HDR Sky Camera @ LBNL's Flexlab

Andrew_McNeil2 · June 26, 2014, 11:48pm

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site:
http://flexskycam.lbl.gov. I've uploaded sample data, including hdr images
and csv datafiles, recorded by the camera for three days over the past
week( clear, partly cloudy and overcast). We're happy to share more data
with other researchers and daylight practitioners (but we don't have much
to offer yet).

The images can be mapped to a Radiance sky for simulation under real sky
conditions. I have not used the sky HDR images yet, myself, so if anybody
uses them successfully please report back and share what you've done!

Questions about the camera hardware and capabilities should be directed to
Chris Humann at Terrestrial Light.

Best,
Andy

Joe_Smith · June 27, 2014, 4:59am

Hi, Andy, thanks for sharing LBNL's sky mapping experiment!

Can you kindly advice on resources that elaborate on how to use HDR sky
image for daylight simulation? Does it involve specifying the HDR image,
rather than a "skyfunc", as the material identifier for the sky geometry?
How is the pixel value of a given point on the HDR image converted to
luminance value of the corresponding position on the sky?

Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov>于2014年6月27日星期五写道：

···

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site:
http://flexskycam.lbl.gov. I've uploaded sample data, including hdr
images and csv datafiles, recorded by the camera for three days over the
past week( clear, partly cloudy and overcast). We're happy to share more
data with other researchers and daylight practitioners (but we don't have
much to offer yet).

The images can be mapped to a Radiance sky for simulation under real sky
conditions. I have not used the sky HDR images yet, myself, so if anybody
uses them successfully please report back and share what you've done!

Questions about the camera hardware and capabilities should be directed to
Chris Humann at Terrestrial Light.

Best,
Andy

CHI-German_Molina · June 27, 2014, 9:38pm

Wow, I have been thinking on doing this for a while... although I have no
idea where to start from.

Is it possible to calculate the Daylight Coefficients of the building; and
use the HDR image to generate sky vectors and calculate different options
for optimizing daylighting?

I am picturing a computer that, every 5 minutes, calculate the sky vector,
computes the interior lighting conditions, and simulates the different
lighting options performing a whole-building lighting control with no photo
sensors. Even more, maybe a whole neighborhood could use the same camera.
Nonsense?

Thanks for sharing!

···

2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker@gmail.com>:

Hi, Andy, thanks for sharing LBNL's sky mapping experiment!

Can you kindly advice on resources that elaborate on how to use HDR sky
image for daylight simulation? Does it involve specifying the HDR image,
rather than a "skyfunc", as the material identifier for the sky geometry?
How is the pixel value of a given point on the HDR image converted to
luminance value of the corresponding position on the sky?

Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov>于2014年6月27日星期五写道：

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site:
http://flexskycam.lbl.gov. I've uploaded sample data, including hdr
images and csv datafiles, recorded by the camera for three days over the
past week( clear, partly cloudy and overcast). We're happy to share more
data with other researchers and daylight practitioners (but we don't have
much to offer yet).

The images can be mapped to a Radiance sky for simulation under real sky
conditions. I have not used the sky HDR images yet, myself, so if anybody
uses them successfully please report back and share what you've done!

Questions about the camera hardware and capabilities should be directed
to Chris Humann at Terrestrial Light.

Best,
Andy

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
*Germán Molina L.*
Ingeniero Trainee
Hunter Douglas Chile S.A.
Celular +569 89224445

--

*Nota de Confidencialidad:* Este mensaje incluído los archivos adjuntos son
confidenciales y pueden contener informacion privilegiada protegida por
ley. Si Ud. no es el destinatario, deberia abstenerse de copiarlo,
distribuirlo, divulgarlo o usar la informacion contenida. Por favor, avise
inmediatamente al emisor y borre este mensaje de su sistema. Los mensajes
electronicos son susceptibles de ser cambiados, infectados o adulterados
sin autorizacion. No asumimos responsabilidad alguna por ninguna clase de
cambios o sus consecuencias. Usted debe estar informado que la compania
puede hacer un seguimiento de sus mensajes electronicos y su contenido,
gracias.

*Confidentiality Notice:* The information contained in this email message,
including any attachment, is confidential and is intended only for the
person or entity to which it is addressed. If you are neither the intended
recipient nor the employee or agent responsible for delivering this message
to the intended recipient, you are hereby notified that you may not review,
retransmit, convert to hard copy, copy, use or distribute this email
message or any attachments to it. If you have received this email in error,
please contact the sender immediately and delete this message from any
computer or other data bank, Thank you.

A informação transmitida é confidencial e para conhecimento exclusivo do
destinatário. Sua utilização, não autorizada, constitui crime passível de
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Rob_Guglielmetti · June 27, 2014, 9:58pm

Hi German, and everyone else. Certainly one could use these HDR images to
generate sky vectors and apply them to daylight coefficients for a given
model(s). Greg Ward has created a cool tool called mksource to facilitate
this process in Radiance, identifying small, intense pixels in the image;
creating and placing Radiance light sources in their stead, and zeroing the
pixels to avoid double counting.

Considerations:
- Capturing the true (full) dynamic range of an exterior scene with direct
sun is difficult.
- Using locally-captured HDR images for daylight availability analysis is
statistically dubious. Granted, so is using TMY data, for different
reasons. This is why I changed the title of this list to "considerations",
from "problems". =)

···

On Fri, Jun 27, 2014 at 3:38 PM, CHI-German Molina <gmolina@hdlao.com> wrote:

Wow, I have been thinking on doing this for a while... although I have no
idea where to start from.

Is it possible to calculate the Daylight Coefficients of the building; and
use the HDR image to generate sky vectors and calculate different options
for optimizing daylighting?

I am picturing a computer that, every 5 minutes, calculate the sky vector,
computes the interior lighting conditions, and simulates the different
lighting options performing a whole-building lighting control with no photo
sensors. Even more, maybe a whole neighborhood could use the same camera.
Nonsense?

Thanks for sharing!

2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker@gmail.com>:

Hi, Andy, thanks for sharing LBNL's sky mapping experiment!

Can you kindly advice on resources that elaborate on how to use HDR sky
image for daylight simulation? Does it involve specifying the HDR image,
rather than a "skyfunc", as the material identifier for the sky geometry?
How is the pixel value of a given point on the HDR image converted to
luminance value of the corresponding position on the sky?

Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov>于2014年6月27日星期五写道：

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site:
http://flexskycam.lbl.gov. I've uploaded sample data, including hdr
images and csv datafiles, recorded by the camera for three days over the
past week( clear, partly cloudy and overcast). We're happy to share more
data with other researchers and daylight practitioners (but we don't have
much to offer yet).

The images can be mapped to a Radiance sky for simulation under real sky
conditions. I have not used the sky HDR images yet, myself, so if anybody
uses them successfully please report back and share what you've done!

Questions about the camera hardware and capabilities should be directed
to Chris Humann at Terrestrial Light.

Best,
Andy

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
*Germán Molina L.*
Ingeniero Trainee
Hunter Douglas Chile S.A.
Celular +569 89224445

*Nota de Confidencialidad:* Este mensaje incluído los archivos adjuntos
son confidenciales y pueden contener informacion privilegiada protegida por
ley. Si Ud. no es el destinatario, deberia abstenerse de copiarlo,
distribuirlo, divulgarlo o usar la informacion contenida. Por favor, avise
inmediatamente al emisor y borre este mensaje de su sistema. Los mensajes
electronicos son susceptibles de ser cambiados, infectados o adulterados
sin autorizacion. No asumimos responsabilidad alguna por ninguna clase de
cambios o sus consecuencias. Usted debe estar informado que la compania
puede hacer un seguimiento de sus mensajes electronicos y su contenido,
gracias.

*Confidentiality Notice:* The information contained in this email
message, including any attachment, is confidential and is intended only for
the person or entity to which it is addressed. If you are neither the
intended recipient nor the employee or agent responsible for delivering
this message to the intended recipient, you are hereby notified that you
may not review, retransmit, convert to hard copy, copy, use or distribute
this email message or any attachments to it. If you have received this
email in error, please contact the sender immediately and delete this
message from any computer or other data bank, Thank you.

A informação transmitida é confidencial e para conhecimento exclusivo do
destinatário. Sua utilização, não autorizada, constitui crime passível de
prisão. Todas as precauções possíveis foram tomadas para garantir que este
e-mail não contenha vírus. Uma vez que nossa empresa não pode assumir
responsabilidade por nenhuma perda ou dano causado por este e-mail ou de
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antivírus antes de qualquer uso.

_______________________________________________
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http://www.radiance-online.org/mailman/listinfo/radiance-general

Andrew_McNeil2 · June 27, 2014, 11:28pm

Hi All,

I haven't done any testing myself, I wanted to make the data available
right away so that others could tinker too (and maybe make it easier for
me).

Joe - You're correct that the HDR sky image essentially replaces the
skyfunc modifier, here's a thread where Kyle was doing the same thing:
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008962.html

Rob - In a clear sky condition our HDR images won't capture the full
luminance of the sun. Mksource would be helpful to zero out the pixels, but
the source that it makes won't be useful without adjusting the radiance of
the source to match that of the sun.

Best,
Andy

···

On Fri, Jun 27, 2014 at 2:58 PM, Rob Guglielmetti < rob.guglielmetti@gmail.com> wrote:

Hi German, and everyone else. Certainly one could use these HDR images to
generate sky vectors and apply them to daylight coefficients for a given
model(s). Greg Ward has created a cool tool called mksource to facilitate
this process in Radiance, identifying small, intense pixels in the image;
creating and placing Radiance light sources in their stead, and zeroing the
pixels to avoid double counting.

Considerations:
- Capturing the true (full) dynamic range of an exterior scene with direct
sun is difficult.
- Using locally-captured HDR images for daylight availability analysis is
statistically dubious. Granted, so is using TMY data, for different
reasons. This is why I changed the title of this list to "considerations",
from "problems". =)

On Fri, Jun 27, 2014 at 3:38 PM, CHI-German Molina <gmolina@hdlao.com> > wrote:

Wow, I have been thinking on doing this for a while... although I have no
idea where to start from.

Is it possible to calculate the Daylight Coefficients of the building;
and use the HDR image to generate sky vectors and calculate different
options for optimizing daylighting?

I am picturing a computer that, every 5 minutes, calculate the sky
vector, computes the interior lighting conditions, and simulates the
different lighting options performing a whole-building lighting control
with no photo sensors. Even more, maybe a whole neighborhood could use the
same camera. Nonsense?

Thanks for sharing!

2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker@gmail.com>:

Hi, Andy, thanks for sharing LBNL's sky mapping experiment!

Can you kindly advice on resources that elaborate on how to use HDR sky
image for daylight simulation? Does it involve specifying the HDR image,
rather than a "skyfunc", as the material identifier for the sky geometry?
How is the pixel value of a given point on the HDR image converted to
luminance value of the corresponding position on the sky?

Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov>于2014年6月27日星期五写道：

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site:
http://flexskycam.lbl.gov. I've uploaded sample data, including hdr
images and csv datafiles, recorded by the camera for three days over the
past week( clear, partly cloudy and overcast). We're happy to share more
data with other researchers and daylight practitioners (but we don't have
much to offer yet).

