Le 18-03-16 à 15:17, Kenneth a écrit :
> clipka <ano### [at] anonymousorg> wrote:
>>
>> Actually, the safest bet is: Don't set radiosity brightness to
>> /anything/ other than 1.0 in the first place! It wrecks realism anyway.
>>
>> (A reasonable case can be made for brightness values slightly _above_
>> 1.0, when recursion_limit is set particularly low (2 or even 1), to
>> compensate for the fact that this reduces the overall brightness of the
>> scene a bit. But brightness values below 1.0 are of the devil. Don't go
>> near them.)
> 
> Thinking about this further: I assume you mean, when using a HDR light probe for
> the sky and no other lights in the scene? A brightness value of 1.0 would make
> sense.
> 
> Whereas, when using a typical LDR sky photo, and a (single) light in the scene
> for the 'Sun', a rad brightness value of 1.0 could be too bright, for various
> reasons.
> 
> Given that the objects in the scene have  finish {diffuse 1.0 emission 0} --
> with ambient turned off automatically-- and a light_source of rgb 1 (or more
> likely less than that), it would *seem* natural to turn down rad's brightness
> below 1.0. So that any object surfaces never exceed a surface brightness of 1.0
> max; otherwise, there's a danger of washing out the object colors. It would all
> depend on how bright the single light_source is: if it's set to rgb 0.6, then
> rad brightness should not exceed 0.4, according to my theory.
> 
> Of course, this all depends on light_source/surface brightness and rad
> brightness being simply additive (i.e., the combination can go beyond 1.0.)
> That's what I've always assumed, anyway.
> 
> However, I do see a major problem with my argument: The parts of the scene in
> *shadow* are only receiving the rad lighting-- and such shadow illumination
> would *vary* depending on my light_source brightness. Not very logical, I admit.
> (Or more specifically, not 'realistic.')  So I guess such a lighting scenario
> is, by default, not 'realistic'  at all, but just an attempt to make the scene
> 'pleasing to the eye.'  I.e., balancing 'Sunlight' brightness against shadow
> brightness, just to prevent any colors from being washed out.
> 
> 
> 
> 

The best way to go when a light probe is to bright or dark is to adjust 
it's emission down or up respectively. Don't play with brightness.

Next, you can adjust the diffuse part of your textures. Most of the 
time, the default of 0.7 is correct, but at times, you may need to use a 
slightly smaller value. It don't get bumped up to diffuse 1 when you use 
radiosity, only ambient get turned off.
With radiosity scenes, default is :
finish{diffuse 0.7 ambient 0 emission 0}

Alain

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