Light map building error


I’m really new to unreal engine and I have a problem. When I’m trying buliding the light map for my scene I get an error and the building stops. So far I couldn’t identify the problem. Id someone knows what is the problem and how to fix it I would appreciate the help. I’m linked a picture with the error text.

Thanks for the hellp and happy holidays.

Hi LordBaluka,

As the error suggests you have run out of memory while building your scene.

Have a look at a Troubleshooting and Tips guide I put together for Lightmass/Swarm Agent a while back: A new, community-hosted Unreal Engine Wiki - Announcements - Unreal Engine Forums

This will have some tips for reducing the lightmap resolutions of your foliage, or disabling foliage lightmaps all together. It will also detail some other things that can help improve your light build times and solve your issue.

  • The biggest thing here would be to make sure you have a lightmass importance volume around your playable areas, You can use more than one.
  • Decrease the lightmap resolution in the foliage tool for all your foliage meshes. Use either 8 or 4 for the resolution.
  • Reduce the number of foliage instances, as these can add up quickly for lightmass calculations and texture pool.
  • Disable Lightmaps on meshes that may not need them, like grass or flowers or anything that needs to move dynamically, since precomputed lighting would never be accurate in this case.
  • If you’re still getting the lightmass crash with “Ran out of Memory” error you may want to add additional RAM to your PC as light builds and the calculations needed to create the textures can be intensive depending on your the number of meshes, size of the map, and lightmap resolutions.

I hope this helps.


Thank you for your help I’m going to try these methods as soon as I can. :slight_smile: