[Radiance-general] Three-Phase Method _ Sky Vector - Daylight Matrix

[urtza.uriarte at upc.edu]

  Hi Germán,
Thank you very much for explanation. Now I have more idea of the
Three-Phase Method.
I do not know how the sky rotate, but, I will check Sky Vector's
parameters.
Kind regards,
Urtza.

Germán Molina Larrain <germolinal at gmail.com> escribió:

> Urtza,
>  
>     REGARDING QUESTION 1.
>      
> The CIE Overcast sky is simetric and independent of the date and
> location. That means that it does not matter if you rotate your model
> and the sky or change the location and the date, it will always return
> the same vector when fed into genskyvec.
>  
> Genskyvec approximate the sky as "finite elements" of constant Radiance.
> I understand this is done using Ray-tracing. That means that each patch
> (element of the sky vector) will have a different value that correspond
> to this approximation.
>
>    Finally, the sky vector does not depend on the model just as the
> sun's position does not depend on the orientation of your apartment.
> However, I understand it is possible to calculate a rotated sky vector.
> This is faster than performing all calculations again with a rotated
> model (i.e. if you rotate the sky clockwise, it is the same as rotating
> the model counter clock wise).
>
> REGARDING QUESTION 2.
>  
>    Klems divition is always the same divition. However, the direction
> used to trace rays (for sampling and calculating the View matrix) will
> depend on the orientation of the window. This is the same as saying that
> the same camera will give you different images if pointing on different
> directions.
>
>  
>    I hope I understood your questions and that my answers help
>  
>    Best,
>  
>    Germán
>
>
>    2015-07-03 6:44 GMT-03:00 <urtza.uriarte at upc.edu>:
>
>> _Dear experts,
>>
>> I am trying to learn three-Phase Method for Simulating Complex
>> Fenestration.
>>
>> I have two questions of Sky Vector and Klems divisions of Daylight
>> Matrix:
>>
>> 1) Sky Vector:
>> I am trying with Overcast Sky. I have done as following for Windows (I
>> have Ubuntu 14 now, but, I am checking the first steps done by Windows):
>>
>> gensky 12 21 15 -c -B 0.55866 | perl c:/radiance/bin/genskyvec.pl[1] -m
>> 4 -c 1 1 1 > review/skies/12_21_15.skv
>>
>> (I do not know if is good) So, I am sure that for each time during the
>> year it generates the same Sky Vector. However, I think that the
>> "genskyvec" calculation divided the sky in different parts in contrast
>> with "gensky" command that generate void brightfunc material.
>> Therefore, the skyvector does launch different values for each sky
>> division? If I rotated my model I get different illuminance date for
>> only Sky Vector variable?
>>
>> 2) Klems divisions of Daylight Matrix:
>> When there is a definition of "kbin(Nx,Ny,Nz,Ux,Uy,Uz)", is it because
>> for each orientation there are some different values? I suppose that
>> for each orientation it uses the same divisions.
>>
>> Excuse me, but, I am trying with a rotated model and I want to ensure
>> that I understand well the method. Sorry for the inconvenience. Thank
>> you in advance.
>> Your faithfully,
>> Urtza._
>>
>>  
>>
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>>  



Vínculos:
---------
[1] http://genskyvec.pl
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