Light Scenes
bueller1998_df4ca4b697
Posts: 161
I'm having this problem with lots of scenes including the Supermall. The characters are lit, but everything behind them is dark. Is there an easy solution to overcoming this. I have tried adding additional lights, usually after about 5 additional lights to the light set I am using I see some difference but not a whole lot. I usually like bright, happy scenes, but everything in Iray seems set to render very dark.
I've included a render. This scene is with the default lights that come with the Supermall. You can't see the mall.
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I beleive this set is from pre Iray times so the lights included will be optimized for 3DL so you probably need to adjust the lumen by adding atleast a couple of zero's to what is there already rather than just adding more lights
There are a few threads around with information on lighting indoor scenes - There is this thread that is not exactly the same issue but the tips there will help you get your scene how you want it
http://www.daz3d.com/forums/discussion/comment/1222561/#Comment_1222561
William, thanks for the tip. I tried that with a huge plane, but it didn't seem to apply more light to the scene. And, yes, I did make it emissive with the shader. Are there any settings that might work in such a large area like the mall?
When I am confronted with a situation like that I increase the number of watts/lumens (or whatever your setting) from the plane by something silly, like a ten thousand times, just to see what heappens. I do this because the amount of extra light required is often startlingly huge! Then its possible to adjust correctly from there.
Also, unless you have a really fast rendering setup, note that Iray does a separate set of calculations for light from each and every light source. So ten lights will mean a tenfold increase in calculations over that required for one light, and a considerable slowing of the render. You might also make sure the plane is emitting from just one side (and its the side facing down that is emitting - flip the plane over if necessary) as emitting both sides slows the render, then swith off all the other lights that are not contributing something good to the render.
I hope that helps.
I should add that the huge increase in light required is because of the way we perceive light levels. If you are in a fairly dimly lit room, lit by just one light, and you then switch on a second light of similar intensity to the first, you have double the light level, but it does not seem much brighter to the human eye. I'm not sure of the figures, but you might need something like ten times the actual light level to make the area appear doubly bright.
I understand that for a young person with good eyes, the brightest and the darkest light signal that the eye can sense are a factor of roughly 1,000,000,000 apart!!! So if the light level in the render is too low, don't be afraid to add a good few zeros!
That Suburban Mall scene is pre Iray, (optimized for 3Delight rendering ) and loads with a physical skydome. To use it in Iray, Go into the scene tree, and there's a folder called World, open it and delete the skydome in there and the UberEnvironment2 in there and then render with Dome and Scene and see if it brightens everything up. The ambient light from the sky will filter in through the skylight then.
Doesn't the emissive shader automatically shade both sides of the plane? It appears the plane has one material zone.
Thanks for the clarification FirstBastion. It's a beautiful scene. I hope I can make my renders look like yours.
No...
The light is emitted in the direction the normals are pointing...so that means, unless you flipped the primitive, the light is going UP. I believe there is a checkbox to make it doublesided...but really does increase render times.
Actually 10,000 times is EXACTLY correct...when switching between m2 and cm2. It's all about the units used as to whether the values are silly or not.
Wow, got the whole mall to render in Iray with a plane lit up with the emissive shader. But it all looks yellow. The mall store windows are showing up as green boxes which I hope to fix with an uber shader.
But what can I do about the yellow tint?
This is a 38% render after an hour. Thrilled to have the depth on this beautiful mall scene. Hope to neutralize the color.
My specs are a Titan Z and an nVidia 970. My core CPU processor is a 6 core i7.
Anyway, I envision a lot of stuff happening for me in some wide opemn scenes, especially a mall. Hopefulluy I can get the Iray lightin down.
Thanks to FirstBastion and those who can help.
Check the color temperature on the emissive shader...there are two things that will control the light color...the Emission Color and Emission Temperature (mine loaded at 2900K...a very orange-yellow light). Right below that is the two-sided option.
Thanks to everyone who helped me work through this. I now know how to light a scene with tremendous depth.
Here are the lighting results. Thanks to Will Timmons, Patroklos,First Bastion (the mall creator,) mjc1016, and Totalou, Mjc1016, you had me look up light temps to set it right. Will Timmins sugested the plane. Thanks again to you all!
Good to see you got it figured out.