lighting wont' build

I have terrain with default sand/rock texture ( in engine), no objects on terrain and one is hidden , and while it does prepare lighting for building just fine, when it starts to build, it stays at 0% even after an hour.

Is that normal for a 4097x4097 terrain with 2 m/pixel and if so , how long should this take ?

I’ve had large terrains before, and it was always able to build, and I even cleared cache, rebuilt and removed everything in DIR as suggested on thread.

Using 4.13 and yes I have a lightmass volume.


Alright, through some testing I did, given I finally had some spare time, seems to indicate unless I’ve missed something that light building anything but the most modest of worlds takes a coons age, unless you have the most ram, fastest processor & /or a giant megacomputer from space

I updated my GPU so I"m far above the recommended now, but my ram is still stuck at 8gb, maybe that’s some of this I don’t know, and ya my quad core amd 3.2ghz 4 cores is far from current/fast, but I get by easily enough.

What IS the recommended hardware combo to be able to build a 255 component 2 sections 10 component 5101 sq terrain , fairly complex design with two lights and sun flare setup and have it not take all day ?

Thx anyone for input on what we’d need LOL


i am currently rendering a lighting scene as well (writing this on other pc) but i discovered that size doesnt Always matter. it is more what you have done on that square of terrain. if you have a completely empty level you dont need a good pc. but if you got it full with large foilage like trees in a dense forest it will need quite a lot. and then it is not your CPU but mainly your RAM available. you should have a decent CPU still but you dont need the best of the best. around 24 to 64 GB of RAM will be enough for near all scenes (the actual time still needs to be decent to let it do the job fast) i mean i have a crappy CPU and 16 GB of RAM, it works but not very fast. i would reccomend something like an i7/xeon. with at least 4 cores and 8 threads. the i7 extreme edition would be very good at it if you got the money to spend. with that i would take at least 32 GB of ram to have enough. furthermore GPU is not really involved in the lighting build. but will still be used in other aspects of creating a level. such as taking high res screenshots. but only upgrading your GPU for lighting builds wont really help you at all…

32GB ECC RAM, 8core AMD, GTX1080 // Landscape = 8k
takes me about 10 hours of “0%”, i have seen it take up to 21 hours for my build …

GameKing is correct …
Im running about 30 million trees currently … countless grass, i cant even begin to imagine the grass count …

Thanks everyone so much for your input,very much appreciated as I’ve never had a rig with more than 8gb of ram, not yet anyway, that’s coming.

Yes, I always knew that with complexity is likely to bring hardcore light build times,I just wasn’t sure exactly how long it would ultimately take ,eek gad.

Angry@ 30 mill trees, is that a huge worldmachine world or something ? :wink:

I wondered yes, about what kind of rig was required, given the ‘build’ isn’t done on my machine but by swarm, not that I’m entirely sure HOW that even works .

Angry@ can you give me an idea of exactly how big your scene (s) are and if you are considering a upgrade to alleviate such huge build times ? also you say its taken up to 21 hrs of 0%, so how long do your huge build take in the end then ? YOu clearly have some kind of forest sim there :wink: I’m also curious given that huge load you have there, does that slow down the editor sufficient that its slowing your progress as mine currently Is ( though NOT compared to mine, I have nothing yet anywhere near that level )

THx again all appreciated, at least I know its not something non clever I’ve done o_0

How am I supposed to manage my scene if lighting takes this long ? ( can’t)

What kind of system would I need to build in minutes, vs hours ?

Is anyone building lighting, and not having it take ‘hours’ ?

Be curious to know what kind of system they have.