[Radiance-general] Any method to calculate sky view factor in Radiance?

[Germán Molina Larrain]

Hi Katsuya,

*Points *should be the name of a file containing the location (Px,Py,Pz)
and orientation (Dx,Dy,Dz) of your "illuminance sensors". Something like

0 0 0.8 0 0 1
1 0 0.8 0 0 1

Such case would represent two sensors, one on the position X=0, Y=0, Z=0.8
and one in position X=1, Y=0, Z=0.8... both are looking Up.

I would recommend you to also check tutorials on how the "cat" command
works (it is easy, though... it only prints the contents of a file into the
terminal) and about piping. That would give you a better understanding on
what that command is doing

Best,

El vie., 13 abr. 2018 a las 11:38, Katsuya Obara (<katsuya.obara at arup.com>)
escribió:

> Dear Raphael,
>
> Thank you very much for your answer.
> Since I am not familiar with Unix, may I ask you how I should write in
> Microsoft batch file for following part?
> cat points | rtrace -h -ab 1 -I uni.oct | rcalc -e 'SVF=$1;$1=SVF;'
> Especially, I could not figure out what points mean.
>
> Thank you.
> Katsuya
>
> -----Original Message-----
> From: Compagnon Raphaël [mailto:Raphael.Compagnon at hefr.ch]
> Sent: Thursday, April 12, 2018 2:38 PM
> To: Radiance general discussion
> Subject: Re: [Radiance-general] Any method to calculate sky view factor in
> Radiance?
>
> Hello
>
> A simple approach is to compute the illuminance level under a uniform sky.
> First define a uniform sky (uni.rad) like this:
>
> void glow sky_glow
> 0
> 0
> 4 0.318309886 0.318309886 0.318309886 0
> sky_glow source sky
> 0
> 0
> 4 0 0 1 180
>
> Note that the radiance value 0.318309886=1/PI This makes the illuminance
> value computed for an unobstructed horizontal plane equal to 1 and this
> matches in fact the SVF value!
>
>
> To compute SVF values for several points, then use rtrace with option -I
> like this:
>
>
> oconv uni.rad >uni.oct
> cat points | rtrace -h -ab 1 -I uni.oct | rcalc -e 'SVF=$1;$1=SVF;'
>
> where points is a file where calculation points are stored as:
> x y z xdir ydir zdir
>
> For instance using these three points you can check that SVF values are
> well computed as 1 for an horizontal plane and 0.5 for vertical planes:
> 0 0 0 0 0 1
> 0 0 0 0 1 0
> 0 0 0 1 0 0
>
> Of course SVF values are usually more interesting to compute for scenes
> containing objects... These should be defined in a scene file and then
> merged in the octree before doint the SVF calculations:
>
>
> oconv uni.rad myscene.rad >scene.oct
> cat points | rtrace -h -ab 1 -I scene.oct | rcalc -e 'SVF=$1;$1=SVF;'
>
>
> Hope this will help you!
> Raphaël
>
>
>
>
>
>
>
> ________________________________
> De : Katsuya Obara <katsuya.obara at arup.com> Envoyé : jeudi 12 avril 2018
> 01:54:46 À : radiance-general at radiance-online.org
> Objet : [Radiance-general] Any method to calculate sky view factor in
> Radiance?
>
> Dear all,
>
> I want to calculate sky view factor.
> Trying to find in google, I could not find solid information which I can
> refer to.
> Could anyone tell me what kind of approach I can have to calculate sky
> view factor?
>
> Thank you.
> Katsuya
>
>
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