Light build creates dark or black spots on geometry thats too close i assume.

Light build creates dark or black spots on geometry thats too close i assume. I am wondering how i can fix this. See the screenshot… 1 screenshot shows a plant flat geometry next to a wall… the other is showing some roof tiles that sometimes get darkened… only answer i can come up with is geometry beign too close… Thid screenshot shows a wall that is darkened because it has objects on the other side of it.

That means your lightmap UV’s need to be better or you might need to increase the lightmap resolution.

Here you can see how to create a perfect lightmap: :slight_smile:

Sorry the uvs arent causing this. I mean they may be a factor in the japanese roof tiling in the 1 screenshot, but hte rest of it … no way… See the attached screenshots. This issue even happens on small stones and plants on terrain. If things are too close to other geometry… they get blackened. Like the vine plant on the wall is a prime example. When lighting is built it turns completely black… yet there is nothing blocking it to do this.

If the UVs are really not the culprit here (although the japanese roof UVs look as if my cat played with them :slight_smile: ), then it could be something in your material that pevents bounce light from being catched…
Could you please show us your material setup.
Do you use normal maps? Sometimes they can be the cause of this as well…

Ran across a similar problem when making map object in 3ds Max.

The issue turns out if you use the “relative” scaling tool to scale down the object it does not change the “local” scale and the object maintains the original value. Lets say you make a paperclip the size of a building and then scale it down to it’s proper world scale when lightmaped in UE4 it seems to do so using the local scale value. To fix it I just had to do an “xform reset”

Yea that was unreal auto generate uv on that roof uv thing… but im more concerned with why its happening everywhere else including foliage on landscape. Ill randomly get black rocks. And the materials are all pretty barebones… That wall for instance is a color texture, a roughness, a metallic, ao, and normal map… nothing else… Nothing special is going on here.

The transforms are frozen… not something i would miss, and even if it was… this happens on mostly everything if its too close its like a wall being too thin so it takes stuff from the other side… or like that plant too close to the wall so it turns black and takes shadow… point is both sides shouldnt get that shadow… only the side facing the other object.

so yea… definently not a scale thing. Its a scene wide issue. In all my time using unreal engine 4 i have always experienced this issue… test it yourself and i bet you … you will get it too. Thin wall next to another peice of geometry. or layering a decal that is geometry instead of the unreal decal on a wall… or right next to it…

To me this seems a problem in the way lightmaps are rendered but i dont know if there is a setting to fix that.

The issue is your UV’s, the automatic flatten UV’s tool is not a good way to create lightmap UV’s, you can see in your results that it splits up way too much and you have a lot of really tiny parts there, that will mean that to get good results you’ll have to have really really high resolution lightmaps, which I think even at 2k resolution wouldn’t be enough. On the walls, the lightmap resolution is too low, and you could do better UV’s there also.

Now for the vegetation, the UV’s are fine, but you should probably do that as a decal rather than placing a mesh there.

No its not. Uv could be an issue on the gate, but the wall with windows has perfect uvs. I am pretty sure i know the cause now , but i still have no idea how to fix it. You see my scene is lit with a skylight only like a cloudy day… no directional light or anything. When its lit with indirect lighting only these issues appear all over. This is my guess on what is causing hte problem… I dont think the problem appears with direct lighting like a point, spot, or directional light. I think lightmass just sucks with indirect lighting from just a skylight or light bounce. So the question is what setting might i use to fix that?

As I initially wrote, maybe your materials are preventing bounce light from being caught…
What happens if you increase the indirect lighting boost level?

I think you have a problem with object normals. Stair steps look like their ends have smooth shading on them (smooth shading == multiple faces sharing same smoothing group), and japanese tiled roof looks like every tile has random normal directions.

So, either incorrectly calculated normals, or incorrectly canculated tangents, or incorrectly computed normalmap.

The effect on the stairs is very similar to what you get when make a box out of 8 faces, put every face in single smoothing group and then light it up with per-pixel lighting.

Actually i wasnt even looking at the stairs as a problem. I didnt notice that myself. I really can care less about something so tiny… but no the stares are fine… those are flat… with hard edge normals… Nothing special going on there. The shadow thing could be needing more res, but again im not even looking at that as a problem. Lets alll just focus on the wall with the window and the plant. Perfect UVs… hardedge model… just a wood texture and a normal texture from a 2d image for tiny bumps in the wood… nothing major… nothing special. That wood has the shadow from the other side on that 1 spot because there is a big plant box on the other end right next to the walls other side. Looks like lightmass sucks with indirect lighting so im trying to find a way to see if there are settings that can help this.

Well the materials are normal materials. Nothing special at all… just the color , normal, roughness, and metallic textures directly plugged in. The model itself for the wall with windows is just hard edge geometry… the normals are just details for the woods texture… so its a little bumpy.

