Lightbuild ran out of memory, have plenty of memory left

Hey there,

I’ve posted this issue before, but that fix didn’t help. I’ve had this issue since the first time using unreal engine. I add a lot of static meshes and i can build light, if i add a tiny bit of foliage, some grass or trees and i run out of memory. This happened across 4 different projects in 4.6, 4.7 and 4.8 so it’s not project problem.

I always get an error similar to this:

Does anybody know the issue?
Right now the scene looks like this, which is rather small and it has a lightmass important volume.

My specs:
Intel i7 3770K 3.8Ghz
MSI Z77A-G45
16Gb DDR3 Corsair ram
Geforce GTX 670 4gb ftw edtion

This should be more than enough to run the builds.

If someone could help that’d be nice as i don’t want full dynamic light.


Suggestion from a friend was to increase virtual memory. Seemed to fix the issue for now.

I have recently made a Swarm Agent/Lightmass troubleshooting guide for the Wiki that should in more simple issues like this. You can have a look here if you’re interested: A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums

Ultimately, using foliage in larger/medium sized levels you will need to make sure that you go into the foliage tool and set the lightmap resolution. The static meshes default resolution will be used otherwise which can cause these kinds of things to happen. Setitng it to 4 or 8 for the LM resolution will be much better since the foliage lightmaps will be batched together into clusters.

There are other tips in this guide that are helpful as well.