I’m currently working on a very large-scale world in UE5, and for performance reasons I decided to use a traditional baked lighting workflow instead of Lumen.
For this project, being able to bake lighting for only a small area independently is absolutely essential. Otherwise, changing a single light or small indoor area would require rebuilding lighting for the entire world, which is not practical for a huge open-world project.
I’ve already tried many suggested solutions, including:
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Data Layers
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Levels / Sublevels
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World Partition loading/unloading
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Different baking workflows
I also asked several AI tools for help and experimented with many setups, but none of them truly achieved isolated light baking. In my tests, lighting from different areas still affects each other during CPU Lightmass baking.
At this point I’m honestly not sure whether:
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I’m using the systems incorrectly,
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UE5 simply does not properly support localized CPU Lightmass baking with World Partition,
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or there is some workflow I’m still missing.
I’ve spent a long time researching this issue and couldn’t find a clear solution, so I’m hoping experienced UE5 developers can help clarify the correct workflow.
My goal is something like:
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Bake lighting for one building/floor/interior only
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Rebuild only that area when changes are made
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Avoid rebaking the entire city/world every time
Is this actually possible in UE5 with CPU Lightmass + World Partition?
Or is GPU Lightmass / another workflow currently the only realistic solution?
Any advice or real production workflow examples would be greatly appreciated.