Map with foliage takes a LONG time to build (not even a lot of foliage)

When building the lighting for Unreal 4, the lighting takes a LONG time to build. I am using production quality lighting, which i know will take longer than lets say… the other settings, but I do not even have much foliage, just some grass (not even a lot… like a small patch) and the second i remove the grass, it builds VERY fast. I have tried to use a “lightmass importance volume” box, but that does absolutely nothing. (i have used multiple tutorials for how to use one) and once again, lighting could take up to an hour+ with this. Please, any help or tutorial links would be VERY useful. Thank you! My specs are listed below:

  1. CPU: i7 4770k
  2. GPU: AMD r9 390 MSI gaming edition (8gb)
  3. RAM: 16GB DDr3 1600mhz.


Make sure your LightSource is set to Stationary and your foliage actors to Movable!

Test it and let us know pls!
Good luck

Thank you for your reply! My lightsource is set to stationary but my foliage was not, so i changed it… on some of them. My issue now is that i had painted the foliage in, and it is not letting me change it. How would i go about fixing this? Thanks!

Hi, you can change the foliage individual actor using the Select option in the foliage tool, see the picture:

Good luck!

Thanks a lot! Really appreciate it. Now, i had tried to make a huge forest type scene but even still, it took a long time. Would doing this make a huge difference for that too or is this simply for smaller builds? (i see you have a lot going on, but i had somewhere between 8000 and 9000 foliage models. Not even close to being the most ever put down but nevertheless still quite a lot)


EDIT: i went ahead and tried to do so, but no luck… it just gives me nothing. (as shown below)

changing all foliages to movable will make the light build be always much faster than static lights.

To change anything about the foliages you can do it in the Mesh editor of that actor. And to change the foliage to movable just click on the foliages in the foliage tool and scroll down to find it at the end, so you can change each one:

Thank you! (literally took 2 minutes now, compared to the 30+ minutes before) I learned a lot actually, throughout this. I do, however, have another question for you (unrelated forgive me, but as you are already willing to help me… i have another question.)

I want to find relatively good assets for Ur4, but there is ONE major issue with that. All too expensive. (cmon, $140 foliage packs?) do you know of any place where i can find good models with actual materials and textures? because so far any free place either advertises for UR4 but then the download only contains stuff for unity or 3dsmax, or has no material at all what so ever. So, if you do have any sites that give free UR4 assets, please give me some links… It would be greatly appreciated. Thank you


No problem! hehe.

Here is a link from our forum, with a massive amount of links with a lot of good things for you. Check it out and be happy, lol:

Also, if this question is answered please mark as solved! Thanks. Good luck!

Thank you very much! One last question, however. When i make a huge geometry… is there a way i can make it so when i make the geometry big, it does not take hours for the lighting to build? Thanks!

The geometry are statics, static lights takes a lot time to build, indeed, but, you can go inside that mesh and decrease the “lightmass resolution”

If won´t be static shadows on top of those static big objects just decrease the lightmass resolution that it will be faster to build.

Also, if the landscape is huge will take a lot of time for sure…

For more specific information about anything, just create another question, so more ppl can see and help you (more ppl, more info, more info the best, lol)

Good luck!

Thanks! c:

no problem! Ask anything! Please mark as resolved, thanks and good studies