Unreal Engine Issues
Unreal Engine Issues
SkyLight Leaking does not affect reflections when the SkyLight is static but static lighting is disallowed
UE - Rendering - Graphics Features - Sep 10, 2025Reflections do not receive SkyLight leakage contribution from a static SkyLight when static lighting is disallowed. This is caused by the function UpdateSkyIrradianceGpuBuffer checking if the SkyLig ...
Lumen Translucency lighting vs opaque mismatch is larger than expected
UE - Rendering - Graphics Features - Lumen - Sep 5, 2025The licensee's VFX team has been struggling with getting their Niagara systems with translucent materials to fit into the environments they are being used in. In a project with default settings, the ...
Cook non-determinism when serializing UObject pointers pointing to garbage
UE - Core - Systems - Aug 25, 2025There's a cook determinism issue in the way UObject unversioned serialization handles UObject pointers pointing to garbage. Depending on GC timing, it can either be skipped (as a property matching C ...
Heterogeneous Volume Actor causes ensures to trigger in Debug builds
UE - Niagara - Aug 24, 2025When a heterogeneous volume actor is used with a volume material in a debug build, the following ensures are triggered: Ensure condition failed: UniformBufferValue || EnumHasAnyFlags(AutomaticallyBo ...
Slow editor/PIE loading of UWorldPartitionHLODSourceActorsFromCell
UE - World Creation - Worldbuilding Tools - World Partition - Aug 22, 2025Loading UWorldPartitionHLODSourceActorsFromCell takes a lot of time in editor + PIE when it contains a lot of actors per UWorldPartitionHLODSourceActorsFromCell (between 2K and 2K actors). ...
Missing PSO Precaches in the engine
UE - Rendering - Architecture - RHI - Aug 20, 2025A licensee wanted to report some missing PSO Precaching they found, which they have fixed locally: 1. UCableComponent doesn't implement CollectPSOPrecacheData or call CheckPSOPrecachingAndBoostPri ...
Sub-world partitions do not properly handle partial editor loading as world partition standalone level instances' spatially loaded actors do not get loaded even when the Level Instance is force loaded or loaded in by region.
UE - World Creation - Worldbuilding Tools - World Partition - Aug 19, 2025Context Level Instancing is a level-based workflow designed to improve and streamline the level editing experience. In a standalone Level Behavior, when the Level Instance Actor is loaded through it ...
bIncludeComponentLocationIntoBounds breaks bounds calculations
UE - Runtime - Animation - Aug 13, 2025Bounds generation when bIncludeComponentLocationIntoBounds is active is broken. Both the calculation of the local bounds and the world bounds are incorrect (see screenshot). When that flag is acti ...
Lumen Card Sharing is active on material with custom primitive data
UE - Rendering - Graphics Features - Lumen - Aug 13, 2025The wrong emissive value may be used on Nanite objects with custom primitive data when Lumen card sharing is enabled. This issue can be mitigated with: r.LumenScene.SurfaceCache.AllowCardSharing 0 ...
AnimToTexture vertex animation stutters on looping frame
UE - Characters - Animation - Aug 8, 2025The AnimToTexture plugin generates an animated texture that results in a stutter when the animation loops. This looks to be related to the code in UAnimToTextureBPLibrary::AnimationToTexture which ...