Landscape indirect lighting sample density?

Where can I change the indirect lighting sample density for landscapes?

I have a landscape and a water plane Static mesh, the indirect lighting samples on the landscape is more much denser than on the plane, how Lightmass makes the decision or can I control the density for the plane?

Thanks!

Hi PowerDesign,

You can adjust the Indirect Lighting Samples by opening the World Settings panel (Settings > World Settings), then you can navigate down to the Lightmass section and adjust the Volume Light Sample Placement to a lower value. The default value is 1. You can lower it by just a little to get slightly more dense placement or you can take it down to 0.1. You can try any value between 0.1 and 1 to get the density you like, but the more samples placed the more memory will be used.

There is no way to adjust this for a specific asset though. Also make sure that you’re using a Lightmass Importance Volume to get even placement of these samples.

I hope this helps.

Tim

Thanks, Tim, it’s helpful. Do you have any ideas about the other question: water plane on landscape, water plane has the same density (much less dense than landscape surface) as the air, Lightmass makes the decision automatically?

I did some tests on a fresh scene: the default Plane and a terrain with hills and valleys above or below the Plane. My conclusion is the automatic decision of Lightmass is not stable.

Volume Light Sample Placement Scale == 0.5: same density on Plane/hills/valleys, air is sparse, good.

Volume Light Sample Placement Scale == 0.25: air is much more denser, Plane assumes the Scale correctly, terrain is as sparse as air but not as dense as Plane (problem).

=============================================

If you put some small buildings on a terrain, the tops of the buildings don’t have dense samples.

If a building is tall enough, the top of the building will be considered walk-able and gets more samples.

This explains a situation I met before: ThirdPerson template scene (ground and walls forming a playable area), I made a terrain for testing which happens to be at the same height as the ground, then ground (and terrain) get less samples but the wall tops are good.