Dear all,
I have a problem on finding the direct horizontal illuminance (DHI) following the steps provided by Dr. Phillip Greenup (Page 253 @ goo.gl/Bw68WQ)
I am able to find the horizontal global illuminance using "rillum.exe". However, I am not able to find out the direct horizontal illuminance. It said:
warning - no light sources found
0
It should not be zero. How can I solve this problem? Hope you guys can help.
FYI, this is my sky.rad.
void brightfunc skyfunc
2 skybright ssldlum.cal
0
10 177 30.2 4 -0.7 0 -1 0 -0.675211 -0.729544 -0.108883
skyfunc glow ground_glow
0
0
4
1 .8 .5 0
ground_glow source ground
0
0
4
0 0 -1 180
skyfunc glow sky_glow
0
0
4 .991 .991 1.101 0
sky_glow source sky
0
0
4 0 0 1 180
Best regards,
Dennis Tsang
You probably have to adjust option -ab when you call rillum (by default -ab 0 is assumed I think)
For instance rillum -ab 1 should be OK
···
________________________________
De : TSANG Kai Kwong <[email protected]>
Envoyé : jeudi 21 décembre 2017 10:28:46
À : [email protected]
Objet : [Radiance-general] Direct horizontal illuminance
Dear all,
I have a problem on finding the direct horizontal illuminance (DHI) following the steps provided by Dr. Phillip Greenup (Page 253 @ goo.gl/Bw68WQ)
I am able to find the horizontal global illuminance using "rillum.exe". However, I am not able to find out the direct horizontal illuminance. It said:
warning - no light sources found
0
It should not be zero. How can I solve this problem? Hope you guys can help.
FYI, this is my sky.rad.
void brightfunc skyfunc
2 skybright ssldlum.cal
0
10 177 30.2 4 -0.7 0 -1 0 -0.675211 -0.729544 -0.108883
skyfunc glow ground_glow
0
0
4
1 .8 .5 0
ground_glow source ground
0
0
4
0 0 -1 180
skyfunc glow sky_glow
0
0
4 .991 .991 1.101 0
sky_glow source sky
0
0
4 0 0 1 180
Best regards,
Dennis Tsang
Dear Compagnon,
Thank you for your reply.
I have tried to use "-ab 0" for the rillum programme. However, it still gives me 0 for the result.
Best regards,
Dennis Tsang
Hello Denis,
You need to use an AB greater than zero for the Glow materials to be
considered
Best!
···
On Thu, 21 Dec 2017 at 9:07 AM, TSANG Kai Kwong < [email protected]> wrote:
Dear Compagnon,
Thank you for your reply.
I have tried to use "-ab 0" for the rillum programme. However, it still
gives me 0 for the result.
Best regards,
Dennis Tsang
_______________________________________________
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https://www.radiance-online.org/mailman/listinfo/radiance-general
Hi Dennis,
Direct horizontal illuminance relates to illumination direct from the sun, not from the rest of the sky. To get a non-zero direct horizontal illuminance, you need to have a sun in your model. The sky description you provided included the sky, but no sun. Is your sun defined separately to sky.rad?
Regards,
Phil.
Dr Phillip Greenup
Senior Designer | Lighting
Arup
Level 17 1 Nicholson Street East Melbourne Vic 3001
d: +61 3 9668 5669
www.arup.com <http://www.arup.com/>
Connect with me on LinkedIn<https://www.linkedin.com/profile/view?id=21592292&trk=hp-identity-name>
[cid:[email protected]]<https://www.arup.com/publications/promotional-materials/section/lighting-design>
···
From: TSANG Kai Kwong [mailto:[email protected]]
Sent: Thursday, 21 December 2017 8:29 PM
To: [email protected]
Subject: [Radiance-general] Direct horizontal illuminance
Dear all,
I have a problem on finding the direct horizontal illuminance (DHI) following the steps provided by Dr. Phillip Greenup (Page 253 @ goo.gl/Bw68WQ)
I am able to find the horizontal global illuminance using "rillum.exe". However, I am not able to find out the direct horizontal illuminance. It said:
warning - no light sources found
0
It should not be zero. How can I solve this problem? Hope you guys can help.