The images can be mapped to a Radiance sky for simulation under real
sky conditions. I have not used the sky HDR images yet, myself, so if
anybody uses them successfully please report back and share what you've
done!

Questions about the camera hardware and capabilities should be directed
to Chris Humann at Terrestrial Light.

Best,
Andy

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
*Germán Molina L.*
Ingeniero Trainee
Hunter Douglas Chile S.A.
Celular +569 89224445

*Nota de Confidencialidad:* Este mensaje incluído los archivos adjuntos
son confidenciales y pueden contener informacion privilegiada protegida por
ley. Si Ud. no es el destinatario, deberia abstenerse de copiarlo,
distribuirlo, divulgarlo o usar la informacion contenida. Por favor, avise
inmediatamente al emisor y borre este mensaje de su sistema. Los mensajes
electronicos son susceptibles de ser cambiados, infectados o adulterados
sin autorizacion. No asumimos responsabilidad alguna por ninguna clase de
cambios o sus consecuencias. Usted debe estar informado que la compania
puede hacer un seguimiento de sus mensajes electronicos y su contenido,
gracias.

*Confidentiality Notice:* The information contained in this email
message, including any attachment, is confidential and is intended only for
the person or entity to which it is addressed. If you are neither the
intended recipient nor the employee or agent responsible for delivering
this message to the intended recipient, you are hereby notified that you
may not review, retransmit, convert to hard copy, copy, use or distribute
this email message or any attachments to it. If you have received this
email in error, please contact the sender immediately and delete this
message from any computer or other data bank, Thank you.

A informação transmitida é confidencial e para conhecimento exclusivo do
destinatário. Sua utilização, não autorizada, constitui crime passível de
prisão. Todas as precauções possíveis foram tomadas para garantir que este
e-mail não contenha vírus. Uma vez que nossa empresa não pode assumir
responsabilidade por nenhuma perda ou dano causado por este e-mail ou de
seus anexos, recomendamos que o destinatário utilize seus procedimentos de
antivírus antes de qualquer uso.

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
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Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

Greg_Ward · June 28, 2014, 8:56am

I think that a reasonable approach is to use the global illuminance reading to determine the direct + indirect integrated total, then compare this to the integration of the HDR sky dome recording. You can then add in a solar source whose solid angle is enlarged to cover the "clipped" pixels in the HDR image, adjusting its radiance such that the new total:

integrated_masked_HDR + solar_source*adj_solid_angle*cos_theta = measured_illuminance

The larger sun that includes circumsolar will lead to slightly enlarged penumbras in some cases, but it's a reasonable compromise. I'm sure a script could be made to automate the above process without too much effort.

Cheers,
-Greg

···

From: Andrew McNeil <amcneil@lbl.gov>
Subject: Re: [Radiance-general] HDR Sky Camera @ LBNL's Flexlab
Date: June 28, 2014 1:28:09 AM GMT+02:00

Hi All,

I haven't done any testing myself, I wanted to make the data available right away so that others could tinker too (and maybe make it easier for me).

Joe - You're correct that the HDR sky image essentially replaces the skyfunc modifier, here's a thread where Kyle was doing the same thing: http://www.radiance-online.org/pipermail/radiance-general/2012-October/008962.html

Rob - In a clear sky condition our HDR images won't capture the full luminance of the sun. Mksource would be helpful to zero out the pixels, but the source that it makes won't be useful without adjusting the radiance of the source to match that of the sun.

Best,
Andy

On Fri, Jun 27, 2014 at 2:58 PM, Rob Guglielmetti <rob.guglielmetti@gmail.com> wrote:
Hi German, and everyone else. Certainly one could use these HDR images to generate sky vectors and apply them to daylight coefficients for a given model(s). Greg Ward has created a cool tool called mksource to facilitate this process in Radiance, identifying small, intense pixels in the image; creating and placing Radiance light sources in their stead, and zeroing the pixels to avoid double counting.

Considerations:
- Capturing the true (full) dynamic range of an exterior scene with direct sun is difficult.
- Using locally-captured HDR images for daylight availability analysis is statistically dubious. Granted, so is using TMY data, for different reasons. This is why I changed the title of this list to "considerations", from "problems". =)

On Fri, Jun 27, 2014 at 3:38 PM, CHI-German Molina <gmolina@hdlao.com> wrote:
Wow, I have been thinking on doing this for a while... although I have no idea where to start from.

Is it possible to calculate the Daylight Coefficients of the building; and use the HDR image to generate sky vectors and calculate different options for optimizing daylighting?

I am picturing a computer that, every 5 minutes, calculate the sky vector, computes the interior lighting conditions, and simulates the different lighting options performing a whole-building lighting control with no photo sensors. Even more, maybe a whole neighborhood could use the same camera. Nonsense?

Thanks for sharing!

2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker@gmail.com>:
Hi, Andy, thanks for sharing LBNL's sky mapping experiment!

Can you kindly advice on resources that elaborate on how to use HDR sky image for daylight simulation? Does it involve specifying the HDR image, rather than a "skyfunc", as the material identifier for the sky geometry? How is the pixel value of a given point on the HDR image converted to luminance value of the corresponding position on the sky?

Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov>于2014年6月27日星期五写道：

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site: http://flexskycam.lbl.gov. I've uploaded sample data, including hdr images and csv datafiles, recorded by the camera for three days over the past week( clear, partly cloudy and overcast). We're happy to share more data with other researchers and daylight practitioners (but we don't have much to offer yet).

The images can be mapped to a Radiance sky for simulation under real sky conditions. I have not used the sky HDR images yet, myself, so if anybody uses them successfully please report back and share what you've done!

Questions about the camera hardware and capabilities should be directed to Chris Humann at Terrestrial Light.

Best,
Andy

John_Mardaljevic · June 28, 2014, 11:07am

Hi Greg,

The larger sun that includes circumsolar will lead to slightly enlarged penumbras in some cases, but it's a reasonable compromise.

I thought that (with default settings) a single ray is used to sample a "light" source solid angle, resulting in no solar penumbra. Has this changed and/or am I misunderstanding this?

Cheers

John

John Mardaljevic PhD FSLL
Professor of Building Daylight Modelling
School of Civil & Building Engineering
Loughborough University
Loughborough
Leicestershire
LE11 3TU, UK

Tel: +44 1509 222630 (Direct)
Tel: +44 1509 228529 (Pam Allen, secretary)

j.mardaljevic@lboro.ac.uk<mailto:j.mardaljevic@lboro.ac.uk>

http://www.lboro.ac.uk/departments/civil-building/staff/mardaljevicjohn/<http://www.lboro.ac.uk/departments/civil-building/staff/mardaljevicjohn>

Personal daylighting website:
http://climate-based-daylighting.com

Greg_Ward · June 28, 2014, 11:18am

Yes, you're right. It's only if you use the PENUMBRAS=True in rad or set -dj > 0 that you'll actually see the penumbras from light sources, including the sun.

Cheers,
-Greg

···

From: John Mardaljevic <J.Mardaljevic@lboro.ac.uk>
Subject: Re: [Radiance-general] HDR Sky Camera @ LBNL's Flexlab
Date: June 28, 2014 1:07:19 PM GMT+02:00

Hi Greg,

> The larger sun that includes circumsolar will lead to slightly enlarged penumbras in some cases, but it's a reasonable compromise.

I thought that (with default settings) a single ray is used to sample a "light" source solid angle, resulting in no solar penumbra. Has this changed and/or am I misunderstanding this?

Cheers

John

Joe_Smith · June 28, 2014, 5:06pm

Hi, I found 2 references and did a test to generate HDR image-based
rendering, steps are explained below.

But I'm still rubbing my head to understand how the Cartesian coordinates
or the postion vector of a point on the sky is transformed as UV
coordinates of the fisheye image as shown in the "angmap.cal" file. So,
advices are greatly appreciated!

Thanks!
Joe

References:
1. Debevec, P. (2002). Image-based lighting. IEEE Computer Graphics and
Applications, 22(2), 26-34. doi: 10.1109/38.988744
2. Au, P. Y. P. (2013). HDR Luminance Measurement: Comparing real and
simulated data. (Master of Building Science Thesis), Victoria University of
Wellington.

Steps:
Step1. prepare the following 6 files and put them in the same folder

#### 1.1 geom.rad ################################################
red_plastic sphere ball
0
0
4 2 2 0.5 0.5

steel sphere ball1
0
0
4 2 -2 0.5 0.5

gold sphere ball2
0
0
4 -2 -2 0.5 0.5

white_matte sphere ball3
0
0
4 -2 2 0.5 0.5

crystal sphere ball4
0
0
4 0 0 1 1

!genbox gray_plastic pedestal_top 8 8 0.5 | xform -t -4 -4 -0.5

#### 1.2 materials.mat ################################################
void plastic red_plastic
0
0
5 .7 .1 .1 .06 .1

void metal steel
0
0
5 0.6 0.62 0.68 1 0

void metal gold
0
0
5 0.75 0.55 0.25 0.85 0.2

void plastic white_matte
0
0
5 .8 .8 .8 0 0

void dielectric crystal
0
0
5 .5 .5 .5 1.5 0

void plastic black_matte
0
0
5 .02 .02 .02 .00 .00

void plastic gray_plastic
0
0
5 0.25 0.25 0.25 0.06 0.0

#### 1.3 sky_and_ground.rad ################################################
void colorpict hdr_image
7 red green blue 140621_1530.hdr angmap.cal u v
0
0

hdr_image glow sky_glow
0
0
4 1 1 1 0

sky_glow source HDR_sky
0
0
4 0 0 1 180

# ground
void glow ground_glow
0
0
4 1 1 1 0

ground_glow source ground
0
0
4 0 0 -1 180

#### 1.4 angmap.cal ################################################
{
angmap.cal

Convert from directions in the world (Dx, Dy, Dz) into (u,v)
coordinates on the light probe image

+z is up (toward top of sphere, i.e. the zenith)
+y is North
}

d = sqrt(Dx*Dx + Dy*Dy);

r = acos(Dz)/PI;

u = 0.5 - Dx/d * r;
v = 0.5 + Dy/d * r;

#### 1.5 view.vf ################################################
# looking towards east
#rvu -vtv -vp -12 0 0.5 -vd 1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards west
#rvu -vtv -vp 12 0 0.5 -vd -1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards north
rvu -vtv -vp 0 -12 0.5 -vd 0 1 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards south
#rvu -vtv -vp 0 12 0.5 -vd 0 -1 0 -vu 0 0 1 -vh 60 -vv 40

#### 1.6 cmd.sh ################################################
oconv ./materials.mat ./sky_and_ground.rad ./geom.rad > ./scene.oct

rvu -vf ./view.vf ./scene.oct

#ximage ./sky.hdr

rpict -x 2400 -y 2400 -t 30 -ab 1 -ar 50000 -aa 0.08 -ad 128 -as 64 -st 0
-lw 0 -lr 8 -vf ./view.vf ./scene.oct > ./image.hdr

pfilt -1 -x /3 -y /3 -r 1 ./image.hdr > ./image_filtered.hdr

Step2. put the 140621_1530.hdr file provided by LBNL (
http://flexskycam.lbl.gov) in the same folder

Step3. run the cmd.sh batch file to produce the rendering

···

On Sat, Jun 28, 2014 at 7:28 AM, Andrew McNeil <amcneil@lbl.gov> wrote:

Hi All,

I haven't done any testing myself, I wanted to make the data available
right away so that others could tinker too (and maybe make it easier for
me).

