I’m trying to figure out how to push more indirect light into the room. The conditions are an overcast day, so only skylight is in play. Now, as seen in the screenshot, the smaller room is pitch black, so is there any way to make skylight bounce in there? My indirect bounces in the World properties are maxed out. I tried setting my Indirect Lighting on the skylight to ridiculous values, but instead of bouncing light further, it blows out already lit areas. I also tried setting up post process volume for the room and maxing out indirect lighting in GI section, yet it still just boosts contrast.
Now, if the interior is a separate level, then of course spotlight/reflector plane combo is ideal, but how to deal with situation like this where exterior and interior must use the same lighting conditions?
Sorry if it sounds like the worst case scenario, but if you think about it, such conditions are not that rare.
There are actually a number of things that could help here, but the one thing to keep in mind is that the bounce lighting is based off the actual physics of lighting and the materials you are using in the surface. So, a very direct answer to your question is that you cannot directly increase how far the bounce goes. You can however tweak some of the lightmass world settings and get a better quality bounce and remove some of the stark blackness I am seeing in your picture.
Open the World Settings and roll out your Lighmass>>Lightmass Settings and take a look at your Environment Color and Environment Intensity. If your Environment Color is black change that first to a lighter color (usually a tone of your predominant sky / level color). Usually this setting alone if you are using sky lights and reflection capture actors will be enough to brighten the darker nooks and crannies in a level. If it is still too dark I would slowly increase the Environment Intensity until the shadows lighten to your needs.
Remember after each setting change you will need to rebuild lighting.
Thank You
Ketchum
EDIT: Also remember that by default the engine uses Eye Adaptation in levels, which causes the darkening of shadows when in brighter, more direct lighting and lightens shadows when in dimmer and less direct lighting. You can completely remove this effect through an unbound global post process volume and setting the Min and Max values of Auto Exposure to 1 and 1 (equal values remove the effect, lower values brighten the entire scene and higher values darken)
Thanks for your answer. Eye adaptation is not a factor here, it is fixed at 1. As for Environment intensity, I did try that but it has no effect. Which sort of makes sense. If I understand correctly, Environment Light is basically a skylight with no direction. Thing is that in this very extreme case, the second room is completely occluded, so even Environment Light cannot get in there (just tried it pure white with 100(!) intensity and got complete blowout in the lit areas, still pitch black in the far room).
I did the test rendering with Corona renderer in max, and logically the results were fairly close (of course, offline renderer is more accurate). So to solve something like this, the only thing I can think of is using something like Mental Ray’s “skylight portal”, which takes environment light and “forces” is into interior. In UDK, emissive plane in the doorway would act like something similar, but in Unreal 4 that’s gone, for now (4.6 has only direct emissive, which in this case is pointless).
Will try, thanks, but I highly doubt that roughness has anything to do with light bouncing. I think only texture luminosity defines how much light it bounces back. I’ll keep playing around, maybe will find some solution.
IIRC, the skylight uses only one indirect bounce. I’ve encountered situations similar to yours where more bounces would help, but I guess it is up to Epic if they want to allow it (it’s probably capped at one bounce to keep build times short).
What I do in these situations is overcrank “Indirect Lighting Intensity” while simultaneously decreasing the direct “Intensity” value. If your exposure settings are constant it shouldn’t take too long to settle on good values.
Try using an indirect value thats 50-100x that of your direct value. (Note - this can tend to produce blotchy baked AO results, but if you’re trying to use a minimal number of lights, this can help.)
