I had a previous issue with lighting and now a new one has appeared. After building the project or lights, my meshes will have black artifacts that appear all over them. It is a little dark in the screenshots because i am not completely done with lighting but what I am testing out returns with this unpleasant look. What could be the reason?
i am using BSP’s that I adjusted and then turned into meshes. I also am using materials and textures from UE4.
Hi!
I’ve seen these kind of artifacts when:
Thank you for the response. I am new to lighting so I will have to look into compressed lightmaps and lightmass portals. I do have a lightmass importance volume and also the static mesh editor shows 2 UV channels for each of my meshes.
No worries hope it will work! 
Under world settings there will be a section called lightmass. If you scroll down the last setting will be compress lightmaps: uncheck it!
Lightmass portals should be placed in your openings where light is coming from (windows/doors)…
I don’t know about your lighting… what lights you use what are your settings in the world lightmass settings…
I am not too sure on exactly what kind of lights I will use throughout the project. Right now I am testing out point lights and spotlights to see what they will look like in the level. I did uncheck the compress lightmaps and nothing changed.
Here is a screenshot of my settings. Also one of how i am planning out the rooms lighting. Not sure if this is too many ceiling lights. they are small lights. I wanted to then use spot lights to fill the room and maybe a few extra point lights to fill the dark spots if there are any.
Lots of lights! 
Are they set as static?
Do you have skylight and directional light in your scene?
Is your building one mesh or have separate walls? What resolution lightmap you set?
Haha, I thought it might be too many. I have thought about reducing the number. They are stationary. I believe that is the default setting they came in as. Yes I do have a skylight and directional light. I added those based on an Unreal Tutorial I found. Just like a lot of this lighting is added based on tutorials lol. Its just a mixture until i figure out what is best. Here is a rough draft look at my level. all walls and windows are their own static meshes, generally 20x400x500. Some might be a little shorter or taller but not by much.
Hi!
If you need that many lights you’ll keep them!
Could you show me one modular piece’s lightmap? …what resolution lightmap you use per wall piece?
All meshes are using 256. I had it set to 512, but for some reason the engine would freeze during a build, when encoding texture got to 43%. So I lowered it. Also I am not sure how to find the lightmap for each mesh but I did find this under the lightmass asettings.
Yeah those are your lightmaps…
If you click on one of your wall pieces then on the detail panel scroll down to Lighting. Is there a checkmark in Overridden Lightmap Res or it’s still set to the default 64?
It is not checked and it shows a value of 256 (grayed out). Also the two settings I highlighted in the picture were changed by me after reading some comments when I had a previous issue. That issue is now resolved but could one of those changes caused my current issue?
Could you stay on this window please and click up on UV and select 1 (not 0) and take a screenshot please? 
It will show the lightmap uv that unreal will use (lightmap coordinate index). I still think it’s a lightmap uv issue…
256 should be enough for a single wall piece!!
I don’t know how unreal generates lightmaps for bps turned to mesh…
It looks ok with a low padding but that shouldn’t cause this kind of artifacts…
I just finished work I’ll think of other possibilities on the way home!
…could you upload your scene somewhere maybe? …
Thank you for all your help! I will see if I can put it in my dropbox and add the link here.
Here is a link to the level. I have to step away from my computer for a bit. i will try and check back on this post asap.
I didn’t get the notification with the link! :S
I’ll have time later this evening and I will check your scene!!
Ok thank you! I have still tried to figure it out, but have not found a solution. One thing that I did try was I added a random wall into my scene. This wall came from the starter content in UE4. I then added a material from the same starter content to that wall. After building the project, the issue still appeared on that new wall. So that is making me think that it has something to do with the world settings or light setting maybe.
I have not tried to turn off all the point light, but I will try it. I did try and build using a different quality. I have been using preview, but did try production. Unfortunately, it did not fix the issue.
Great!! …well …I had the same idea (place a new mesh into the scene to find out if it’s the lighting or the meshes) just didn’t want to ask you since you’ve uploaded your scene!
Hopefully I’ll finish soon and then I’ll check your scene!
…have you tried to turn off all your point lights and leave just the main directional light and your skylight and build like that? :S
What quality you build your light? /Preview, Medium…/
…ok soon I will see it!
Sometimes preview gives strange results… but medium should look ok…
Hopefully I’ll be more clever after seeing your scene!
