Needing guidance with shadow/lighting artifacts

Hello everyone! I’m new to unreal engine and im trying my hand at arch vis lighting. I’m having issues however with artifacting. Im using strip lighting in doorways and near the ceiling that i have wedged between a little lip i made and the wall so that you cant directly see the light but rather just what its casting against the ceiling/doorways. I’m also having issues with my reflection captures creating these visible circles on the walls. changing the reflection capture intensity doesnt seem to help much, they are still visible. I’ve placed dynamic portals over all windows as well as well emissive lights. my static lighting level scale is set to 0.5 and setting it to 0.1 makes it worse. I’m getting shadow artifacts in the doorways and light artifacts on the couch and octagonal room. these pics were taken in preview mode but when i bake in production it makes the artifacting even worse in some areas. it looks like a disco ball effect in one of the rooms on production quality. I’ve also changed the lightmap resolution of all walls/ceiling/flooring to orange. Thanks in advance for any advice! cheers


I don’t know where to start… :S …maybe you should watch/read more tutorials about the subject?
…if you’re after archviz: you’ll need to go with 0.1- 0.15 with level scale /basically 1- 1.5 mm accuracy!! 0.5 is half a centimeter!!/ and also RED lightmaps!!

In a scene like this you should rely more on box reflection captures!! …I think if you’d put just 1 large sphere one (covering the full area) into this scene, those circular marks should disappear…

There are lack of samples in your scene! Could be the preview mode, could be low res lightmaps, could be compressed lightmaps, could be no importance volume, could be no portals, could be low lightmass quality settings…

Also I don’t know how your walls are built but the best results you can get with corner snapped walls with thickness!

…if you could share your settings like what lights you’re using and your lightmass settings…

I’m not as into baked lighting as others in the forum, but I think I could point out at least a few areas that you can test and improve things. One of the things I notice is the crinkling around the doors and in other shadowed places like the corner edges where walls meet ceiling and similar areas. That is definitely a lighting issue, and also a shadowing problem, not one or the other. It is not merely caused by low mesh resolution or lightmap resolution specifically. A particular feature to check in your case could be the volumetric lightmap if there is one in the scene.

To put it bluntly, you need to provide more information about your entire level which is in the screenshots. Here are several aspects to include in the info for helping others help you:

  • Lightmass settings under World Settings (found in Settings in the viewport)
  • Redo the screenshots with your reflection captures visible and their bounds / influence radius visible
  • Post Process Volume settings for Light Propagation Volume, Screen Space Reflections (if enabled), and the main PPV settings (Priority, Blend Radius, Weight, etc)
  • Some of the settings for Skylight and/or Directional Light

That’s a lot of info to provide in a forum post, all in screenshots. So, instead of using only screenshots, put them in all in unordered lists with headings that correspond to the actor / object that the list is about. Without that info, it’s more of a vague guess when trying to compare and contrast all the different artifacts in your screenshots.

One question I have is where are the portals you said you put by the windows exactly located in reference to the interior? Inside the interior, within the window frame (between interior and exterior), or immediately outside the window (exterior)? and what are the size / basic settings of those? Lots of the documentation for various features are written for older versions of Unreal Engine, so it really can be misleading as far as getting some things to function correctly. Yet those docs do contain a number of essential concepts and pieces of information that are applicable.

okay thanks for the help guys really appreciate it! ill link the stuff below in pics. For the record the building model that I’m using for this was made in sketchup and ported over in datasmith, not sure if that matters. I realize i need to increase my reflection capture radius to get rid of those circles, but ill still include pics of them and their current radius. my portals are positioned on both inside and outside of the window. each window is essentially sitting in the middle of the portal, so half of the portal is on the inside of the window and the other half on the outside. also Screen space reflections arent enabled on my PPV. I’m new to this forum so maybe you can tell me how to do these unordered lists with headings. for now though I’ll just let you know that the first 4 pics are reflection orbs and their radius, the 5th-10th pictures are directional light settings, the 11th-16th pictures are PPV settings, and last but not least, the 17th-20th pictures are skylight settings. excuse me for not knowing how to organize these. thanks again!

This is from the Unreal documentation…

**RED - **Large radius. Reflects bulk of the level and the background.
**BLUE - **More localized reflection. Captures individual rooms.
**GREEN - **Detail reflection with small radius. Placed in areas where small important details are required.

I wouldn’t touch indirect lighting intensity in any of the lights’ settings: it can mess up the scene and proper lighting can be achieved without changing this!
I also wouldn’t turn on any extra lighting effect in PP till my lighting is correct… keep the static exposure and ditch the rest…
The rest is kind of irrelevant…

…if you could post your LIGHTMASS settings: they are the most important!! + your lightmap resolutions of your bigger meshes like walls, floor…

  • if your walls are overlapping or face/polygon snapped or properly corner snapped…

I looked at the photos, and saw a number of things to try:

