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To use a different resolution for part of a Landscape actor, use the Landscape tool Manage Mode (Unreal Engine Documentation) to move components into a different level, then change the Enlighten Quality of the Landscape Streaming Proxy actor.

Lightmap resolution

The lightmap pixel size determines the indirect lighting resolution for actors with Contribute Lightmap lighting mode.

If you specify a smaller lightmap pixel size for an actor, Enlighten produces more lightmap pixels for each chart. Each Enlighten Quality preset also determines the lightmap pixel size.

Probe resolution

The probe resolution determines the indirect lighting for actors with Probe or Contribute Probe lighting mode.

To set the maximum resolution of the probe grid for the entire world, change the Adaptive Probe Grid Spacing in the world properties.

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