Joe - You're correct that the HDR sky image essentially replaces the
skyfunc modifier, here's a thread where Kyle was doing the same thing:
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008962.html

Rob - In a clear sky condition our HDR images won't capture the full
luminance of the sun. Mksource would be helpful to zero out the pixels, but
the source that it makes won't be useful without adjusting the radiance of
the source to match that of the sun.

Best,
Andy

On Fri, Jun 27, 2014 at 2:58 PM, Rob Guglielmetti < > rob.guglielmetti@gmail.com> wrote:

Hi German, and everyone else. Certainly one could use these HDR images to
generate sky vectors and apply them to daylight coefficients for a given
model(s). Greg Ward has created a cool tool called mksource to facilitate
this process in Radiance, identifying small, intense pixels in the image;
creating and placing Radiance light sources in their stead, and zeroing the
pixels to avoid double counting.

Considerations:
- Capturing the true (full) dynamic range of an exterior scene with
direct sun is difficult.
- Using locally-captured HDR images for daylight availability analysis is
statistically dubious. Granted, so is using TMY data, for different
reasons. This is why I changed the title of this list to "considerations",
from "problems". =)

On Fri, Jun 27, 2014 at 3:38 PM, CHI-German Molina <gmolina@hdlao.com> >> wrote:

Wow, I have been thinking on doing this for a while... although I have
no idea where to start from.

Is it possible to calculate the Daylight Coefficients of the building;
and use the HDR image to generate sky vectors and calculate different
options for optimizing daylighting?

I am picturing a computer that, every 5 minutes, calculate the sky
vector, computes the interior lighting conditions, and simulates the
different lighting options performing a whole-building lighting control
with no photo sensors. Even more, maybe a whole neighborhood could use the
same camera. Nonsense?

Thanks for sharing!

2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker@gmail.com>:

Hi, Andy, thanks for sharing LBNL's sky mapping experiment!

Can you kindly advice on resources that elaborate on how to use HDR sky
image for daylight simulation? Does it involve specifying the HDR image,
rather than a "skyfunc", as the material identifier for the sky geometry?
How is the pixel value of a given point on the HDR image converted to
luminance value of the corresponding position on the sky?

Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov>于2014年6月27日星期五写道：

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site:
http://flexskycam.lbl.gov. I've uploaded sample data, including hdr
images and csv datafiles, recorded by the camera for three days over the
past week( clear, partly cloudy and overcast). We're happy to share more
data with other researchers and daylight practitioners (but we don't have
much to offer yet).

The images can be mapped to a Radiance sky for simulation under real
sky conditions. I have not used the sky HDR images yet, myself, so if
anybody uses them successfully please report back and share what you've
done!

Questions about the camera hardware and capabilities should be
directed to Chris Humann at Terrestrial Light.

Best,
Andy

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
*Germán Molina L.*
Ingeniero Trainee
Hunter Douglas Chile S.A.
Celular +569 89224445

*Nota de Confidencialidad:* Este mensaje incluído los archivos adjuntos
son confidenciales y pueden contener informacion privilegiada protegida por
ley. Si Ud. no es el destinatario, deberia abstenerse de copiarlo,
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gracias.

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Santiago_Torres · June 30, 2014, 4:05am

Hi German,

There is some interesting work on simulation based controls for daylighting from the TU Wien. See here:
http://www.ibpsa.org/proceedings/BS2005/BS05_0693_700.pdf
http://www.ibpsa.org/proceedings/BS2005/BS05_1163_1170.pdf

Santiago

···

From: CHI-German Molina [mailto:gmolina@hdlao.com]
Sent: 2014年6月28日 5:38
To: Radiance general discussion
Subject: Re: [Radiance-general] HDR Sky Camera @ LBNL's Flexlab

Wow, I have been thinking on doing this for a while... although I have no idea where to start from.

Is it possible to calculate the Daylight Coefficients of the building; and use the HDR image to generate sky vectors and calculate different options for optimizing daylighting?

I am picturing a computer that, every 5 minutes, calculate the sky vector, computes the interior lighting conditions, and simulates the different lighting options performing a whole-building lighting control with no photo sensors. Even more, maybe a whole neighborhood could use the same camera. Nonsense?

Thanks for sharing!

2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker@gmail.com<mailto:the.oat.cracker@gmail.com>>:
Hi, Andy, thanks for sharing LBNL's sky mapping experiment!

Can you kindly advice on resources that elaborate on how to use HDR sky image for daylight simulation? Does it involve specifying the HDR image, rather than a "skyfunc", as the material identifier for the sky geometry? How is the pixel value of a given point on the HDR image converted to luminance value of the corresponding position on the sky?

Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov<mailto:amcneil@lbl.gov>>于2014年6月27日星期五写道：

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site: http://flexskycam.lbl.gov. I've uploaded sample data, including hdr images and csv datafiles, recorded by the camera for three days over the past week( clear, partly cloudy and overcast). We're happy to share more data with other researchers and daylight practitioners (but we don't have much to offer yet).

The images can be mapped to a Radiance sky for simulation under real sky conditions. I have not used the sky HDR images yet, myself, so if anybody uses them successfully please report back and share what you've done!

Questions about the camera hardware and capabilities should be directed to Chris Humann at Terrestrial Light.

Best,
Andy

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org<mailto:Radiance-general@radiance-online.org>
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
Germán Molina L.
Ingeniero Trainee
Hunter Douglas Chile S.A.
Celular +569 89224445

Nota de Confidencialidad: Este mensaje incluído los archivos adjuntos son confidenciales y pueden contener informacion privilegiada protegida por ley. Si Ud. no es el destinatario, deberia abstenerse de copiarlo, distribuirlo, divulgarlo o usar la informacion contenida. Por favor, avise inmediatamente al emisor y borre este mensaje de su sistema. Los mensajes electronicos son susceptibles de ser cambiados, infectados o adulterados sin autorizacion. No asumimos responsabilidad alguna por ninguna clase de cambios o sus consecuencias. Usted debe estar informado que la compania puede hacer un seguimiento de sus mensajes electronicos y su contenido, gracias.

Confidentiality Notice: The information contained in this email message, including any attachment, is confidential and is intended only for the person or entity to which it is addressed. If you are neither the intended recipient nor the employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that you may not review, retransmit, convert to hard copy, copy, use or distribute this email message or any attachments to it. If you have received this email in error, please contact the sender immediately and delete this message from any computer or other data bank, Thank you.

A informação transmitida é confidencial e para conhecimento exclusivo do destinatário. Sua utilização, não autorizada, constitui crime passível de prisão. Todas as precauções possíveis foram tomadas para garantir que este e-mail não contenha vírus. Uma vez que nossa empresa não pode assumir responsabilidade por nenhuma perda ou dano causado por este e-mail ou de seus anexos, recomendamos que o destinatário utilize seus procedimentos de antivírus antes de qualquer uso.
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Christian_Humann · June 30, 2014, 7:06pm

Hi Joe,

The global values in the CSV file are in footcandles so you will need to multiply them by 10.76 in order to get Lux.

Also, you'll need to add a source description for the sun in order to get the solar contribution as the camera sensor can not capture the intensity of the sun for the HDR image. Essentially the HDR image allows you to get a close approximation of the global diffuse value. I use gendaylit (see below) to generate the sun and sky scene. You can get the altitude, azimuth, direct-normal-illuminance and diffuse-horizontal-illuminance from the CSV file (be sure to multiply the latter two values by 10.76 to translate them from footcandles to Lux for input into Gendaylit). Also be sure to adjust your 'rtrace' results by dividing by 10.76 to get footcandles if you want to compare to the global-horizontal-illuminacne readings in the CSV file.

########Sun and Sky scene -----> global.rad
!gendaylit -ang 45.41 85.92 -w -O 0 -L 80463.28 19916.76 | xform -e -rz 0
void colorpict skypict
11 red green blue 140621_1530.hdr fisheye.cal fish_u fish_v -rx 90 -rz 180
0
0

skypict glow skyglow
0
0
4 1 1 1 1

skyglow source sky
0
0
4 0 0 1 180

skypict glow groundglow
0
0
4 1 1 1 0

groundglow source ground
0
0
4 0 0 -1 180

···

#########
# 3. the cmd.sh file
oconv ./global.rad > ./scene_empty.oct

echo '0 0 0 0 0 1' | rtrace -I -h -w -ab 1 -oov ./scene_empty.oct > ./results_position_irradiance_RGB_wm2.txt

cat ./results_position_irradiance_RGB_wm2.txt | rcalc -e '$1=179*(0.265*$4+0.670*$5+0.065*$6)/10.76' > ./results_illuminance_lux.txt
##########

When I run the above I get a global horizontal illuminance value from 'rtrace' of approx. 6900 footcandles. The photometer gave a reading of 7176 footcandles.

I'm still working my brain around all this as well and hope that these discussions will foster a better understanding of how to use the HDR images for the highest level of accuracy possible.

Hope this helps.

Best,
Chris

On Jun 28, 2014, at 10:06 AM, Joe Smith <the.oat.cracker@gmail.com> wrote:

Hi, I found 2 references and did a test to generate HDR image-based rendering, steps are explained below.

But I'm still rubbing my head to understand how the Cartesian coordinates or the postion vector of a point on the sky is transformed as UV coordinates of the fisheye image as shown in the "angmap.cal" file. So, advices are greatly appreciated!

Thanks!
Joe

References:
1. Debevec, P. (2002). Image-based lighting. IEEE Computer Graphics and Applications, 22(2), 26-34. doi: 10.1109/38.988744
2. Au, P. Y. P. (2013). HDR Luminance Measurement: Comparing real and simulated data. (Master of Building Science Thesis), Victoria University of Wellington.

