OK, I'm an idiot.
I'm trying to create an area-light consisting of 3x3 light sources, but I
can see only one! (Not sure if the looks_like parameter should be applied
for each light source, but at least I expect to see 9 bright spots on the
box!)


=======================
code:

background { Gray70 }
box { <-500, -500, 0>, <500, 500, 1>   pigment { Gray70 } }

light_source { 0, White
    area_light 600 * x, 600 * y, 3, 3
        adaptive 1   jitter   translate < 0, 0, -20 >
        looks_like { whiteBulb } }

camera {
    location <-400, 200, -500>
    right 1.333 * x
    look_at <0 , 0, 010 >
    angle 50  }

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Le 19.08.2007 22:49, stevenvh nous fit lire :
> OK, I'm an idiot.
> I'm trying to create an area-light consisting of 3x3 light sources, but I
> can see only one! (Not sure if the looks_like parameter should be applied
> for each light source, but at least I expect to see 9 bright spots on the
> box!)
> 

http://tag.povray.org/povQandT/misconceptions.html#arealightconfusion2

Especially the third dot in the dotted list.


-- 
The superior man understands what is right;
the inferior man understands what will sell.
-- Confucius

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stevenvh nous apporta ses lumieres en ce 2007/08/19 16:49:
> OK, I'm an idiot.
> I'm trying to create an area-light consisting of 3x3 light sources, but I
> can see only one! (Not sure if the looks_like parameter should be applied
> for each light source, but at least I expect to see 9 bright spots on the
> box!)
> 
> 
> =======================
> code:
> 
> background { Gray70 }
> box { <-500, -500, 0>, <500, 500, 1>   pigment { Gray70 } }
> 
> light_source { 0, White
>     area_light 600 * x, 600 * y, 3, 3
>         adaptive 1   jitter   translate < 0, 0, -20 >
>         looks_like { whiteBulb } }
> 
> camera {
>     location <-400, 200, -500>
>     right 1.333 * x
>     look_at <0 , 0, 010 >
>     angle 50  }
> 
> 
> 
If you want 9 bright spots, you need to use 9 actual point_light placed in an array.

You use adaptive 1 with an array of 3*3. The problem is that adaptive 1 start 
with a 3*3 array and thus, adaptive have absolutely no effect in your case.
With adaptive, the benefits start at the following dimentions:
adaptive 0 -> 3*3	best with 9*9 and more
adaptive 1 -> 5*5	best with 17*17 and more
adaptive 2 -> 9*9	best with 33*33 and more
adaptive 3 -> 17*17	best with 65*65 and more

-- 
Alain
-------------------------------------------------
'I can resist anything but temptation.'

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Le Forgeron <jgr### [at] freefr> wrote:
>
> http://tag.povray.org/povQandT/misconceptions.html#arealightconfusion2
>
> Especially the third dot in the dotted list.
>

Great, I managed to overlook "The array-effect applies to shadows only. The
object's illumination is still that of a point source." in 3 readings.
Merci for pointing it out.



Alain <ele### [at] netscapenet> wrote:
> If you want 9 bright spots, you need to use 9 actual point_light placed in an array.
>
> You use adaptive 1 with an array of 3*3. The problem is that adaptive 1 start
> with a 3*3 array and thus, adaptive have absolutely no effect in your case.
> With adaptive, the benefits start at the following dimentions:
> adaptive 0 -> 3*3 best with 9*9 and more
> adaptive 1 -> 5*5 best with 17*17 and more
> adaptive 2 -> 9*9 best with 33*33 and more
> adaptive 3 -> 17*17 best with 65*65 and more
>

Thanks Alain. I guess I never thought about it.

Merci a tous

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