Anyone else has such ridiculous render times? I’m now a bit afraid to edit the game, because it could crash and everything would be lost. I use Koola’s ini settings i found somewhere here in the forum … maybe not so good idea 
It depends on your level, meshes, light setup,… 
When you want to avoid long light builds, you will have to use dynamic light
In version 4.7.2 i had render times of a few hours. I’m unaware of any drastic changes i did to the settings. It might have to do with the ini settings i added, but i thought they were okay when i initially used them. And now every render takes forever.
Did you check what the different settings in the ini file does? And what does it change vs. the defaults?
This is the current setting i use to render with high quality
I think this is even default?
Meanwhile, BUILDING LIGHTING 82%!
Out of curiosity… does UE4 Editor run at 100% of cpu?
1-2%
/10chars
Swarm/UE4/Something should be maxing out your cpu when it’s building.
I haven’t tried those ini settings but I’d be very surprised if they didn’t add to your build times (significantly).
Also perhaps the build quality setting changed (production vs preview or whatever the others are, I haven’t used Lightmass in ages).
Any idea how i can increase CPU usage? When i initial started the build i went afk, then my computer went into power safe mode. This might have led to the cpu usage drop, and hasn’t recovered since, beside power safe mode has been toggeled now several times.
I don’t even know what power safe mode is =
A day or two for a big/high quality lighting build wouldn’t surprise me, but it should definitely be using all/most of any CPU power available.
On the upside it should be just about finished right?
Save often.
I would turn it off and on again. It clearly isn’t doing anything now. Hopefully you will have your work auto-saved by the program.
If it isn’t, well, we’ve all been there, and all learned that lesson. 
What version of UE4 are you using? Our build machine is a Mac (iOS game) and from 4.1 through 4.6, our build times were atrocious: 5-6 hours on a maxed out garbage can Mac Pro and it never used more than one logical core. Since 4.7, things have been much better and it uses a lot more of the computing power available to it. We can do a clean device build from scratch in less than an hour and an incremental build often in 10 minutes or less.
I’m not sure if that was a Mac specific problem or which platform you’re on, but if you’re not on 4.7, you might want to upgrade your project. 4.7 added a lot of async stuff and has been a really solid performant version for us.
Thanks, well I’m on Windows, and use latest build. At least this build mentioned above, is done now
I am using the latest build and have a 16 core (32 hyperthreaded cores) system with 128 Gb ECC Memory and it seems to go from as low as 1 core used to all 32,(I use process lasso pro to core usage) also seems that Swarm connecting creates lag.
Any tweek suggestions you have found help out would be appreciated, as lighting still takes forever (using 2 x 970 in SLI mode with dedicated 2nd core for rendering)
Greetings. I am not that experienced with UE4, I have only used cryengine sdk, unity and a few 2d engines.
I have the same problem with long “build light” times but since my level is not that big, my “build light” time is around 10 hours. Is this normal for an i7@2.80 CPU, 6 GB RAM and a geforce GTX 470?
I use the 4.7.6 version, the build light quality is set to medium and the only lights that I use in my level are 7 static spot lights and the default directional light. This is the first time that I tried to build light for my level.
Also I have imported in my level, an urban scenery from 3DS but with no textures. This scenery is a little bit complex, around 1000 separate meshes in 3DS . So the final number of static mesh actors in my level is around 5200, but most of them (except the urban scenery meshes) are just basic simple geometry like spheres and cubes that I have placed them in the level with the help of a grid blueprint. I also know that I have many overlapping geometries but it will take hours to fix them now.
So I would like to ask the community…how is it possible to develop a level when you have to wait for 10 hours every time that you change the light and have to build it again?
Am I doing something wrong? What’s the normal build light time for a simple level?
The reason it’s taking so long is that you have a large number of objects, and probably a high poly count. You will also get poor real-time performance with that many objects, which is a waste if they are low poly meshes, so it would be better to attach some of them together in 3ds before exporting to UE4.
10 hours isn’t bad, for big complete maps it can take a lot longer. Remember you’re doing more work than like you would rendering a still image in 3ds , it has to render the whole level.
Will UE4 see GPU rendering?
Ok thanks for your answer. I don’t think that the poly count is high (by the way, what is a “high” poly count number in a UE4 level?), as i said the vast majority of separate meshes are just cubes and simple basic geometry. The game plays well in real time after I build it.
I have already imported from 3ds the major parts of the urban scenery as groups. Also I have made groups of many meshes in the level. Does this help to reduce the building light time?
And a final question. If I build the light in the same level, will it take again 10 hours to build it again? Does it have to compute the light again from scratch?
I have an interior level with about 6000 static meshes and at least 50 lights in it. Takes 3 or 4 hours to bake on maximum quality in 4.9. That is significant improvement from unity3d, where the similar levels could take 9 hours or more - with default settings. However, I have more ram and geometry is very simple (low poly).
I think your system might be running out of memory and hitting swap file. When that happens computation will slow to crawl. Check if system is hitting swap file (by using task manager or just by looking at your HDD led while lighting is calculated).
Ok thanks mate.