Unreal Engine Issues
Unreal Engine Issues
GPU Scene reserved resources can break Niagara mesh preview rendering
UE - Rendering - Architecture - Niagara - Sep 28, 2026When 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 ...
Particle Random Value is the same for all particles with a Niagara Mesh Renderer
UE - Rendering - Architecture - Niagara - Sep 28, 2026A material using the Particle Random Value node returns the same value for every particle drawn by a Niagara Mesh Renderer. Particle transforms are not affected, only the random value. This happens ...
[Niagara][5.8] Data Channel Read and Write register with an identical type hash when fx.Niagara.DataChannels.Enabled is set from ini, hitting checkf in FNiagaraTypeRegistry::RegisterTypeInternal
UE - Rendering - Architecture - Niagara - Sep 28, 2026Affects: 5.8 (verified on Release-5.8), Windows, EditorSummary Adding fx.Niagara.DataChannels.Enabled=true to an ini file makes the Niagara editor assert when a Data Channel Read is created. The sa ...
Race condition in GetFunctionSig_Write() and other function signatures
UE - Rendering - Architecture - Niagara - Sep 11, 2026A race condition exists in GetFunctionSig_Write() and other places where FNiagaraFunctionSignature is lazily initialized because multiple worker threads can progress past if (!Sig.IsValid()) and st ...
MRQ render with a slow output format drives Niagara GPU tick flush into its dummy-view path, causing an access violation in SetShaderParameters
UE - Rendering - Architecture - Niagara - Aug 18, 2026Sorry for the AI ticket, but it did a better job than I could: Rendering a level sequence through Movie Render Queue crashes the editor with an EXCEPTION_ACCESS_VIOLATION when the scene contains a N ...
Values passed through VertexInterpolators are incorrect in the pixel shader on Niagara mesh particles when material uses SubUV animation
UE - Rendering - Architecture - Niagara - Jul 29, 2026Passing through the vertex interpolator, the DebugFloat3Values output appears garbled, but if you remove the VertexInterpolator the particle’s position is accurately returned. This happens with Part ...
Niagara NDC GPU Instance Counter leak
UE - Rendering - Architecture - Niagara - Jun 5, 2026In NiagaraDataChannelData.cpp, FNiagaraDataChannelDataProxy::EndFrame enqueues a GPU readback for each entry in PendingGPUReadbackBuffers, but the corresponding FNiagaraGPUInstanceCountManager::Free ...
Crash in FNiagaraEditorModule::PrecompileDuplicate() — null deref of Handle.GetEmitterData() in third "finish off the emitters" loop
UE - Rendering - Architecture - Niagara - Apr 30, 2026Crash / null pointer dereference in FNiagaraEditorModule::PrecompileDuplicate(). File: Engine/Plugins/FX/Niagara/Source/NiagaraEditor/Private/NiagaraCompiler.cpp Function: FNiagaraEditorModule::Pre ...
Wrong calculation of "MaxAllocatedCountEstimate" inside FNiagaraRendererRibbons::GenerateDynamicData()
UE - Rendering - Architecture - Niagara - Mar 20, 2026Starting with UE 5.4, function FNiagaraRendererRibbons::GenerateDynamicData() from file [NiagaraRendererRibbons.cpp] attempts to calculate DynamicData->MaxAllocatedCountEstimate as such: DynamicDat ...
NDC Sorting Incorrect
UE - Rendering - Architecture - Niagara - Mar 12, 2026Using the new NDC BP nodes in 5.7 causes sorting to break; one system, regardless of world placement, is always drawn over the other. Even when the viewpoint puts the dominant system in the foregrou ...