As for the indirect lighting boost level… the skylight intensity is at 25, the indirect lighting intensity is at 12, the color is a .463 grey …

And as for the world settings… here is a screenshot instead of typing that all out…

If you’re talking about massive black spot at the bottom of the wall in the 3rd screen, that also could be related to misaligned normals.

You need to check normals in the engine (honestly, just do it). Open mesh in static mesh editor, enable normal map display (button at the toolbars) and make sure they’re pointing in the correct direction. Check tangents/binormals too. Black plant on the wall can also be caused by incorrect normal direction or flipped normals.

Because, honestly, there’s no reason to think that the model has been correctly exported when it displays those kinds of artifacts.

edit : just saw your comment about no directional lighting, but i’ll leave what i was writing below too as scale could still be a factor and an easy check.

I don’t know that you can get away without a directional light. I’m not sure what information it has to go on for building Uvlighing if you see what I mean. The idea is that it will take the shadows generated from your light, and render them into your textures on objects for static light and objects. If you have not light, i’m not sure what it will build based on.

Just turn down the intensity of the directional light, and turn up the Indirect Lighting. It should be easy to see if adding back in a directional light if the problem goes away, and as you turn down intensity when it comes back. You can also turn down the Indirect intensity on the directional light too.

It’s an interesting problem, and i like your models.


I don’t know if all your problems are UV related, but there is definitely some UV issues here. The small roofed structure for instance, the area that large sections of your model have for lightMap UVs are tiny, there is lots of space between them, in fact some parts are so tiny there is more vacant space than space taken up by the model in the lightMap UVs. This one in particular is very questionable and should be remapped, and I would probably do this manually so you can take larger sections of your model and keep them together since it seems to really be fragmenting it. This doesn’t look like Maya doing an Automatic mapping, it looks very spread out for Maya.

So I would do this

1 ) Fix UVs on that small structure

2 ) Render tests alone in a test scene with a light so you can debug more quickly instead of in a whole game where you have to wait.

3 ) Increase the resolution of your UVs in UE4. You have it set to 256 now, but scroll down to your min LightMap Resolution in the LOD1 section. I seem to remember having to work with his too.

4 ) It actually sounds like there is a tolerance problem with your scene due to the fact that what you describe sounds like things being too close together are self shadowing or shadowing other things. In some software there is a way to change that tolerance, I don’t know about that with UE4, however, it could be that when you started importing into the game the size of your models is too small and you began assembling the game small (that’s my guess).

The way to test this out is to take something from UE4, a model from one of their game libraries, put it in a default game and EXPORT as a fbx. Import it into your modeling software. In your software you want to use this (could be one of their characters for instance) as your template for your world.

One thing I notice with modeling and importing into UE4, the settings of our export is very important. For instance, in Maya I like to work with my scale set to Feet. That way I don’t have clipping problems and can work in a scale that makes sense to my American sense of size. Then I set my preferences to Centimeters before I export my models to UE4. Once I do this, the scale comes in perfect for UE4 since that is what UE4 is expecting. If I export with Feet the model is gigantic I believe. I haven’t tried setting it to inches, so I don’t know what to expect, but it’s best to just match what UE4 expects.

Here are screenshots of normals. I see no issue. And as i said before… these are not hte only models that do it… hell that plant came from the unreal market. It happens with the vast majority of things in the scene that are only lit by indirect skylight with no directional light in the scene… this includes grass, stones, and plants along the floor. Some just show blackness where it should not show blackness… like a leaf pointing at the sky should not be really dark.

Alright let me try to respond to every point lol…

4.) Its at correct scale. No doubt about that. I usually match stuff up with meters or cm and match it to the size of what it would be like according to other unreal market assets… Heck some of the models in that scene are from the unreal market. So scale is on point.

3.)Shouldnt need high resolution on a flat wall… where the uvs are fine… Lets not worry about the roof top thing for now. We all know those uvs are ****, but i dont care about that since thats not the root cause of my issues for the rest of the scene.

2.) will wait to do that one… besides… i dont want a directional light. Its a rainy cloudy thunderstorm kind of day. Unreal has skylight for a purpose… and thast what im using it for. Sky light lights from all directions liek a sky… sort of like indirect lighting.

1.)again lets not worry about that roof top… the uvs are fine on the window wall and plant that we are testing with.

Thanks for the compliment… I am hoping some expert in lightmass or a developer comments on this … hopefully there is a setting to use… i hate lightmass so much. Its weird to feel like your using a next gen engine, but still be stuck with last gen technology while everyone else has moved on for the most part… baking for 8 hours just to see if u fixed something…

Actually, I’m not sure about that.

First, in-game vizualistion won’t give any useful info. You need to display vertex normal in editor window.

You are supposed to have multiple normals per vertex at seams. Instead you appear to have one set of them, although it is hard to tell for sure, because of enabled tangents and binormals. The faraway panel looks curved, and it definitely shouldn’t look that way.

Enable normals only and try again.

Check attachment to see what it should look like.

Yea i see no problems… here are 2 shots from both sides. normals only.