Steps:
Step1. prepare the following 6 files and put them in the same folder

#### 1.1 geom.rad ################################################
red_plastic sphere ball
0
0
4 2 2 0.5 0.5

steel sphere ball1
0
0
4 2 -2 0.5 0.5

gold sphere ball2
0
0
4 -2 -2 0.5 0.5

white_matte sphere ball3
0
0
4 -2 2 0.5 0.5

crystal sphere ball4
0
0
4 0 0 1 1

!genbox gray_plastic pedestal_top 8 8 0.5 | xform -t -4 -4 -0.5

#### 1.2 materials.mat ################################################
void plastic red_plastic
0
0
5 .7 .1 .1 .06 .1

void metal steel
0
0
5 0.6 0.62 0.68 1 0

void metal gold
0
0
5 0.75 0.55 0.25 0.85 0.2

void plastic white_matte
0
0
5 .8 .8 .8 0 0

void dielectric crystal
0
0
5 .5 .5 .5 1.5 0

void plastic black_matte
0
0
5 .02 .02 .02 .00 .00

void plastic gray_plastic
0
0
5 0.25 0.25 0.25 0.06 0.0

#### 1.3 sky_and_ground.rad ################################################
void colorpict hdr_image
7 red green blue 140621_1530.hdr angmap.cal u v
0
0

hdr_image glow sky_glow
0
0
4 1 1 1 0

sky_glow source HDR_sky
0
0
4 0 0 1 180

# ground
void glow ground_glow
0
0
4 1 1 1 0

ground_glow source ground
0
0
4 0 0 -1 180

#### 1.4 angmap.cal ################################################
{
angmap.cal

Convert from directions in the world (Dx, Dy, Dz) into (u,v)
coordinates on the light probe image

+z is up (toward top of sphere, i.e. the zenith)
+y is North
}

d = sqrt(Dx*Dx + Dy*Dy);

r = acos(Dz)/PI;

u = 0.5 - Dx/d * r;
v = 0.5 + Dy/d * r;

#### 1.5 view.vf ################################################
# looking towards east
#rvu -vtv -vp -12 0 0.5 -vd 1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards west
#rvu -vtv -vp 12 0 0.5 -vd -1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards north
rvu -vtv -vp 0 -12 0.5 -vd 0 1 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards south
#rvu -vtv -vp 0 12 0.5 -vd 0 -1 0 -vu 0 0 1 -vh 60 -vv 40

#### 1.6 cmd.sh ################################################
oconv ./materials.mat ./sky_and_ground.rad ./geom.rad > ./scene.oct

rvu -vf ./view.vf ./scene.oct

#ximage ./sky.hdr

rpict -x 2400 -y 2400 -t 30 -ab 1 -ar 50000 -aa 0.08 -ad 128 -as 64 -st 0 -lw 0 -lr 8 -vf ./view.vf ./scene.oct > ./image.hdr

pfilt -1 -x /3 -y /3 -r 1 ./image.hdr > ./image_filtered.hdr

Step2. put the 140621_1530.hdr file provided by LBNL (http://flexskycam.lbl.gov) in the same folder

Step3. run the cmd.sh batch file to produce the rendering

On Sat, Jun 28, 2014 at 7:28 AM, Andrew McNeil <amcneil@lbl.gov> wrote:
Hi All,

I haven't done any testing myself, I wanted to make the data available right away so that others could tinker too (and maybe make it easier for me).

Joe - You're correct that the HDR sky image essentially replaces the skyfunc modifier, here's a thread where Kyle was doing the same thing: http://www.radiance-online.org/pipermail/radiance-general/2012-October/008962.html

Rob - In a clear sky condition our HDR images won't capture the full luminance of the sun. Mksource would be helpful to zero out the pixels, but the source that it makes won't be useful without adjusting the radiance of the source to match that of the sun.

Best,
Andy

On Fri, Jun 27, 2014 at 2:58 PM, Rob Guglielmetti <rob.guglielmetti@gmail.com> wrote:
Hi German, and everyone else. Certainly one could use these HDR images to generate sky vectors and apply them to daylight coefficients for a given model(s). Greg Ward has created a cool tool called mksource to facilitate this process in Radiance, identifying small, intense pixels in the image; creating and placing Radiance light sources in their stead, and zeroing the pixels to avoid double counting.

Considerations:
- Capturing the true (full) dynamic range of an exterior scene with direct sun is difficult.
- Using locally-captured HDR images for daylight availability analysis is statistically dubious. Granted, so is using TMY data, for different reasons. This is why I changed the title of this list to "considerations", from "problems". =)

On Fri, Jun 27, 2014 at 3:38 PM, CHI-German Molina <gmolina@hdlao.com> wrote:
Wow, I have been thinking on doing this for a while... although I have no idea where to start from.

Is it possible to calculate the Daylight Coefficients of the building; and use the HDR image to generate sky vectors and calculate different options for optimizing daylighting?

I am picturing a computer that, every 5 minutes, calculate the sky vector, computes the interior lighting conditions, and simulates the different lighting options performing a whole-building lighting control with no photo sensors. Even more, maybe a whole neighborhood could use the same camera. Nonsense?

Thanks for sharing!

2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker@gmail.com>:
Hi, Andy, thanks for sharing LBNL's sky mapping experiment!

Can you kindly advice on resources that elaborate on how to use HDR sky image for daylight simulation? Does it involve specifying the HDR image, rather than a "skyfunc", as the material identifier for the sky geometry? How is the pixel value of a given point on the HDR image converted to luminance value of the corresponding position on the sky?

Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov>于2014年6月27日星期五写道：

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site: http://flexskycam.lbl.gov. I've uploaded sample data, including hdr images and csv datafiles, recorded by the camera for three days over the past week( clear, partly cloudy and overcast). We're happy to share more data with other researchers and daylight practitioners (but we don't have much to offer yet).

The images can be mapped to a Radiance sky for simulation under real sky conditions. I have not used the sky HDR images yet, myself, so if anybody uses them successfully please report back and share what you've done!

Questions about the camera hardware and capabilities should be directed to Chris Humann at Terrestrial Light.

Best,
Andy

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
Germán Molina L.
Ingeniero Trainee
Hunter Douglas Chile S.A.
Celular +569 89224445

Nota de Confidencialidad: Este mensaje incluído los archivos adjuntos son confidenciales y pueden contener informacion privilegiada protegida por ley. Si Ud. no es el destinatario, deberia abstenerse de copiarlo, distribuirlo, divulgarlo o usar la informacion contenida. Por favor, avise inmediatamente al emisor y borre este mensaje de su sistema. Los mensajes electronicos son susceptibles de ser cambiados, infectados o adulterados sin autorizacion. No asumimos responsabilidad alguna por ninguna clase de cambios o sus consecuencias. Usted debe estar informado que la compania puede hacer un seguimiento de sus mensajes electronicos y su contenido, gracias.

Confidentiality Notice: The information contained in this email message, including any attachment, is confidential and is intended only for the person or entity to which it is addressed. If you are neither the intended recipient nor the employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that you may not review, retransmit, convert to hard copy, copy, use or distribute this email message or any attachments to it. If you have received this email in error, please contact the sender immediately and delete this message from any computer or other data bank, Thank you.

A informação transmitida é confidencial e para conhecimento exclusivo do destinatário. Sua utilização, não autorizada, constitui crime passível de prisão. Todas as precauções possíveis foram tomadas para garantir que este e-mail não contenha vírus. Uma vez que nossa empresa não pode assumir responsabilidade por nenhuma perda ou dano causado por este e-mail ou de seus anexos, recomendamos que o destinatário utilize seus procedimentos de antivírus antes de qualquer uso.

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Joe_Smith · July 1, 2014, 5:26am

Hi Chris,

Thank you very much for your reply, especially for reminding me the
conversion of the unit between foot candela and lux!

May I ask the following questions?

1. why the hdr fisheye image needs to be rotated along x axis for 90
degrees and along z axis for 180 degrees? using the fisheye.cal file as
reference when defining the colorpict "skypict"?

2. why "skypict is used as a modifier to define the "glow" material
"groundglow"? I thought usually this position is set as "void"

Using your approach, I tried some other hdr image provided by your project,
and it seems the global horizontal illuminance is always underestimated as
compared to the one reported in the csv file.

rubbing my head about this issue, and advices are greatly appreciated!

Regards,
Joe

···

On Tue, Jul 1, 2014 at 3:06 AM, Christian Humann <chris@christianhumann.com> wrote:

Hi Joe,

The global values in the CSV file are in footcandles so you will need to
multiply them by 10.76 in order to get Lux.

Also, you'll need to add a source description for the sun in order to get
the solar contribution as the camera sensor can not capture the intensity
of the sun for the HDR image. Essentially the HDR image allows you to get
a close approximation of the global diffuse value. I use gendaylit (see
below) to generate the sun and sky scene. You can get the altitude,
azimuth, direct-normal-illuminance and diffuse-horizontal-illuminance from
the CSV file (be sure to multiply the latter two values by 10.76 to
translate them from footcandles to Lux for input into Gendaylit). Also be
sure to adjust your 'rtrace' results by dividing by 10.76 to get
footcandles if you want to compare to the global-horizontal-illuminacne
readings in the CSV file.

########Sun and Sky scene -----> global.rad
!gendaylit -ang 45.41 85.92 -w -O 0 -L 80463.28 19916.76 | xform -e -rz 0
void colorpict skypict
11 red green blue 140621_1530.hdr fisheye.cal fish_u fish_v -rx 90 -rz 180
0
0

skypict glow skyglow
0
0
4 1 1 1 1

skyglow source sky
0
0
4 0 0 1 180

skypict glow groundglow
0
0
4 1 1 1 0

groundglow source ground
0
0
4 0 0 -1 180
#########
# 3. the cmd.sh file
oconv ./global.rad > ./scene_empty.oct

echo '0 0 0 0 0 1' | rtrace -I -h -w -ab 1 -oov ./scene_empty.oct >
./results_position_irradiance_RGB_wm2.txt

cat ./results_position_irradiance_RGB_wm2.txt | rcalc -e
'$1=179*(0.265*$4+0.670*$5+0.065*$6)/10.76' > ./results_illuminance_lux.txt
##########

When I run the above I get a global horizontal illuminance value from
'rtrace' of approx. 6900 footcandles. The photometer gave a reading of
7176 footcandles.

I'm still working my brain around all this as well and hope that these
discussions will foster a better understanding of how to use the HDR images
for the highest level of accuracy possible.

Hope this helps.

Best,
Chris

On Jun 28, 2014, at 10:06 AM, Joe Smith <the.oat.cracker@gmail.com> wrote:

Hi, I found 2 references and did a test to generate HDR image-based
rendering, steps are explained below.

But I'm still rubbing my head to understand how the Cartesian coordinates
or the postion vector of a point on the sky is transformed as UV
coordinates of the fisheye image as shown in the "angmap.cal" file. So,
advices are greatly appreciated!

Thanks!
Joe

References:
1. Debevec, P. (2002). Image-based lighting. IEEE Computer Graphics and
Applications, 22(2), 26-34. doi: 10.1109/38.988744
2. Au, P. Y. P. (2013). HDR Luminance Measurement: Comparing real and
simulated data. (Master of Building Science Thesis), Victoria University of
Wellington.

