Any tips on indoor lighting ?
AJ2112
Posts: 1,417
Personally for me, outdoor lighting has an easy learning curve, hdri, sun/sky produce fabulous global lighting, also noticed outdoor lighting renders very fast. Indoor lighting has been a major challenge for me, scenes appear dark and take forever to render, have to add alot of lights or add countless zero's to lumens, using Iray. Some indoor scenes look much better using AoA lighting/3Delight opposed to Iray.
Any tips on indoor lighting with Iray. Thanks.
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The first thing to think about...the default settings for the camera are set for that outdoor lighting. So things like ISO, shutter speed, etc are all wrong for indoor lighting...so unless they are adjusted you have to up the light sources to match outside levels.
That said the units you use on those lights matter...watts is a unit of power and others are scale dependent (so is falloff...and Iray lights have a realistic falloff).
It at least partly depends on what sort of indoor your talking about. If it has windows I want that "natural light" as part of the lighting in the room. I'll also use some mesh lights to fill it out more often than emissive light sources. They just seem slower to me. Always be sure that your using the correct sort of settings for tone mapping. Your going to need at least a 200 speed ISO and that would be for a bright space like a well lit museam. Homes tend to be darker so you may need 300 or 400. There are other tone mapping options of course but that is where I tend to start.
Hi thanks for replies/tips. Didn't know I can set watts. I use exposure value alot, but haven't tried ISO. Noticed removing ceiling helps alot, but some lights are attached to ceiling, so ceiling removal cannot be done. Also, noticed to many white props, causes alot of graininess. Guess, I'll just have to experiment.
I've also been struggling with indoor lighting in Iray. The trouble seems to be that Iray lights don't "fill in" the shadowed areas as well as lights in, say, Octane do - so you have to compensate for that if you want your figure well lit (if you're just lighting a room then its not so much of an issue, but stick a figure in it and it becomes much harder to create realistic looking lighting).
Heres a few things I've picked up about Iray lighting that might help:
1) For soft, natural looking light create a large plane primitive and apply the Iray emissive shader to it. Adjust the temp and lumin to your preference and then use it as a general light source in your scene (either stick it on the ceiling or somewhere out of the way - make sure its facing the right way!). Its basically a substitute for the Iray dome indoors. These do an excellent job of filling in those dark shadowed areas that other light props or photometric lights miss. They are also extremely fast lights to render. These kind of lights usually create most of the "ambient" lighting in my scenes and then I add emissive props for highlights.
2) Photometric spotlights and point lights have a tendency to make things look a bit fake, in my opinion. I try to avoid them where possible. If you do use spotlights then I advise changing their geometry to make them large shapes (at least 100x100) in order to soften the shadows.
3) As others have said, adjust ISO for indoor scenes to brighten things up. I usually go for about 400 and then adjust from there.
4) If there are windows in your scene then the Iray environment dome can do a great job of providing ambient lighting from outside, especially at higher ISO levels. If you want to brighten this effect then increase the ISO - don't change the environment intensity that'll really intensify the blue colour. If you want the ambient lighting from the dome less blue you can also then adjust the ss red-blue tint. The only problem with this is that it can take forever to render because the light has to penetrate the window textures.
5) In real life you can light a room pretty well with a single light source. Iray, unfortunately, does not handle this so well, despite being physics-based. Basically, unless you're doing a scene with intentionally moody lighting then you're going to need several light sources in the room. Adding emissive table lamps or wall lamps at regular intervals can really help this, depending on the size of the room. You have to be clever with their placement though, otherwise they can overlap and cause conflicting shadows, which looks horrible.
6) Bear in mind that the state of the room, in particular the ceiling, floors and walls, will impact heavily upon the lighting. Rooms with dark, matte walls and floors are much more difficult to light than those with white, glossy walls and floors because you get far less light bouncing off the surfaces.
Personally I'm looking at maybe investing in this http://www.daz3d.com/iradiance-hdr-mesh-lights-for-iray in an effort to improve my indoor lighting. So far good HDR lighting seems to be vastly superior to anything I've been able to create myself, but as I understand it you can't use HDRs to their full extent on an indoor scene (particularly one without windows) because they're plugged into the Iray dome. I'm wondering if those DT mesh lights would solve that problem for me...
Since emiisive properties are dependent on the size of the mesh I would use Lumens only and try to keep the lumen count to realistic settings. Then once that is done play with the Tone Mapping settings.
My advice is to first change Tone Settings to values appropriate for regular indoor shoots (look up appropriate values -- something like ISO 800 and Shutter 64 seems at least in the ballpark).
Then you know at least what 'appropriate' is for your lighting.
I highly recommend using point lights or spotlights with geometry instead of emissive objects -- they render much faster. You can set a point light as a sphere and use it as a 'bulb' in a lap, or a bubble light fixture in the ceiling, or whatever.
I would then start with a single light, up the light level until it looks like the room is lit by a single bulb (dimly, but visible). Then place more 'bulbs' at the same value (or Duplicate)
Another thing to set is Render Settings > Optimization > Architectural Sampling: On (apparently better for low light/closed situations like this)
Use Finite Box with an indoor HDRI in the environment map. Resize the dome to fit the room set it to Dome and Scene, and turn off Draw Dome. Set the environment intensity and Tone Mapping to get the Ambient light you want and then add the lights you want at the settings you want and then readjust the tone mapping settings and environment intensity until the scene is lit the way you want it. The dome size is in meters so 2 meters for the height should bring it below the ceiling height of a normal house. If it is a large building then adjust the height to suit. If you only want the ambient light to come through a window then use finite dome with an outside HDRI and resize it to just bigger than the room size and increase the intensity until the light is usable, The other way is to use the sun and sky only and get the sun in a position to shine through the window directly. This can be fiddley but should be doable. The architectural shader can work too but I find it can make the walls and floor too shiny and glassy looking.
I find there are lots of different ways and combinations and it is mostly trial and error until something works.
Oh wow ! thanks everyone, fabulous tips/suggestions. Time to burn up more brain cells, Lol !!
"resize the dome to fit"... damn. That never even occured to me. Has anyone else done this?
These lights are surprising slow....and don't always react the way I expect.
People seem to report that emissive surfaces are slower, and that's what these are. Add an HDR image to that and well... I guess the calculations do kind of go through the roof. They won't speed anything up, that's for sure.
Thanks for the tip - I'll try that out
.
I thought that might be the case, but I don't mind so much about speed as long as they improve the lighting. Its the "don't always react the way I expect" part that worries me most. Thanks for letting me know though.
The true test of a renderer:
http://hdri.cgtechniques.com/~sponza/files/
Put your figure in the first floor but keep the sun from directly lighting it. No additional lights used, just pure indirect light/bounced rays from GI.
I have found that render times are improved if you deliberately overlight an indoor scene somewhat, then use the tone mapping settings or post work to reduce the light to the level I actually want. I think this helps because the dark areas 'converge' more quickly the less, well, dark they are. If you have a photography background this probably makes you feel queasy or like your cheating, but I fight back the nausea.
I have also found that completely closed interiors are the worst/slowest: if you can remove the ceiling, wall or walls that are out of shot, I think logically the light is allowed to 'escape' rather than bouncing around endlessly. Of course this is also a bit of a cheat, and works less well if you have an external light source, although it has worked OK with a very low intensity sun-sky or HDRI to provide some ambient light. Also I remove any objects that are out of shot, unless I think they have an important effect on the image e.g. as a source of reflected light. Plus, windows that are out of shot don't need glass if it's just plain clear glass, so I remove it.