# 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

···

____________________________________________________________
Electronic mail messages entering and leaving Arup business
systems are scanned for viruses and acceptability of content

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:

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:

cat points | rtrace -h -ab 1 -I scene.oct | rcalc -e 'SVF=\$1;\$1=SVF;'

Raphaël

···

________________________________
De : Katsuya Obara <[email protected]>
Envoyé : jeudi 12 avril 2018 01:54:46
À : [email protected]
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

____________________________________________________________
Electronic mail messages entering and leaving Arup business
systems are scanned for viruses and acceptability of content

1 Like

Dear Raphael,

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:[email protected]]
Sent: Thursday, April 12, 2018 2:38 PM
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:

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:

cat points | rtrace -h -ab 1 -I scene.oct | rcalc -e 'SVF=\$1;\$1=SVF;'

Raphaël

________________________________
De : Katsuya Obara <[email protected]> Envoyé : jeudi 12 avril 2018 01:54:46 À : [email protected]
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

____________________________________________________________
Electronic mail messages entering and leaving Arup business systems are scanned for viruses and acceptability of content

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 (<[email protected]>) escribió:

Dear Raphael,

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:[email protected]]
Sent: Thursday, April 12, 2018 2:38 PM
Subject: Re: [Radiance-general] Any method to calculate sky view factor in

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:

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:

cat points | rtrace -h -ab 1 -I scene.oct | rcalc -e 'SVF=\$1;\$1=SVF;'

Raphaël

________________________________
De : Katsuya Obara <[email protected]> Envoyé : jeudi 12 avril 2018
01:54:46 À : [email protected]
Objet : [Radiance-general] Any method to calculate sky view factor in

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

____________________________________________________________
Electronic mail messages entering and leaving Arup business systems are
scanned for viruses and acceptability of content

_______________________________________________
[email protected]

_______________________________________________
[email protected]

Also, substitute the ‘type’ command for ‘cat’ if you’re on Windows. At least back in the day, that was the only substitute. Maybe on newer Windows systems there’s a cat available.(?)

···

From: Germán Larrain <[email protected]>
Date: Thursday, April 12, 2018 at 7:27 PM
Subject: Re: [Radiance-general] Any method to calculate sky view factor in Radiance?

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 (<[email protected]<mailto:[email protected]>>) escribió:
Dear Raphael,

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:[email protected]<mailto:[email protected]>]
Sent: Thursday, April 12, 2018 2:38 PM
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:

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:

cat points | rtrace -h -ab 1 -I scene.oct | rcalc -e 'SVF=\$1;\$1=SVF;'

Raphaël

________________________________
De : Katsuya Obara <[email protected]<mailto:[email protected]>> Envoyé : jeudi 12 avril 2018 01:54:46 À : [email protected]<mailto:[email protected]>
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

____________________________________________________________
Electronic mail messages entering and leaving Arup business systems are scanned for viruses and acceptability of content

Hi Katsuya

Yes German's explanation about the content of the point file is right.
If you plan to use Radiance extensively, I really advise you to start using it on a Unix/Linux system for instance by installing a Linux virtual machine on your PC (I am personally using a Ubuntu Linux system running in VirtualBox https://www.virtualbox.org). I am sure you will never regret the time you will have to spend just for learning the basics of a Unix/Linux system...

Raphaël

···

________________________________
De : Germán Molina Larrain <[email protected]>
Envoyé : vendredi 13 avril 2018 03:23:11
Objet : Re: [Radiance-general] Any method to calculate sky view factor in Radiance?

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 (<[email protected]<mailto:[email protected]>>) escribió:
Dear Raphael,

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:[email protected]<mailto:[email protected]>]
Sent: Thursday, April 12, 2018 2:38 PM
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:

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:

cat points | rtrace -h -ab 1 -I scene.oct | rcalc -e 'SVF=\$1;\$1=SVF;'

Raphaël

________________________________
De : Katsuya Obara <[email protected]<mailto:[email protected]>> Envoyé : jeudi 12 avril 2018 01:54:46 À : [email protected]<mailto:[email protected]>
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

____________________________________________________________
Electronic mail messages entering and leaving Arup business systems are scanned for viruses and acceptability of content

_______________________________________________
[email protected]<mailto:[email protected]>

You can use windows power shell to execute Unix command.

Or you can revised the unix command as following:
type points | rtrace -h -ab 1 -I uni.oct | rcalc -e 'SVF=\$1;\$1=SVF;'

···

------------------
Yongqing Zhao
Changsha Green Building & Energy Saving Technology CO.,LTD
Telephone:13574805636
Email:[email protected]
[email protected]

------------------ 原始邮件 ------------------

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 (<[email protected]>) escribió:

Dear Raphael,

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:[email protected]]
Sent: Thursday, April 12, 2018 2:38 PM
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:

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:

cat points | rtrace -h -ab 1 -I scene.oct | rcalc -e 'SVF=\$1;\$1=SVF;'

Raphaël

________________________________
De : Katsuya Obara <[email protected]> Envoyé : jeudi 12 avril 2018 01:54:46 À : [email protected]
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

____________________________________________________________
Electronic mail messages entering and leaving Arup business systems are scanned for viruses and acceptability of content

_______________________________________________