Steps:
Step1. prepare the following 6 files and put them in the same folder

#### 1.1 geom.rad ################################################
red_plastic sphere ball
0
0
4 2 2 0.5 0.5

steel sphere ball1
0
0
4 2 -2 0.5 0.5

gold sphere ball2
0
0
4 -2 -2 0.5 0.5

white_matte sphere ball3
0
0
4 -2 2 0.5 0.5

crystal sphere ball4
0
0
4 0 0 1 1

!genbox gray_plastic pedestal_top 8 8 0.5 | xform -t -4 -4 -0.5

#### 1.2 materials.mat ################################################
void plastic red_plastic
0
0
5 .7 .1 .1 .06 .1

void metal steel
0
0
5 0.6 0.62 0.68 1 0

void metal gold
0
0
5 0.75 0.55 0.25 0.85 0.2

void plastic white_matte
0
0
5 .8 .8 .8 0 0

void dielectric crystal
0
0
5 .5 .5 .5 1.5 0

void plastic black_matte
0
0
5 .02 .02 .02 .00 .00

void plastic gray_plastic
0
0
5 0.25 0.25 0.25 0.06 0.0

#### 1.3 sky_and_ground.rad
################################################
void colorpict hdr_image
7 red green blue 140621_1530.hdr angmap.cal u v
0
0

hdr_image glow sky_glow
0
0
4 1 1 1 0

sky_glow source HDR_sky
0
0
4 0 0 1 180

# ground
void glow ground_glow
0
0
4 1 1 1 0

ground_glow source ground
0
0
4 0 0 -1 180

#### 1.4 angmap.cal ################################################
{
angmap.cal

Convert from directions in the world (Dx, Dy, Dz) into (u,v)
coordinates on the light probe image

+z is up (toward top of sphere, i.e. the zenith)
+y is North
}

d = sqrt(Dx*Dx + Dy*Dy);

r = acos(Dz)/PI;

u = 0.5 - Dx/d * r;
v = 0.5 + Dy/d * r;

#### 1.5 view.vf ################################################
# looking towards east
#rvu -vtv -vp -12 0 0.5 -vd 1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards west
#rvu -vtv -vp 12 0 0.5 -vd -1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards north
rvu -vtv -vp 0 -12 0.5 -vd 0 1 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards south
#rvu -vtv -vp 0 12 0.5 -vd 0 -1 0 -vu 0 0 1 -vh 60 -vv 40

#### 1.6 cmd.sh ################################################
oconv ./materials.mat ./sky_and_ground.rad ./geom.rad > ./scene.oct

rvu -vf ./view.vf ./scene.oct

#ximage ./sky.hdr

rpict -x 2400 -y 2400 -t 30 -ab 1 -ar 50000 -aa 0.08 -ad 128 -as 64 -st 0
-lw 0 -lr 8 -vf ./view.vf ./scene.oct > ./image.hdr

pfilt -1 -x /3 -y /3 -r 1 ./image.hdr > ./image_filtered.hdr

Step2. put the 140621_1530.hdr file provided by LBNL (
http://flexskycam.lbl.gov) in the same folder

Step3. run the cmd.sh batch file to produce the rendering

On Sat, Jun 28, 2014 at 7:28 AM, Andrew McNeil <amcneil@lbl.gov> wrote:

Hi All,

I haven't done any testing myself, I wanted to make the data available
right away so that others could tinker too (and maybe make it easier for
me).

Joe - You're correct that the HDR sky image essentially replaces the
skyfunc modifier, here's a thread where Kyle was doing the same thing:
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008962.html

Rob - In a clear sky condition our HDR images won't capture the full
luminance of the sun. Mksource would be helpful to zero out the pixels, but
the source that it makes won't be useful without adjusting the radiance of
the source to match that of the sun.

Best,
Andy

On Fri, Jun 27, 2014 at 2:58 PM, Rob Guglielmetti < >> rob.guglielmetti@gmail.com> wrote:

Hi German, and everyone else. Certainly one could use these HDR images
to generate sky vectors and apply them to daylight coefficients for a given
model(s). Greg Ward has created a cool tool called mksource to facilitate
this process in Radiance, identifying small, intense pixels in the image;
creating and placing Radiance light sources in their stead, and zeroing the
pixels to avoid double counting.

Considerations:
- Capturing the true (full) dynamic range of an exterior scene with
direct sun is difficult.
- Using locally-captured HDR images for daylight availability analysis
is statistically dubious. Granted, so is using TMY data, for different
reasons. This is why I changed the title of this list to "considerations",
from "problems". =)

On Fri, Jun 27, 2014 at 3:38 PM, CHI-German Molina <gmolina@hdlao.com> >>> wrote:

Wow, I have been thinking on doing this for a while... although I have
no idea where to start from.

Is it possible to calculate the Daylight Coefficients of the building;
and use the HDR image to generate sky vectors and calculate different
options for optimizing daylighting?

I am picturing a computer that, every 5 minutes, calculate the sky
vector, computes the interior lighting conditions, and simulates the
different lighting options performing a whole-building lighting control
with no photo sensors. Even more, maybe a whole neighborhood could use the
same camera. Nonsense?

Thanks for sharing!

2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker@gmail.com>:

Hi, Andy, thanks for sharing LBNL's sky mapping experiment!

Can you kindly advice on resources that elaborate on how to use HDR
sky image for daylight simulation? Does it involve specifying the HDR
image, rather than a "skyfunc", as the material identifier for the sky
geometry? How is the pixel value of a given point on the HDR image
converted to luminance value of the corresponding position on the sky?

Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov>于2014年6月27日星期五写道：

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site:
http://flexskycam.lbl.gov. I've uploaded sample data, including hdr
images and csv datafiles, recorded by the camera for three days over the
past week( clear, partly cloudy and overcast). We're happy to share more
data with other researchers and daylight practitioners (but we don't have
much to offer yet).

The images can be mapped to a Radiance sky for simulation under real
sky conditions. I have not used the sky HDR images yet, myself, so if
anybody uses them successfully please report back and share what you've
done!

Questions about the camera hardware and capabilities should be
directed to Chris Humann at Terrestrial Light.

Best,
Andy

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
*Germán Molina L.*
Ingeniero Trainee
Hunter Douglas Chile S.A.
Celular +569 89224445

*Nota de Confidencialidad:* Este mensaje incluído los archivos
adjuntos son confidenciales y pueden contener informacion privilegiada
protegida por ley. Si Ud. no es el destinatario, deberia abstenerse de
copiarlo, distribuirlo, divulgarlo o usar la informacion contenida. Por
favor, avise inmediatamente al emisor y borre este mensaje de su sistema.
Los mensajes electronicos son susceptibles de ser cambiados, infectados o
adulterados sin autorizacion. No asumimos responsabilidad alguna por
ninguna clase de cambios o sus consecuencias. Usted debe estar informado
que la compania puede hacer un seguimiento de sus mensajes electronicos y
su contenido, gracias.

*Confidentiality Notice:* The information contained in this email
message, including any attachment, is confidential and is intended only for
the person or entity to which it is addressed. If you are neither the
intended recipient nor the employee or agent responsible for delivering
this message to the intended recipient, you are hereby notified that you
may not review, retransmit, convert to hard copy, copy, use or distribute
this email message or any attachments to it. If you have received this
email in error, please contact the sender immediately and delete this
message from any computer or other data bank, Thank you.

A informação transmitida é confidencial e para conhecimento exclusivo
do destinatário. Sua utilização, não autorizada, constitui crime passível
de prisão. Todas as precauções possíveis foram tomadas para garantir que
este e-mail não contenha vírus. Uma vez que nossa empresa não pode assumir
responsabilidade por nenhuma perda ou dano causado por este e-mail ou de
seus anexos, recomendamos que o destinatário utilize seus procedimentos de
antivírus antes de qualquer uso.

_______________________________________________
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Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

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Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

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Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

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Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

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Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

Joe_Smith · July 1, 2014, 5:55am

BTW, found some references on direct HDR capture of the sun by Jessi
Stumpfel:

Stumpfel, J., Jones, A., Wenger, A., Tchou, C., Hawkins, T., & Debevec, P.
(2004). Direct HDR Capture of the Sun and Sky.

Stumpfel, J., Jones, A., Wenger, A., & Debevec, P. (2004). Direct HDR
capture of the sun and sky. Paper presented at the 3rd International
Conference on Virtual Reality, Computer Graphics, Visualization and
Interaction in Africa, Cape Town, South Africa.

Stumpfel, J. (2004). HDR Lighting Capture of the Sky and Sun. (Master of
Science Thesis), California Institute of Technology. Retrieved from

- Joe

···

On Tue, Jul 1, 2014 at 3:06 AM, Christian Humann <chris@christianhumann.com> wrote:

Hi Joe,

The global values in the CSV file are in footcandles so you will need to
multiply them by 10.76 in order to get Lux.

Also, you'll need to add a source description for the sun in order to get
the solar contribution as the camera sensor can not capture the intensity
of the sun for the HDR image. Essentially the HDR image allows you to get
a close approximation of the global diffuse value. I use gendaylit (see
below) to generate the sun and sky scene. You can get the altitude,
azimuth, direct-normal-illuminance and diffuse-horizontal-illuminance from
the CSV file (be sure to multiply the latter two values by 10.76 to
translate them from footcandles to Lux for input into Gendaylit). Also be
sure to adjust your 'rtrace' results by dividing by 10.76 to get
footcandles if you want to compare to the global-horizontal-illuminacne
readings in the CSV file.

########Sun and Sky scene -----> global.rad
!gendaylit -ang 45.41 85.92 -w -O 0 -L 80463.28 19916.76 | xform -e -rz 0
void colorpict skypict
11 red green blue 140621_1530.hdr fisheye.cal fish_u fish_v -rx 90 -rz 180
0
0

skypict glow skyglow
0
0
4 1 1 1 1

skyglow source sky
0
0
4 0 0 1 180

skypict glow groundglow
0
0
4 1 1 1 0

groundglow source ground
0
0
4 0 0 -1 180
#########
# 3. the cmd.sh file
oconv ./global.rad > ./scene_empty.oct

echo '0 0 0 0 0 1' | rtrace -I -h -w -ab 1 -oov ./scene_empty.oct >
./results_position_irradiance_RGB_wm2.txt

cat ./results_position_irradiance_RGB_wm2.txt | rcalc -e
'$1=179*(0.265*$4+0.670*$5+0.065*$6)/10.76' > ./results_illuminance_lux.txt
##########

When I run the above I get a global horizontal illuminance value from
'rtrace' of approx. 6900 footcandles. The photometer gave a reading of
7176 footcandles.

I'm still working my brain around all this as well and hope that these
discussions will foster a better understanding of how to use the HDR images
for the highest level of accuracy possible.

Hope this helps.

Best,
Chris

On Jun 28, 2014, at 10:06 AM, Joe Smith <the.oat.cracker@gmail.com> wrote:

Hi, I found 2 references and did a test to generate HDR image-based
rendering, steps are explained below.

But I'm still rubbing my head to understand how the Cartesian coordinates
or the postion vector of a point on the sky is transformed as UV
coordinates of the fisheye image as shown in the "angmap.cal" file. So,
advices are greatly appreciated!

Thanks!
Joe

References:
1. Debevec, P. (2002). Image-based lighting. IEEE Computer Graphics and
Applications, 22(2), 26-34. doi: 10.1109/38.988744
2. Au, P. Y. P. (2013). HDR Luminance Measurement: Comparing real and
simulated data. (Master of Building Science Thesis), Victoria University of
Wellington.