  1. A few reflection captures (sphere of influence) are intersecting with walls and geometry in the interior. In one photo, a part of the sphere is jutting past the wall in a hallway,but the capture is on the other side of that wall in a different room. Re-locate it so it’s not intersecting with any of the geometry, and resize those in addition to relocating.
  2. The skylight’s indirect intensity is really high! I understand because of the type of dim yet diffuse lighting you’re trying to achieve, but try decreasing it to 2 or 3, or even 1 to see what happens to the shadow/light artifacts. It may be it needs a test to use process of elimination and find what is actually causing it in conjunction with the indirect intensity set to 5.
  3. The reflection captures receive and distribute some of the light, from what I understand, so having them disturbing the geometry or intersecting it is likely causing some of the circles of lights. In the basic tutorial about them, it’s said that it’s a best practice to prevent the captures from touching or overlapping walls and objects to be reflected in the scene. So try to isolate their spheres of influence from the surrounding geometry and small-scale lights. Placing one around the entire scene is different, so I don’t know what effect that’d have…besides I’ve seen it suggested in the docs and forums numerous times.
  4. In the directional light settings, Source Angle at the top is default (0.5357), whereas down in the Lightmass part of its settings, Light Source Angle is 1. This might be causing inconsistencies in lighting and shadowing, though I’m not certain it is. To test, set one to the same value as the other, and rebake lighting.
  5. Your directional light is stationary, so the indirect lighting is static, and not dynamic. Distance field and cascaded shadow maps are both disabled in it, so it is not using those to generate shadows. So it may be the shadow artifacts are stemming from Dynamic Shadow Distance Stationary Light set at 0 (which is disabling dynamic shadows for a stationary light). The scene may need cascaded shadow maps, or in other words, set Dynamic Shadow Distance Stationary Light to a value equal to or greater than the total size of the interior scene. So if the house / building is 10,000 units long and 5,000 units wide, set the Distance to 11,000 or higher. Then, according to how I read the docs numerous times, the shadowing gets results that blend with the lightmap shadows accurately.
  6. Set the PPV Blend Weight to 0 to see what happens. I had an issue where my PPV was surrounding the geometry of the scene, was bound, and I had these shadow artifacts on the outside of the walls. When I increased the blend radius to 1000 for the PPV, it removed the artifacts. Basically, something on the outside of the PPV was blending into the PPV and with the scene, causing the artifacts. So, setting blend weight to 0 disables the blending of the PPV with outside influences, whether of light or textures, and can get rid of artifacts.
  7. In the skylight, enable “Affect Translucent Lighting” and “Transmission” (both for the windows mainly since they’re transparent and transmit light). Try enabling “Cast Ray-Tracing Shadows”. Click Recapture after each change and before every bake.

Thank you guys so much for all this feedback! I really appreciate you taking the time to reply to me, its really helpful. I’ll troubleshoot and try out what you guys said and let you know if it fixed it, thanks again!

Also, yes I’m sorry I totally forgot to post lightmass settings amid all the others, there they are. I’ll try to get some pics later of the lightmap resolution of the bigger walls etc when im at my computer later, all i know right now is they are all in the orange. I know you said red but the tutorial i was watching had their lighting come out how I’m trying to achieve and they were using orange lightmap res on walls etc. so it must be some other settings I have going on that are messing with it or walls not snapping correctly like you were sayin. I’ll also take wireframe shots of the walls to see if they’re overlapping!

PS. thanks for that reflection capture documentation! that makes a lot more sense

Amazing, thanks for putting this all into layman’s terms because usually when people say to change something its coming from someone much more experienced and doesnt translate well!
I noticed that the directional light is stationary, what if I changed it to static? Would that make it bake lighting better along with changing the other settings you were saying for it or should I just change the values you said and leave it stationary?

What version are you using?

Sure you chose the look and your settings!! Higher resolution lightmap = higher detail…
Turning off lightmap compression makes a big quality change, I’d advise you to do so!
If you want sharper lighting detail you should also go lower with (IL)Smoothness (0.6)! The higher you go the more Unreal blurs out the actual result!
Going higher with (IL)Quality helps to get rid of those blocky/patchy/dirty areas while keeping detail!

i’m using 4.24, ill leave the directional light stationary then and try setting those other settings for it if nothing else works by process of elimination haha

awesome! sounds good. I’ll prob do that when I’m getting closer to the end build because im assuming that ramps up bake times by doing that? I’ll keep it in mind, and report back to this forum if I still can’t find the issue after trying everything that you guys have suggested

okay, well I think ive narrowed it down largely to the emissive strip lights i have set up. how would you guys go about fixing this? ill include pics below where i decided to just use a pre-done arch vis scene and gut it out to leave just the room to test lighting on and found that if i set up point lights and emissive strip lights to compare the results. I dont have any skylight and my PPV and lightmass is the same as my other project. ill also include my master material with its instance material settings included in pics as well as the cube’s lighting settings i used to create the strip. the emissive light seems to create the light/shadow blotching that I cant seem to find the solution to. it also seems to create the blotches if you look closely on the windows frames, to the right of the window all the way on the opposite side of the room, as well as in the corners where the walls meet the ceiling with only that one emissive light above the front doorway emitting light. The spot lights by themselves create much better light and shadows and dont seem to blotch. All the pics were taken with a preview mode bake. Thanks guys!

This is not right.
Stationary lights bakes indirect portion of the light to lightmaps. Direct part is evaluated dynamically but shadow map is baked for direct light.

Yeah, that’s correct. I switched those around when I was typing it in, and misunderstood the tooltip for it. So stationary doesn’t bake direct, and bakes indirect.

One question. Why is the crinkling and blotchiness occurring mostly near the ceiling, around windows, and in side corners (wall to wall corners)? It’s not occurring much or at all in places near the floor (wall to floor corners). It can even be observed in the wall lights going further from their initial location down to the floor. It’s kind of a gradual transition in quality from bad to somewhat good.

I think its because in the pic where it’s facing the windows it doesnt show up as much near the wall to floor corners as the one facing the door because there are spot lights still on the walls near the windows directed to the floor, so I think its reducing the effect the strip light has on those edges because its melding with the light being cast by the spot lights. There are no spot lights directed towards the ceiling in the room at all, so prob why its showing up more on those corners. any idea on why these emissive materials have such bad artifacts occurring?

Are your emissive surfaces covered with portals?

heyo, I didnt at the time taking the pictures, but I went back and put portals over all strip lights and it didnt fix the artifacting