Unloading a World Partition region during nested Level Instance inline editing prevents exiting editing mode

UE - World Creation - Worldbuilding Tools - Level Instances - Jul 28, 2025

In the case of a single-layer Level Instance, actors are still referenced even when the region is unloaded. However, in the case of nested Level Instances, the level being edited is discarded when t ...

Mutable RemoveMesh node with data from DataTable

UE - Anim - Mutable - Jul 28, 2025

Hi, We are trying to use Mutable plugin to avoid clipping using the RemoveMeshNode with data from DataTables. However we are having trouble with the most basic example of our idea. We have a Data ...

Copy-pasting custom property nodes (ControRig etc.) results in invalid bindings, perf issues

UE - Anim - Rigging - Control Rig - Jul 28, 2025

From this UDN: [Link Removed] Suggested fix:Override PostPasteNode to perform the GUID update andAdd validation on load to strip 'invalid' copies that do not correspond to a valid pin input ...

Restoring AnimInstance fails when ControlRig and Motion tracks are consecutive in sequencer

UE - Anim - Anim in Engine - Jul 27, 2025

In the Sequencer, Control Rig and Animation tracks are placed consecutively. During the transition, the Animation track captures the AnimInstance state before the ControlRig track's RestoreState is ...

Merge Actor - Approximate Actors algorithm is using Mesh Description directly rather than the Nanite parameters

UE - World Creation - Worldbuilding Tools - Merge Actor - Jul 25, 2025

In an ideal world, all mesh merge algorithms should have the option to use as input one of the followingRender mesh (non-nanite) (+ the option to target a specific LOD)Mesh Description (+ the option ...

UWorldPartitionSubsystem::IsStreamingCompleted returning the wrong query result when all cells and actors in location are in DataLayers

UE - World Creation - Worldbuilding Tools - World Partition - Jul 24, 2025

Context: Data Layers is a system within World Partition used to organize Actors both in the Editor and at runtime. It allows for the user to dynamically load and unload layers in the Editor to help ...

ULevelSequence trying to duplicate a REINST_ class when creating new custom binding in ConvertOldSpawnables()

UE - Framework - Blueprint Compiler - Jul 23, 2025

The assert that we're hitting is:Cannot replace existing object of a different class.  New Object: /Engine/Transient.REINST_BPC_NPC_VFX_C_230 /Game/Maps/[REDACTED]/Levels/[REDACTED]/LevelSequence/ ...

Artifacts appear on translucent particle systems during camera motion blur

UE - Rendering Architecture - Jul 23, 2025

Translucent particle systems exhibit visual artifacts when the camera moves, even though motion vectors are disabled for the particle emitters. While switching the Translucency Pass to "After Motio ...

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 ...

Farfield shadow in lumen scene

UE - Graphics Features - Jul 21, 2025

Shadows in the Lumen Scene from Lumen's Direct Lighting do not match the world when in the Lumen Far Field. This leads to shadows where there should not be any, and missing shadows where there shou ...