Steps:
Step1. prepare the following 6 files and put them in the same folder

#### 1.1 geom.rad ################################################
red_plastic sphere ball
0
0
4 2 2 0.5 0.5

steel sphere ball1
0
0
4 2 -2 0.5 0.5

gold sphere ball2
0
0
4 -2 -2 0.5 0.5

white_matte sphere ball3
0
0
4 -2 2 0.5 0.5

crystal sphere ball4
0
0
4 0 0 1 1

!genbox gray_plastic pedestal_top 8 8 0.5 | xform -t -4 -4 -0.5

#### 1.2 materials.mat ################################################
void plastic red_plastic
0
0
5 .7 .1 .1 .06 .1

void metal steel
0
0
5 0.6 0.62 0.68 1 0

void metal gold
0
0
5 0.75 0.55 0.25 0.85 0.2

void plastic white_matte
0
0
5 .8 .8 .8 0 0

void dielectric crystal
0
0
5 .5 .5 .5 1.5 0

void plastic black_matte
0
0
5 .02 .02 .02 .00 .00

void plastic gray_plastic
0
0
5 0.25 0.25 0.25 0.06 0.0

#### 1.3 sky_and_ground.rad
################################################
void colorpict hdr_image
7 red green blue 140621_1530.hdr angmap.cal u v
0
0

hdr_image glow sky_glow
0
0
4 1 1 1 0

sky_glow source HDR_sky
0
0
4 0 0 1 180

# ground
void glow ground_glow
0
0
4 1 1 1 0

ground_glow source ground
0
0
4 0 0 -1 180

#### 1.4 angmap.cal ################################################
{
angmap.cal

Convert from directions in the world (Dx, Dy, Dz) into (u,v)
coordinates on the light probe image

+z is up (toward top of sphere, i.e. the zenith)
+y is North
}

d = sqrt(Dx*Dx + Dy*Dy);

r = acos(Dz)/PI;

u = 0.5 - Dx/d * r;
v = 0.5 + Dy/d * r;

#### 1.5 view.vf ################################################
# looking towards east
#rvu -vtv -vp -12 0 0.5 -vd 1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards west
#rvu -vtv -vp 12 0 0.5 -vd -1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards north
rvu -vtv -vp 0 -12 0.5 -vd 0 1 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards south
#rvu -vtv -vp 0 12 0.5 -vd 0 -1 0 -vu 0 0 1 -vh 60 -vv 40

#### 1.6 cmd.sh ################################################
oconv ./materials.mat ./sky_and_ground.rad ./geom.rad > ./scene.oct

rvu -vf ./view.vf ./scene.oct

#ximage ./sky.hdr

rpict -x 2400 -y 2400 -t 30 -ab 1 -ar 50000 -aa 0.08 -ad 128 -as 64 -st 0
-lw 0 -lr 8 -vf ./view.vf ./scene.oct > ./image.hdr

pfilt -1 -x /3 -y /3 -r 1 ./image.hdr > ./image_filtered.hdr

Step2. put the 140621_1530.hdr file provided by LBNL (
http://flexskycam.lbl.gov) in the same folder

Step3. run the cmd.sh batch file to produce the rendering

On Sat, Jun 28, 2014 at 7:28 AM, Andrew McNeil <amcneil@lbl.gov> wrote:

Hi All,

I haven't done any testing myself, I wanted to make the data available
right away so that others could tinker too (and maybe make it easier for
me).

Joe - You're correct that the HDR sky image essentially replaces the
skyfunc modifier, here's a thread where Kyle was doing the same thing:
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008962.html

Rob - In a clear sky condition our HDR images won't capture the full
luminance of the sun. Mksource would be helpful to zero out the pixels, but
the source that it makes won't be useful without adjusting the radiance of
the source to match that of the sun.

Best,
Andy

On Fri, Jun 27, 2014 at 2:58 PM, Rob Guglielmetti < >> rob.guglielmetti@gmail.com> wrote:

Hi German, and everyone else. Certainly one could use these HDR images
to generate sky vectors and apply them to daylight coefficients for a given
model(s). Greg Ward has created a cool tool called mksource to facilitate
this process in Radiance, identifying small, intense pixels in the image;
creating and placing Radiance light sources in their stead, and zeroing the
pixels to avoid double counting.

Considerations:
- Capturing the true (full) dynamic range of an exterior scene with
direct sun is difficult.
- Using locally-captured HDR images for daylight availability analysis
is statistically dubious. Granted, so is using TMY data, for different
reasons. This is why I changed the title of this list to "considerations",
from "problems". =)

On Fri, Jun 27, 2014 at 3:38 PM, CHI-German Molina <gmolina@hdlao.com> >>> wrote:

Wow, I have been thinking on doing this for a while... although I have
no idea where to start from.

Is it possible to calculate the Daylight Coefficients of the building;
and use the HDR image to generate sky vectors and calculate different
options for optimizing daylighting?

I am picturing a computer that, every 5 minutes, calculate the sky
vector, computes the interior lighting conditions, and simulates the
different lighting options performing a whole-building lighting control
with no photo sensors. Even more, maybe a whole neighborhood could use the
same camera. Nonsense?

Thanks for sharing!

2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker@gmail.com>:

Hi, Andy, thanks for sharing LBNL's sky mapping experiment!

Can you kindly advice on resources that elaborate on how to use HDR
sky image for daylight simulation? Does it involve specifying the HDR
image, rather than a "skyfunc", as the material identifier for the sky
geometry? How is the pixel value of a given point on the HDR image
converted to luminance value of the corresponding position on the sky?

Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov>于2014年6月27日星期五写道：

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site:
http://flexskycam.lbl.gov. I've uploaded sample data, including hdr
images and csv datafiles, recorded by the camera for three days over the
past week( clear, partly cloudy and overcast). We're happy to share more
data with other researchers and daylight practitioners (but we don't have
much to offer yet).

The images can be mapped to a Radiance sky for simulation under real
sky conditions. I have not used the sky HDR images yet, myself, so if
anybody uses them successfully please report back and share what you've
done!

Questions about the camera hardware and capabilities should be
directed to Chris Humann at Terrestrial Light.

Best,
Andy

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
*Germán Molina L.*
Ingeniero Trainee
Hunter Douglas Chile S.A.
Celular +569 89224445

*Nota de Confidencialidad:* Este mensaje incluído los archivos
adjuntos son confidenciales y pueden contener informacion privilegiada
protegida por ley. Si Ud. no es el destinatario, deberia abstenerse de
copiarlo, distribuirlo, divulgarlo o usar la informacion contenida. Por
favor, avise inmediatamente al emisor y borre este mensaje de su sistema.
Los mensajes electronicos son susceptibles de ser cambiados, infectados o
adulterados sin autorizacion. No asumimos responsabilidad alguna por
ninguna clase de cambios o sus consecuencias. Usted debe estar informado
que la compania puede hacer un seguimiento de sus mensajes electronicos y
su contenido, gracias.

*Confidentiality Notice:* The information contained in this email
message, including any attachment, is confidential and is intended only for
the person or entity to which it is addressed. If you are neither the
intended recipient nor the employee or agent responsible for delivering
this message to the intended recipient, you are hereby notified that you
may not review, retransmit, convert to hard copy, copy, use or distribute
this email message or any attachments to it. If you have received this
email in error, please contact the sender immediately and delete this
message from any computer or other data bank, Thank you.

A informação transmitida é confidencial e para conhecimento exclusivo
do destinatário. Sua utilização, não autorizada, constitui crime passível
de prisão. Todas as precauções possíveis foram tomadas para garantir que
este e-mail não contenha vírus. Uma vez que nossa empresa não pode assumir
responsabilidade por nenhuma perda ou dano causado por este e-mail ou de
seus anexos, recomendamos que o destinatário utilize seus procedimentos de
antivírus antes de qualquer uso.

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

Mehlika_Inanici · July 1, 2014, 6:16am

The following are also on the topic:

from 2009 Radiance worksop: http://www.gsd.harvard.edu/research/gsdsquare/Presentations/inanici_Radiance2009.pdf

Inanici M. “Evaluation of High Dynamic Range Image-based Sky Models in Lighting Simulation,” Luekos, Journal of the Illuminating Engineering Society (IES), 7(2), October 2010, 69-84. [pre-pint version is available at: http://faculty.washington.edu/inanici/Publications/mi-luekos2010.pdf

Hope it is helpful,
Mehlika

···

On Tue, 1 Jul 2014, Joe Smith wrote:

BTW, found some references on direct HDR capture of the sun by Jessi Stumpfel:

Stumpfel, J., Jones, A., Wenger, A., Tchou, C., Hawkins, T., & Debevec, P. (2004). Direct HDR Capture of the Sun and Sky.
http://gl.ict.usc.edu/Data/skyprobes/skycapture_poster.pdf

Stumpfel, J., Jones, A., Wenger, A., & Debevec, P. (2004). Direct HDR capture of the sun and sky. Paper presented at the 3rd
International Conference on Virtual Reality, Computer Graphics, Visualization and Interaction in Africa, Cape Town, South
Africa.

Stumpfel, J. (2004). HDR Lighting Capture of the Sky and Sun. (Master of Science Thesis), California Institute of Technology.
Retrieved from http://gl.ict.usc.edu/Data/skyprobes/ms_thesis_stumpfel.pdf

- Joe

On Tue, Jul 1, 2014 at 3:06 AM, Christian Humann <chris@christianhumann.com> wrote:
      Hi Joe,
The global values in the CSV file are in footcandles so you will need to multiply them by 10.76 in order to get Lux.

Also, you'll need to add a source description for the sun in order to get the solar contribution as the camera sensor can
not capture the intensity of the sun for the HDR image. Essentially the HDR image allows you to get a close
approximation of the global diffuse value. I use gendaylit (see below) to generate the sun and sky scene. You can get
the altitude, azimuth, direct-normal-illuminance and diffuse-horizontal-illuminance from the CSV file (be sure to
multiply the latter two values by 10.76 to translate them from footcandles to Lux for input into Gendaylit). Also be sure
to adjust your 'rtrace' results by dividing by 10.76 to get footcandles if you want to compare to the
global-horizontal-illuminacne readings in the CSV file.

########Sun and Sky scene -----> global.rad
!gendaylit -ang 45.41 85.92 -w -O 0 -L 80463.28 19916.76 | xform -e -rz 0
void colorpict skypict
11 red green blue 140621_1530.hdr fisheye.cal fish_u fish_v -rx 90 -rz 180
0

skypict glow skyglow
0
4 1 1 1 1

skyglow source sky
0
4 0 0 1 180

skypict glow groundglow
0
4 1 1 1 0

groundglow source ground
0
4 0 0 -1 180
#########
# 3. the cmd.sh file
oconv ./global.rad > ./scene_empty.oct

echo '0 0 0 0 0 1' | rtrace -I -h -w -ab 1 -oov ./scene_empty.oct > ./results_position_irradiance_RGB_wm2.txt

cat ./results_position_irradiance_RGB_wm2.txt | rcalc -e '$1=179*(0.265*$4+0.670*$5+0.065*$6)/10.76' >
./results_illuminance_lux.txt
##########

When I run the above I get a global horizontal illuminance value from 'rtrace' of approx. 6900 footcandles. The
photometer gave a reading of 7176 footcandles.

I'm still working my brain around all this as well and hope that these discussions will foster a better understanding of
how to use the HDR images for the highest level of accuracy possible.

Hope this helps.

