[Radiance-general] Modelling sky using sky scanner MS-321LR

[Ehsan M.Vazifeh]

Dear Lars,

As I understood correctly I have just distribution of diffuse using sky
scanner. So I need to include the sun separately. Now I have two questions:
1) what is 10 real arguments in the sky scene generated by gendaylit (below
you will find the example)

void    brightfunc    skyfunc
2    skybright    perezlum.cal
0
10    3.114e+01    2.426e+01    -0.989445    -0.210729    22.988    -5.9264
   1.398847    -0.010398    -0.415479    0.909543



2) why when we generate a sky for instance with sun description, we should
always include the sky scene as a glowing source otherwise the illuminance
values will be zero.

I guess I have some fundamental misunderstanding about the sky scene
description. It would be real help if I can get some explanation why this
happens.

CHeers,
Ehsan






On Mon, Apr 7, 2014 at 11:05 AM, Lars O. Grobe <grobe at gmx.net> wrote:

> Hi Ehsan,
>
> as far as I understand the scan pattern used by the scanner is close
> enough to the Tregenza patches to use it with dctimestep and daylight
> coefficients. To get an idea of the format expected by that tool, have a
> look at the output of gendaylit.
>
> Be aware that the sun is excluded in the measurements, so you will have to
> find a way to get the direct sun contribution. As there are no "color
> channels" in the measurement, you would use the luminance readings and
> apply them to all three channels in Radiance equally (R=G=B).
>
> Cheers, Lars.
>
>
>  Dear All,
>>
>> I try to model sky and daylight using measured data from sky scanner.
>>
>> I want to know is it possible to convert radiance or luminance of each
>> patch to rgb and use 145 primitive of type source to model the sky? or my
>> assumptions are wrong?
>>
>> Cheers,
>> Ehsan
>>
>
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