Hello Epic Games Support!
We have noticed that we have GPU validation crashes on unaligned memory reads and MMU fault when accessing memory in Nanite compute shaders. Bug is not related to single GPU model or driver version. It happens with different frequency for different PCs but there is nothing specific to their configuration.
Unaligned address crash for one of the shaders in BasePass shown below. The only value that can hold unaligned value is PositionOffset, which means that Cluster data is invalid.
My question is regarding to the changes in FPackedCluster data structure which we integrated with engine version upgrade to UE5.5 Engine/Source/Runtime/Engine/Public/Rendering/NaniteResources.h
Does this change require all Nanite meshes to be manually re-imported in order to generate updated FPackedCluster / NaniteResourcesPtr.Get().StreamablePages data?
I didn’t found version tracking in FPackedCluster and from my observation NaniteResourcesPtr.Get().StreamablePages updates called only on mesh import. If assets data is handled automatically with version upgrade I will be glad to learn it and if not I would like to get a confirmation from Epic team before doing re-import of all Nanite assets in a big project.
Thank you,
Oleksii
https://github.com/EpicGames/UnrealEngine/commit/44f9aec3a74110380ad66f06c9cf402b4af32acb