Summary
When building HLODs for a partial selection of actors within a World Partition cell, the resulting merged HLOD proxy displays black stained/corrupted material across portions of the mesh, even though the source actors render correctly at full detail.
What I’ve ruled out:
Confirmed one source mesh had an emissive material; changed it to a plain non-emissive material (asphalt) — issue persisted
Checked Project Settings for Virtual Texture options — not exposed/available in UEFN’s interface
Confirmed affected source meshes have Nanite enabled (not the non-Nanite HLOD bug)
Please select what you are reporting on:
Unreal Editor for Fortnite
What Type of Bug are you experiencing?
Assets
Steps to Reproduce
Large World Partition map (~18.83 x 16.02 x 4.64 km), Cell Size 12,800, Loading Range 25,600
Select a subset of static mesh actors (rock/terrain formation) within one World Partition cell
Build → Build HLODs (Selected Actors)
Resulting HLOD proxy shows black stains across the merged mesh surface
Expected Result
Clean merged HLOD proxy matching source mesh materials at a distance
Observed Result
Black stained/corrupted material on portions of the merged proxy
Platform(s)
windows
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Additional Notes
Additional context: “Build HLODs (Selected Actors)” appears to process the entire World Partition cell containing the selection, not just the selected actors — worth confirming if this is intended behavior.