove-On-Break (ROB) feature, set on Fracture Mode on Geometry Collections (GC), was supposed to make the particle shrink until it vanishes. When the GC goes to sleep the shrinking stops and sh ...

A GeometryCollection that was broken and is going through shrinking will reset the size of its particles if a second level is broken

UE - Runtime - Deformable - Oct 18, 2024

Might relate to issue [Link Removed] In Progress - "The Remove-On-Break feature, set on Fracture Mode on Geometry Collectio ...

Crash caused by a race condition in Nanite::DispatchBasePass()

UE - Rendering - Features - Nanite - Feb 25, 2026

Nanite::BuildShadingCommands() launches two asynchronous tasks: ShadingCommands.SetupTask ShadingCommands.BuildCommandsTask BuildCommandsTask is responsible for modifying ShadingCommands.Commands ...

Crash when a floor mesh is removed while a Vehicle has SimulatePhysics disabled

UE - Runtime - Character - Sep 1, 2026

When SimulatePhysics is disabled, the constraint update is skipped, so a reference to an invalid (already-removed) particle is left behind. As a workaround, the approach suggested by the licensee — ...

Translucent deferred decal materials look different when setting specular attribute directly or via constant node

UE - Rendering - Architecture - Materials - Nov 28, 2025

Translucent deferred decal materials look different when setting their specular material attribute directly on the material node versus setting it via a constant node ...