Lighting huge terrains - Lightmass Importance Volume
I build a game with huge terrain.My terrain is huge as I use real world scale for environment which has a surface of 2x2 km .Now the problem is that when I try to build the level ,especially lightning my PC gets stuck for 20 minutes and at the end I am getting this message:
"No important volume found and the scene is so large that the automatically synthesized volume will not yield good results.Please add a tightly bounding lightmass importance volume to optimize your scene's quality and lightning."
Also,after I added a terrain material with 3 layers my terrain looks like this:
You can see the black gaps which shouldn't be there. My terrain settings:
Section Size: 255x255 quads
Section Per comp: 2x2
Resize mode - resample
What is the correct strategy to handle a huge terrain?
You need to add a "Lightmass Importance Volume" to avoid this error, it can be found in the Volumes tab of the modes toolbar.
Scale it up so it covers all of the important areas of your mesh, you can make it cover the entire landscape, but it is best to only cover the parts that the player will be walking through.
Because it takes a long time to build the lighting for terrains larger than 1x1km I would recommend switching over to using Dynamic Lighting instead of baked lighting, you will not need to rebuild lighting at all this way, but it is slightly more expensive performance wise. For more details on this enabling this see the documentation here but the basic idea is to set your lights to Movable to switch it to dynamic.
To disable pre-baked lighting entirely go into your project settings under the Rendering tab and disable "Allow static Lighting" (you will need to restart the editor to apply the change) and then go into the World Settings panel in the Lightmass section, and enable "Force No Precomputed Lighting". Now build the lighting one last time and it will apply the change.
Hope that helps!
answered Nov 14 '14 at 08:33 PM
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