World Partition masterplan: how to build HLODs incrementally without loading whole world (RAM limit)?

Hi everyone, I’m working on a large architectural masterplan (an entire island) in World Partition with many areas/buildings.

Archviz masterplan: lots of meshes / buildings / landscape, imported area by area. If I keep everything active/loaded, I eventually run out of RAM/VRAM in the editor. (I know I can Load/unload WP cells and Use Data Layers to enable/disable groups of actors.)

The HLOD problem I’m unsure about

I need a final HLOD setup for the whole island (so far-distance views and flythroughs work smoothly). But I can’t realistically load the whole world at once in the editor to build the HLOD.

My questions

  1. Do I need the entire world loaded to build “final” HLODs for the whole island, or can HLODs be generated per-region/cell, without wiping out previously generated HLODs?

  2. If I FISRT load Area A cells → build HLODs, THEN unload Area A → load Area B → build HLODs
    Will the HLODs for Area A remain, or can the next build overwrite/delete them because Area A is unloaded?

  3. What’s the correct workflow to incrementally build up HLODs for a huge WP world without running out of memory?

  4. Is there a recommended approach (editor UI vs commandlet/build farm) for large projects like this?

UE version: **5.7 / GCard: rtx 3090 24 gb vram
**
Any guidance on the intended pipeline here would be hugely appreciated, as I could figure out these issues from the manual.

Thanks!