Lightmass ran out of memory - how to fix it?

Hi there,

I searched the answerhub already and I found a question with the exact same problem but no one answered it: Light mass crashed how to fix it? - Rendering - Epic Developer Community Forums

I also have the fatal Error in Line 193 and Line 1356.

My scene is big and I already could build the lighting but after I added the grass, it just won’t build the lighting…
I have 64gb RAM so I hope I can fix it without adding more…

My Specs are:

  • Intel(R) Xeon(R) CPU E5-2687W0 @ 3.10GHz (16CPUs), ~3.1GHz
  • 64GB RAM
  • 64GB Virtual RAM

Can anybody help me?

Anyone who can help?

How large is your level and what is the lightmap resolution of those grasses? I’m guessing you also have a landscape, have you increased the lightmap res.(Static Lighting Resolution) for it?

Thank you for replying.
Here’s a screenshot of my scene. The LMR of the grass is 16. I can’t go lower otherwise it would look like crap. It already doesn’t look very nice but it’s the lowest I can go.
The static lighting resolution of the landscape is currently set as default 1,0.
would it be a solution to take dynamic lighting instead of static lighting?

and a closer look at one of the gardens with the grass:

thank you!

The map is pretty big and with that foliage it is possible that you are actually running out of RAM. Before switching to dynamic lighting try this; scale the lightmass importance volume down until it covers the buildings only(the area users are supposed to walk around or see from up close) If that works for your computer and purposes then great! If not you may have to use movable directional light and skylight. Dont forget to enable Force NoPrecomputed Lighting in World Settings > Lightmass and then rebuild the lights afterwards(it is going to be a quick build to get rid of any existing lightmap)

If you are planning to make interior walkthrough as well you can get the buildings in separate, smaller levels and build lighting for each of them separately.

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