FYI, this is my sky.rad.
void brightfunc skyfunc
2 skybright ssldlum.cal
0
10 177 30.2 4 -0.7 0 -1 0 -0.675211 -0.729544 -0.108883
skyfunc glow ground_glow
0
0
4
1 .8 .5 0
ground_glow source ground
0
0
4
0 0 -1 180
skyfunc glow sky_glow
0
0
4 .991 .991 1.101 0
sky_glow source sky
0
0
4 0 0 1 180
Best regards,
Dennis Tsang
____________________________________________________________
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systems are scanned for viruses and acceptability of content
Dear Dr. Greenup,
Thank you for your help.
I have tried to insert the sun in the sky.rad. However, I am not able to convert the .rad into .oct using "oconv.exe" because of "undefined modifier "solar"".
Here is my sky.rad:
solar source sun
0
0
4 -0.875487 0.087344 -0.475282 0.5
void brightfunc skyfunc
2 skybright ssldlum.cal
0
10 177 30.2 4 -0.7 0 -1 0 -0.675211 -0.729544 -0.108883
skyfunc glow ground_glow
0
0
4
1 .8 .5 0
ground_glow source ground
0
0
4
0 0 -1 180
skyfunc glow sky_glow
0
0
4 .991 .991 1.101 0
sky_glow source sky
0
0
4 0 0 1 180
Best regards,
Dennis Tsang
Dear Dennis,
You will need to define the light entity 'solar' before applying it to the 'sun'. The definition you have provided for 'sun' tells Radiance the direction toward the sun and it's angular size, but it doesn't tell it how bright it is.
An example of the type of definition you require is:
void light solar
0
0
3 1000 1000 1000
This would create a sun with radiance 1000 W/m2/sr in each of the red, green and blue colour bands. Note that I have used 1000 as an example; a normal sun brightness would be more than 1e6 W/m2/sr.
If you want to achieve a known direct horizontal illuminance, you can scale these numbers to suit your target value.
I hope this helps,
Phil.
···
From: TSANG Kai Kwong [mailto:[email protected]]
Sent: Friday, 22 December 2017 3:25 PM
To: [email protected]
Subject: Re: [Radiance-general] Direct horizontal illuminance
Dear Dr. Greenup,
Thank you for your help.
I have tried to insert the sun in the sky.rad. However, I am not able to convert the .rad into .oct using "oconv.exe" because of "undefined modifier "solar"".
Here is my sky.rad:
solar source sun
0
0
4 -0.875487 0.087344 -0.475282 0.5
void brightfunc skyfunc
2 skybright ssldlum.cal
0
10 177 30.2 4 -0.7 0 -1 0 -0.675211 -0.729544 -0.108883
skyfunc glow ground_glow
0
0
4
1 .8 .5 0
ground_glow source ground
0
0
4
0 0 -1 180
skyfunc glow sky_glow
0
0
4 .991 .991 1.101 0
sky_glow source sky
0
0
4 0 0 1 180
Best regards,
Dennis Tsang
____________________________________________________________
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systems are scanned for viruses and acceptability of content
Dear Dr. Greenup,
I am a bit confused by the steps.
In step 3, the horizontal global illuminance is needed to calculate the ground reflectivity. So, should I go to the step 11 to get the HGI? However, if I want to complete the step 11, a completed sky.rad is required, so I have to assume some numbers (solar brightness, ground brightness and arbitrary zenith radiance) in the sky.rad?
How should I assume those numbers? Thank you.
Best regards,
Dennis Tsang
Hi Dennis,
Have you started with the output from the command gensky or gendaylit? I see they are both mentioned in step 2 of the tutorial you referred to, and probably would have given you an output with sun that you would have started with. These are standard Radiance commands for generating sun and sky brightness functions for particular parameters (latitude, longitude, cloud cover, time, etc.). Gensky creates closer to standard CIE sky definitions, while gendaylit can create skies more tailored to measured weather conditions. The manual page for either command might help:
-Chris
···
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