Unreal Engine Issues

Possible shader preload deadlock when using Zen streaming

The deadlock happens when enough shader preload are launch in parallel on a slower IO backend (like zen). When that happens, the preload starts a waiting period that never ends because it cannot be ...

World Bookmark can't be saved when a Private Data Layer is "collected" by the UDataLayerEditorState

The World Bookmark system cannot properly handle Private Data Layer. The current state can make them unusable since the Bookmark might not be saveable. ...

Niagara NDC GPU Instance Counter leak

In NiagaraDataChannelData.cpp, FNiagaraDataChannelDataProxy::EndFrame enqueues a GPU readback for each entry in PendingGPUReadbackBuffers, but the corresponding FNiagaraGPUInstanceCountManager::Free ...

Water plugin's RVT/ISR shader permutations fail PSO creation with instanced stereo (D3D12 SM6)

With Instanced Stereo Rendering enabled and the Water plugin enabled (default), PSO precaching speculatively compiles WorldGridMaterial × FWaterVertexFactory* permutations for the Runtime Virtual Te ...

Assert crash when playing Groom Cache with Card Mesh LOD

Playing a Guides Groom Cache while Card Mesh LOD (Guide-Based) is active causes an assert in RunHairStrandsInterpolation_Cards when the renderer switches to Card LOD. Assert location:Plugins/Runtim ...

Niagara Mesh Renderer registers NumParticles x NumMeshVariants TLAS instances

When using the Niagara Mesh Renderer with multiple mesh variants selected via MeshIndex, the number of TLAS instances allocated is NumParticles × NumMeshVariants and enabling the Path Tracer can ca ...

PrepareTextureResources is being called repeatedly (on commandlets and potentially other cases)

Implement a commandlet that renders (with `-AllowCommandletRendering`) and frequently calls `CommandletHelpers::TickEngine()`.Have the commandlet load a map containing a world-partitioned landscape. T ...

Blocky artifacts in right eye when reflection captures are used

VSM + Nanite Tessellation + Volumetric Fog Shadow leaking while the Directional lighting is rotating

Functions referenced via a Property Access node don't appear in blueprint Find By Class Member results

Finding Reference By Class Member fails to find references to bp functions from property access nodes. ...