Best,
Chris

On Jun 28, 2014, at 10:06 AM, Joe Smith <the.oat.cracker@gmail.com> wrote:

      Hi, I found 2 references and did a test to generate HDR image-based rendering, steps are explained below.

      But I'm still rubbing my head to understand how the Cartesian coordinates or the postion vector of a point on
      the sky is transformed as UV coordinates of the fisheye image as shown in the "angmap.cal" file. So, advices
      are greatly appreciated!

      Thanks!
      Joe

      References:
      1. Debevec, P. (2002). Image-based lighting. IEEE Computer Graphics and Applications, 22(2), 26-34. doi:
      10.1109/38.988744
      2. Au, P. Y. P. (2013). HDR Luminance Measurement: Comparing real and simulated data. (Master of Building
      Science Thesis), Victoria University of Wellington.

      Steps:
      Step1. prepare the following 6 files and put them in the same folder

      #### 1.1 geom.rad ################################################
      red_plastic sphere ball
      0
      4 2 2 0.5 0.5

      steel sphere ball1
      0
      4 2 -2 0.5 0.5

      gold sphere ball2
      0
      4 -2 -2 0.5 0.5

      white_matte sphere ball3
      0
      4 -2 2 0.5 0.5

      crystal sphere ball4
      0
      4 0 0 1 1

      !genbox gray_plastic pedestal_top 8 8 0.5 | xform -t -4 -4 -0.5

      #### 1.2 materials.mat ################################################
      void plastic red_plastic
      0
      5 .7 .1 .1 .06 .1

      void metal steel
      0
      5 0.6 0.62 0.68 1 0

      void metal gold
      0
      5 0.75 0.55 0.25 0.85 0.2

      void plastic white_matte
      0
      5 .8 .8 .8 0 0

      void dielectric crystal
      0
      5 .5 .5 .5 1.5 0

      void plastic black_matte
      0
      5 .02 .02 .02 .00 .00

      void plastic gray_plastic
      0
      5 0.25 0.25 0.25 0.06 0.0

      #### 1.3 sky_and_ground.rad ################################################
      void colorpict hdr_image
      7 red green blue 140621_1530.hdr angmap.cal u v
      0

      hdr_image glow sky_glow
      0
      4 1 1 1 0

      sky_glow source HDR_sky
      0
      4 0 0 1 180

      # ground
      void glow ground_glow
      0
      4 1 1 1 0

      ground_glow source ground
      0
      4 0 0 -1 180

      #### 1.4 angmap.cal ################################################
      {
      angmap.cal

      Convert from directions in the world (Dx, Dy, Dz) into (u,v)
      coordinates on the light probe image

      +z is up (toward top of sphere, i.e. the zenith)
      +y is North
      }

      d = sqrt(Dx*Dx + Dy*Dy);

      r = acos(Dz)/PI;

      u = 0.5 - Dx/d * r;
      v = 0.5 + Dy/d * r;

      #### 1.5 view.vf ################################################
      # looking towards east
      #rvu -vtv -vp -12 0 0.5 -vd 1 0 0 -vu 0 0 1 -vh 60 -vv 40
      # looking towards west
      #rvu -vtv -vp 12 0 0.5 -vd -1 0 0 -vu 0 0 1 -vh 60 -vv 40
      # looking towards north
      rvu -vtv -vp 0 -12 0.5 -vd 0 1 0 -vu 0 0 1 -vh 60 -vv 40
      # looking towards south
      #rvu -vtv -vp 0 12 0.5 -vd 0 -1 0 -vu 0 0 1 -vh 60 -vv 40

      #### 1.6 cmd.sh ################################################
      oconv ./materials.mat ./sky_and_ground.rad ./geom.rad > ./scene.oct

      rvu -vf ./view.vf ./scene.oct

      #ximage ./sky.hdr

      rpict -x 2400 -y 2400 -t 30 -ab 1 -ar 50000 -aa 0.08 -ad 128 -as 64 -st 0 -lw 0 -lr 8 -vf ./view.vf
      ./scene.oct > ./image.hdr

      pfilt -1 -x /3 -y /3 -r 1 ./image.hdr > ./image_filtered.hdr

      Step2. put the 140621_1530.hdr file provided by LBNL (http://flexskycam.lbl.gov) in the same folder

      Step3. run the cmd.sh batch file to produce the rendering

      On Sat, Jun 28, 2014 at 7:28 AM, Andrew McNeil <amcneil@lbl.gov> wrote:
            Hi All,
            I haven't done any testing myself, I wanted to make the data available right away so that others
            could tinker too (and maybe make it easier for me).

Joe - You're correct that the HDR sky image essentially replaces the skyfunc modifier, here's a thread where
Kyle was doing the same thing:
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008962.html

Rob - In a clear sky condition our HDR images won't capture the full luminance of the sun. Mksource would be
helpful to zero out the pixels, but the source that it makes won't be useful without adjusting the radiance
of the source to match that of the sun.

Best,
Andy

On Fri, Jun 27, 2014 at 2:58 PM, Rob Guglielmetti <rob.guglielmetti@gmail.com> wrote:
      Hi German, and everyone else. Certainly one could use these HDR images to generate sky vectors
      and apply them to daylight coefficients for a given model(s). Greg Ward has created a cool tool
      called mksource to facilitate this process in Radiance, identifying small, intense pixels in the
      image; creating and placing Radiance light sources in their stead, and zeroing the pixels to
      avoid double counting.
Considerations:
- Capturing the true (full) dynamic range of an exterior scene with direct sun is difficult.
- Using locally-captured HDR images for daylight availability analysis is statistically dubious.
Granted, so is using TMY data, for different reasons. This is why I changed the title of this list to
"considerations", from "problems". =)

On Fri, Jun 27, 2014 at 3:38 PM, CHI-German Molina <gmolina@hdlao.com> wrote:
      Wow, I have been thinking on doing this for a while... although I have no idea where to
      start from.
Is it possible to calculate the Daylight Coefficients of the building; and use the HDR image to
generate sky vectors and calculate different options for optimizing daylighting?

I am picturing a computer that, every 5 minutes, calculate the sky vector, computes the interior
lighting conditions, and simulates the different lighting options performing a whole-building
lighting control with no photo sensors. Even more, maybe a whole neighborhood could use the same
camera. Nonsense?

Thanks for sharing!

2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker@gmail.com>:
      Hi, Andy, thanks for sharing LBNL's sky mapping experiment!
Can you kindly advice on resources that elaborate on how to use HDR sky image for daylight
simulation? Does it involve specifying the HDR image, rather than a "skyfunc", as the
material identifier for the sky geometry? How is the pixel value of a given point on the
HDR image converted to luminance value of the corresponding position on the sky?
Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov>于2014年6月27日星期五写道：
      Hi Everyone,
      LBNL has installed an HDR sky camera at our new FLEXLAB
      site: http://flexskycam.lbl.gov. I've uploaded sample data, including hdr
      images and csv datafiles, recorded by the camera for three days over the past
      week( clear, partly cloudy and overcast). We're happy to share more data with
      other researchers and daylight practitioners (but we don't have much to offer
      yet).

The images can be mapped to a Radiance sky for simulation under real sky conditions.
I have not used the sky HDR images yet, myself, so if anybody uses them successfully
please report back and share what you've done!

Questions about the camera hardware and capabilities should be directed to Chris
Humann at Terrestrial Light.

Best,
Andy

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
Germán Molina L.
Ingeniero Trainee
Hunter Douglas Chile S.A.
Celular +569 89224445

Nota de Confidencialidad: Este mensaje incluído los archivos adjuntos son confidenciales y pueden
contener informacion privilegiada protegida por ley. Si Ud. no es el destinatario, deberia
abstenerse de copiarlo, distribuirlo, divulgarlo o usar la informacion contenida. Por favor,
avise inmediatamente al emisor y borre este mensaje de su sistema. Los mensajes electronicos son
susceptibles de ser cambiados, infectados o adulterados sin autorizacion. No asumimos
responsabilidad alguna por ninguna clase de cambios o sus consecuencias. Usted debe estar
informado que la compania puede hacer un seguimiento de sus mensajes electronicos y su contenido,
gracias.

Confidentiality Notice: The information contained in this email message, including any
attachment, is confidential and is intended only for the person or entity to which it is
addressed. If you are neither the intended recipient nor the employee or agent responsible for
delivering this message to the intended recipient, you are hereby notified that you may not
review, retransmit, convert to hard copy, copy, use or distribute this email message or any
attachments to it. If you have received this email in error, please contact the sender
immediately and delete this message from any computer or other data bank, Thank you.

A informação transmitida é confidencial e para conhecimento exclusivo do destinatário. Sua
utilização, não autorizada, constitui crime passível de prisão. Todas as precauções possíveis
foram tomadas para garantir que este e-mail não contenha vírus. Uma vez que nossa empresa não
pode assumir responsabilidade por nenhuma perda ou dano causado por este e-mail ou de seus
anexos, recomendamos que o destinatário utilize seus procedimentos de antivírus antes de qualquer
uso.

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Christian_Humann · July 1, 2014, 3:52pm

Hi Joe,

Thank you for the references.

The HDR image by default is co-planar with the x and z axis with its surface normal pointing in the negative y direction. You'll need to translate the image so that its surface normal is pointed down along the negative z axis and rotate it so that North is up when looking up towards zenith.

The groundglow description is actually not necessary and has no effect. If you wanted to define the ground for inclusion in a scene you could use the following:

void glow groundglow
0
0
4 .15 .15 .15 0 #(.15 .15 .15 = RGB values for the ground material)

groundglow source ground
0
0
4 0 0 -1 180

I too have been getting lower values than the measured global horizontal illuminance. I think the suggestions made made by Rob and Greg about using mksource and adjusting the subtended angle of the solar source may be the solution. Not sure yet how to implement the latter but I will certainly keep you posted.

Cheers,
Chris

···

On Jun 30, 2014, at 10:26 PM, Joe Smith <the.oat.cracker@gmail.com> wrote:

Hi Chris,

Thank you very much for your reply, especially for reminding me the conversion of the unit between foot candela and lux!

May I ask the following questions?

1. why the hdr fisheye image needs to be rotated along x axis for 90 degrees and along z axis for 180 degrees? using the fisheye.cal file as reference when defining the colorpict "skypict"?

2. why "skypict is used as a modifier to define the "glow" material "groundglow"? I thought usually this position is set as "void"

Using your approach, I tried some other hdr image provided by your project, and it seems the global horizontal illuminance is always underestimated as compared to the one reported in the csv file.

rubbing my head about this issue, and advices are greatly appreciated!

Regards,
Joe

On Tue, Jul 1, 2014 at 3:06 AM, Christian Humann <chris@christianhumann.com> wrote:
Hi Joe,

The global values in the CSV file are in footcandles so you will need to multiply them by 10.76 in order to get Lux.

