Unreal Engine Issues
Unreal Engine Issues
Property Access nodes fail to display variable data in SM transition tooltips
UE - Runtime - Anim BP - May 22, 2026The data shown in the transition tooltip is generated via SKismetLinearExpression::MakeNodeWidget. The issue is that while UK2Node_VariableGet have specific functionality to display the variables a ...
Non-determinism in StaticMeshComponent::BodyInstance when cooking LevelInstances
UE - Runtime - Simulation - May 21, 2026A licensee reported that serialization of LevelSequence with StaticMeshActor with default collision for which mesh has NoCollision profile is not deterministic. The issue seems to be in the fact tha ...
Non-determinism when cooking a UProceduralMeshComponent
UE - Framework - Components - May 21, 2026We received a report from a licensee that UProceduralMeshComponent cook is not deterministic. This is related to the ProcMeshBodySetup member and the fact the UProceduralMeshComponent code changes t ...
check(bRenderStateCreated) fires in SendRenderDynamicData_Concurrent called from FRegisterComponentContext::Process
UE - Rendering - Architecture - RHI - May 18, 2026FRegisterComponentContext::Process() in ActorComponent.cpp iterates over SendRenderDynamicDataPrimitives and calls SendRenderDynamicData_Concurrent() on each. The existing guard checks ::IsValid(Pri ...
Meshes with scaled root bones pop when entering simulation
UE - Runtime - Simulation - May 15, 2026This issue is fallout from the changes in 33851494. Prior to that, we didn’t get the pop on beginning the sim. The problem appears to be that in USkeletalMeshComponent::PerformBlendPhysicsBones we ...
Wrong WPO motion vectors due to Periodic World Space node
UE - Rendering - Graphics Features - May 13, 2026We've noticed smearing in grass due to wrong motion vectors. This appears to be caused by lack of previous frame support in the periodic world space node. This is how we fixed it: In MaterialTempl ...
Chaos FieldSystem examples in the engine content add field nodes every Tick, which creates too many components
UE - Runtime - Character - May 5, 2026Can we add the field on construction instead of on Tick to avoid the performance overhead caused by creating too many components? ...
Curve Atlas Row Parameter uses derivative ops when Texture Sample connected to curveTime input
UE - Rendering - Architecture - Materials - May 1, 2026When a Curve Atlas Row Parameter node is used with a Texture Sampler connected to the curve time input, the sample type uses derivative ops. This has negative performance implications for Nanite co ...
Open Formats: Interchange Import Runtime - Interchange ImportAssetAsync runtime GLB import — materials, textures, tangents, and shaders non-functional in packaged builds (6 issues, UE 5.7.4)
UE - Editor - Open File Formats - Apr 30, 2026Description* We are using Interchange's `UInterchangeManager::ImportAssetAsync()` to import GLB files at runtime in a packaged (Shipping) application. The orchestration layer (`ImportInternal` in `In ...
GetStaticComponentMaskParameterValue returns the value for Static Switch Parameter
UE - Rendering - Architecture - Materials - Apr 24, 2026UMaterialInterface::GetStaticComponentMaskParameterValue gets the parameter value from the static switch list instead of from the StaticComponentMask list GitHub branch 5.8 still looks to have this ...