Light Intensity

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StompinTom
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Light Intensity

Post by StompinTom » Sat May 03, 2008 3:11 am

before i start doing tests, does anyone have any examples of how light intensity is distributed over a mesh?
i know when you enable Efficacy Scale then bigger meshes will appear darker due to the energy being distributed over the whole mesh. is this so for simple RBG/Gain?

can there be an option of something like "W/m^2" or something so that you can keep the relative light intensity between different emitter sizes?

also, if im using RGB/Gain, does anyone have a good ballpark for adjusting the Gain so that the lights are balanced with daylight/sunset?

thanks!

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Zom-B
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Re: Light Intensity

Post by Zom-B » Sat May 03, 2008 4:03 am

StompinTom wrote:does anyone have a good ballpark for adjusting the Gain so that the lights are balanced with daylight/sunset?
Add in env map, and you are pointing at the most complicated usability "issue" in our lovely and quite simple to use Indigo :)
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StompinTom
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Post by StompinTom » Sat May 03, 2008 8:29 am

haha! itd be cool to know what the units for Gain and RGD correspond to, if any! cuz then you could chart all the relative intensities and not spend hours mucking about balancing your lights.

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jurasek
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Post by jurasek » Sat May 03, 2008 5:54 pm

something like yhm yhm multilight would solve the problem ;)

greetz,
jur

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OnoSendai
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Post by OnoSendai » Sat May 03, 2008 6:01 pm

The units are spectral radiance, Watts per steradian per meter cubed :)

BbB
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Post by BbB » Sun May 04, 2008 9:30 pm

I see :(

StompinTom
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Post by StompinTom » Mon May 05, 2008 2:03 am

haha! ill have to google that shait.

in the meantime, a gain of about 12 000 works for getting your emitters balanced somewhat OK with the sunlight,, when its near sunset at least.

camera tonemapping with this works at ISO 100, f11, 1/125

hm ill look into tabulating this or something...

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OnoSendai
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Post by OnoSendai » Mon May 05, 2008 2:22 am

I'm planning to add Luminous emittance (http://en.wikipedia.org/wiki/Luminous_emittance)
as an option for emitters in Indigo as well.
This is a measure which means that a larger light will emit a greater radiant flux, and the amount emitted per unit surface area will be independent of the size of the light.

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Zom-B
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Post by Zom-B » Mon May 05, 2008 2:32 am

This sounds good master Ono...!

I hope this one goes fine with Reinhard... :/

Is there any "normalisation" betwenn the light "classes" involved too?
Can we finally have a env map lightened scene get working with blackbody & RGB emitter without 1001 test renders to tweak everything?
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OnoSendai
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Post by OnoSendai » Mon May 05, 2008 2:41 am

Perhaps I could make a setting to normalise the env map to a given average spectral radiance.
After that you could just pick a value like the spectral radiance of some representative sky direction at a certain time, and plug it in.

StompinTom
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Post by StompinTom » Mon May 05, 2008 5:46 am

that sounds real cool!
Luminous emittance would be perfect and normalizing env maps is gonna make scene setup so much easier!

crojack
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Post by crojack » Tue May 06, 2008 10:56 am

ZomB wrote:1001 test renders to tweak everything?
I thought that was just me :)

the world just became a lot less lonely

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