There I have a setup from default cube and plane scaled to 100 units size, and default point lights placed in raws. You can see how light contributing to ground, creating indirect lighting from it, and this light contribute further to wall, resulting in weird pattern.
What can I do to fix/hide this behavior? On smaller scales I used r.Lumen.ScreenProbeGather.FullResolutionJitterWidth 8 to somewhat “enlarge” these patterns, so they just bleeding with each other, but it’s not an option for larger scales. I can also use r.Lumen.ScreenProbeGather.DownsampleFactor 64, but this way I’ll lose quality and when I get close enough to the wall, patterns will appear anyway with increased samples for close objects. I need more elegant solution. Any ideas?
This is fundamentally an issue with how lumen handles distant lighting, a lightsource that is very small, either because it is far away or because it is just physically a small light, will produce this effect.
In this context when I say “a light source” I mean literally anything in the scene that is bouncing light. It could be a wall reflecting light onto an opposite wall, not literally a light actor.
I find that the only real way to deal with this is to just make lights and any lit surfaces a lot bigger. The smaller the lightsource is the worse the quality will be.
After making the lights larger you can adjust the exposure to compensate for the increased brightness of the scene.
If you can live without it, you could set the indirect lighting intensity to zero, this will remove bounce lighting from those lights though.
thank you for answer, I got the idea behind it, you want to drown these splats, by making their background lighter. but it’s not really working, and it’s not supposed to. By making your light bigger you affect not only the pattern, but the surface you light directly, you make it brighter, look at left side of your video. So if you just turn down the overall exposure, the pattern will return, as if you didn’t change anything in the lights. Lighting the dark spots on the left side hiddens the pattern on the right side indeed, cause it based on it. But it’s unacceptable in such case.
turning off indirect lighting is rather better alternative, theoritecally, I can replace indirect lighting with one big rect light in such scene, it will produce nearly the same result as reference. but the idea is broken, if it’s not exactly this scene, or if the ground has multicolored texture in it. If I rotate rect light to light the surface, it starts producing light to it, so it’s not good enough. Still need more ideas.
That’s really not the idea. The issue is that the distant lighting is very high contrast and that shows in the indirect lighting. The goal is not to drown out the splats, it is to reduce the the contrast of the distant lighting.
It works fine, it’s just not ideal because it obviously changes the look of the lit surface.
what scale we talking here? i replicated the 8cd light grid. and… well… there’s lighting and there’s lighting. one is more stable than the other, in the lumen scene.
if you want to, you can just replicate scene from my screenshot. both plane and cube scaled to 100 units. Or you can modify your scene by removing the side walls, lifting your ceilling higher like 2x times, and slightly reducing the size of your lights.
you mean indirect? by drowning i mean exactly same behavior, as if you reducing contrast. my english is bad sometimes.
Yeah, avoiding the problem is not a solution. I want this small spot of light on the first screenshot of yours.
Sorry, didn’t get it from the first read. But I still thinking, that it’s not the fault of the dark spots on distant light, but it’s dark spots on the left, that causes them. I want left side to look like your upper screenshot, and the right side like your bottom one .
a 20 meter high ceiling? spacex level of height? still gotta balance the wattage cough candles with the bounced lighting.
you want a sharp light circle? then you could or should use spot lights with an inner cone angle close to the outer angle. point lamps are not the right choice for sharp ceiling lamp visuals. they are more expensive to render too and look like dated garbage in the grand scheme of thing. they are only good for open light bulbs or explosions. i reckon you’re new to the art of lighting things properly?
the type of light doesn’t matter. it’s just a problem that I want to be solved with no dependency of what scene I want to achieve. with dynamic GI based game, where light traversing through whole scene, this pattern can appear in unexpected scenarios, and there must be the way to handle or hide it.
shamy statement . it’s not a question about lighting the particular scene, if I want to, I can create my own lightmaps in other software to not deal with lumen. but I want to deal with lumen behavior here, with principles of how it works to get more control of the situation. I was mentioning cvars for a reason. It’s more coder question, rather than designers.
you know how cone tracing or hemisphere tracing works? it’s basicly random sampling the environment and accumulate light. on the big lamp you have more samples that hit the lit circle. on the small lamp you have maybe 1 or 2 that hit it. and the sampling pattern is random. monte carlo algo. the result is “normal”.
just don’t make your lights and lit surfaces too small. the lumen scene has a volumetric resolution. that’s the limiting factor. there is a cvar that can raise that detail. i don’t remember what it was called rn tho. sry
and well discard that statement then. you want code vision? then think about the algorithm. and howto deal with it’s limitations. yep
r.Lumen.ScreenProbeGather.RadianceCache.ProbeResolution
it’s not a sample count, that needs raising.
the amount of samples and traces playing not much a role. I don’t need my perfomance to be suffered. and this won’t solves the problem.
welp… i think i found your “problem”. it’s called overexposure. autoexposure can lead to uncontrollable lighting conditions.
under nominal lighting conditions it works just fine. i nuked the exposure for that screenshot. i even had to put a lil ambient light to see anything at all.
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. it’s not a question about lighting the particular scene, if I want to, I can create my own lightmaps in other software to not deal with lumen. but I want to deal with lumen behavior here, with principles of how it works to get more control of the situation. I was mentioning cvars for a reason. It’s more coder question, rather than designers.