Also, you'll need to add a source description for the sun in order to get the solar contribution as the camera sensor can not capture the intensity of the sun for the HDR image. Essentially the HDR image allows you to get a close approximation of the global diffuse value. I use gendaylit (see below) to generate the sun and sky scene. You can get the altitude, azimuth, direct-normal-illuminance and diffuse-horizontal-illuminance from the CSV file (be sure to multiply the latter two values by 10.76 to translate them from footcandles to Lux for input into Gendaylit). Also be sure to adjust your 'rtrace' results by dividing by 10.76 to get footcandles if you want to compare to the global-horizontal-illuminacne readings in the CSV file.

########Sun and Sky scene -----> global.rad
!gendaylit -ang 45.41 85.92 -w -O 0 -L 80463.28 19916.76 | xform -e -rz 0
void colorpict skypict
11 red green blue 140621_1530.hdr fisheye.cal fish_u fish_v -rx 90 -rz 180
0
0

skypict glow skyglow
0
0
4 1 1 1 1

skyglow source sky
0
0
4 0 0 1 180

skypict glow groundglow
0
0
4 1 1 1 0

groundglow source ground
0
0
4 0 0 -1 180
#########
# 3. the cmd.sh file
oconv ./global.rad > ./scene_empty.oct

echo '0 0 0 0 0 1' | rtrace -I -h -w -ab 1 -oov ./scene_empty.oct > ./results_position_irradiance_RGB_wm2.txt

cat ./results_position_irradiance_RGB_wm2.txt | rcalc -e '$1=179*(0.265*$4+0.670*$5+0.065*$6)/10.76' > ./results_illuminance_lux.txt
##########

When I run the above I get a global horizontal illuminance value from 'rtrace' of approx. 6900 footcandles. The photometer gave a reading of 7176 footcandles.

I'm still working my brain around all this as well and hope that these discussions will foster a better understanding of how to use the HDR images for the highest level of accuracy possible.

Hope this helps.

Best,
Chris

On Jun 28, 2014, at 10:06 AM, Joe Smith <the.oat.cracker@gmail.com> wrote:

Hi, I found 2 references and did a test to generate HDR image-based rendering, steps are explained below.

But I'm still rubbing my head to understand how the Cartesian coordinates or the postion vector of a point on the sky is transformed as UV coordinates of the fisheye image as shown in the "angmap.cal" file. So, advices are greatly appreciated!

Thanks!
Joe

References:
1. Debevec, P. (2002). Image-based lighting. IEEE Computer Graphics and Applications, 22(2), 26-34. doi: 10.1109/38.988744
2. Au, P. Y. P. (2013). HDR Luminance Measurement: Comparing real and simulated data. (Master of Building Science Thesis), Victoria University of Wellington.

Steps:
Step1. prepare the following 6 files and put them in the same folder

#### 1.1 geom.rad ################################################
red_plastic sphere ball
0
0
4 2 2 0.5 0.5

steel sphere ball1
0
0
4 2 -2 0.5 0.5

gold sphere ball2
0
0
4 -2 -2 0.5 0.5

white_matte sphere ball3
0
0
4 -2 2 0.5 0.5

crystal sphere ball4
0
0
4 0 0 1 1

!genbox gray_plastic pedestal_top 8 8 0.5 | xform -t -4 -4 -0.5

#### 1.2 materials.mat ################################################
void plastic red_plastic
0
0
5 .7 .1 .1 .06 .1

void metal steel
0
0
5 0.6 0.62 0.68 1 0

void metal gold
0
0
5 0.75 0.55 0.25 0.85 0.2

void plastic white_matte
0
0
5 .8 .8 .8 0 0

void dielectric crystal
0
0
5 .5 .5 .5 1.5 0

void plastic black_matte
0
0
5 .02 .02 .02 .00 .00

void plastic gray_plastic
0
0
5 0.25 0.25 0.25 0.06 0.0

#### 1.3 sky_and_ground.rad ################################################
void colorpict hdr_image
7 red green blue 140621_1530.hdr angmap.cal u v
0
0

hdr_image glow sky_glow
0
0
4 1 1 1 0

sky_glow source HDR_sky
0
0
4 0 0 1 180

# ground
void glow ground_glow
0
0
4 1 1 1 0

ground_glow source ground
0
0
4 0 0 -1 180

#### 1.4 angmap.cal ################################################
{
angmap.cal

Convert from directions in the world (Dx, Dy, Dz) into (u,v)
coordinates on the light probe image

+z is up (toward top of sphere, i.e. the zenith)
+y is North
}

d = sqrt(Dx*Dx + Dy*Dy);

r = acos(Dz)/PI;

u = 0.5 - Dx/d * r;
v = 0.5 + Dy/d * r;

#### 1.5 view.vf ################################################
# looking towards east
#rvu -vtv -vp -12 0 0.5 -vd 1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards west
#rvu -vtv -vp 12 0 0.5 -vd -1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards north
rvu -vtv -vp 0 -12 0.5 -vd 0 1 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards south
#rvu -vtv -vp 0 12 0.5 -vd 0 -1 0 -vu 0 0 1 -vh 60 -vv 40

#### 1.6 cmd.sh ################################################
oconv ./materials.mat ./sky_and_ground.rad ./geom.rad > ./scene.oct

rvu -vf ./view.vf ./scene.oct

#ximage ./sky.hdr

rpict -x 2400 -y 2400 -t 30 -ab 1 -ar 50000 -aa 0.08 -ad 128 -as 64 -st 0 -lw 0 -lr 8 -vf ./view.vf ./scene.oct > ./image.hdr

pfilt -1 -x /3 -y /3 -r 1 ./image.hdr > ./image_filtered.hdr

Step2. put the 140621_1530.hdr file provided by LBNL (http://flexskycam.lbl.gov) in the same folder

Step3. run the cmd.sh batch file to produce the rendering

On Sat, Jun 28, 2014 at 7:28 AM, Andrew McNeil <amcneil@lbl.gov> wrote:
Hi All,

I haven't done any testing myself, I wanted to make the data available right away so that others could tinker too (and maybe make it easier for me).

Joe - You're correct that the HDR sky image essentially replaces the skyfunc modifier, here's a thread where Kyle was doing the same thing: http://www.radiance-online.org/pipermail/radiance-general/2012-October/008962.html

Rob - In a clear sky condition our HDR images won't capture the full luminance of the sun. Mksource would be helpful to zero out the pixels, but the source that it makes won't be useful without adjusting the radiance of the source to match that of the sun.

Best,
Andy

On Fri, Jun 27, 2014 at 2:58 PM, Rob Guglielmetti <rob.guglielmetti@gmail.com> wrote:
Hi German, and everyone else. Certainly one could use these HDR images to generate sky vectors and apply them to daylight coefficients for a given model(s). Greg Ward has created a cool tool called mksource to facilitate this process in Radiance, identifying small, intense pixels in the image; creating and placing Radiance light sources in their stead, and zeroing the pixels to avoid double counting.

Considerations:
- Capturing the true (full) dynamic range of an exterior scene with direct sun is difficult.
- Using locally-captured HDR images for daylight availability analysis is statistically dubious. Granted, so is using TMY data, for different reasons. This is why I changed the title of this list to "considerations", from "problems". =)

On Fri, Jun 27, 2014 at 3:38 PM, CHI-German Molina <gmolina@hdlao.com> wrote:
Wow, I have been thinking on doing this for a while... although I have no idea where to start from.

Is it possible to calculate the Daylight Coefficients of the building; and use the HDR image to generate sky vectors and calculate different options for optimizing daylighting?

I am picturing a computer that, every 5 minutes, calculate the sky vector, computes the interior lighting conditions, and simulates the different lighting options performing a whole-building lighting control with no photo sensors. Even more, maybe a whole neighborhood could use the same camera. Nonsense?

Thanks for sharing!

2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker@gmail.com>:
Hi, Andy, thanks for sharing LBNL's sky mapping experiment!

Can you kindly advice on resources that elaborate on how to use HDR sky image for daylight simulation? Does it involve specifying the HDR image, rather than a "skyfunc", as the material identifier for the sky geometry? How is the pixel value of a given point on the HDR image converted to luminance value of the corresponding position on the sky?

Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov>于2014年6月27日星期五写道：

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site: http://flexskycam.lbl.gov. I've uploaded sample data, including hdr images and csv datafiles, recorded by the camera for three days over the past week( clear, partly cloudy and overcast). We're happy to share more data with other researchers and daylight practitioners (but we don't have much to offer yet).

The images can be mapped to a Radiance sky for simulation under real sky conditions. I have not used the sky HDR images yet, myself, so if anybody uses them successfully please report back and share what you've done!

Questions about the camera hardware and capabilities should be directed to Chris Humann at Terrestrial Light.

Best,
Andy

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
Germán Molina L.
Ingeniero Trainee
Hunter Douglas Chile S.A.
Celular +569 89224445

Nota de Confidencialidad: Este mensaje incluído los archivos adjuntos son confidenciales y pueden contener informacion privilegiada protegida por ley. Si Ud. no es el destinatario, deberia abstenerse de copiarlo, distribuirlo, divulgarlo o usar la informacion contenida. Por favor, avise inmediatamente al emisor y borre este mensaje de su sistema. Los mensajes electronicos son susceptibles de ser cambiados, infectados o adulterados sin autorizacion. No asumimos responsabilidad alguna por ninguna clase de cambios o sus consecuencias. Usted debe estar informado que la compania puede hacer un seguimiento de sus mensajes electronicos y su contenido, gracias.

Confidentiality Notice: The information contained in this email message, including any attachment, is confidential and is intended only for the person or entity to which it is addressed. If you are neither the intended recipient nor the employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that you may not review, retransmit, convert to hard copy, copy, use or distribute this email message or any attachments to it. If you have received this email in error, please contact the sender immediately and delete this message from any computer or other data bank, Thank you.

A informação transmitida é confidencial e para conhecimento exclusivo do destinatário. Sua utilização, não autorizada, constitui crime passível de prisão. Todas as precauções possíveis foram tomadas para garantir que este e-mail não contenha vírus. Uma vez que nossa empresa não pode assumir responsabilidade por nenhuma perda ou dano causado por este e-mail ou de seus anexos, recomendamos que o destinatário utilize seus procedimentos de antivírus antes de qualquer uso.

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Kyle_Konis · July 1, 2014, 11:10pm

Following up here, (and on the referenced thread from about a year ago), i
did succeed in rendering some simple Radiance objects with HDR skies.

I have uploaded an example video here with the LBNL Skycam images (June 21,
2014 until about 10:40 AM) which was all I could process during the world
cup match:
http://performance-and-form.com/projects/rendering-digital-objects-with-high-dynamic-range-hdr-sky-images/

Thanks are due to Coralie Cauwerts for corresponding to provide me with the
proper .cal file for mapping hemispherical (rather than spherical) images.

The skies are used to render a chrome sphere sitting on a pedestal. You can
tell it is not a real object because it is outside for several hours and no
birds sit or poop on it. (Good luck HDR Skycam ! )

I have zipped all the files used to make the video and put them on the page
for download, as well as a few experiments i have made in manipulating
surfaces (either transmission or shading) in response to sky data from
Portland, Oregon using a Canon A570 with Stereo Data Maker used to automate
bracketed image acquisition (i have a plan to post the details for that, as
it is a very low-cost < $80 approach and will get to it).

let me know (offline) if there are issues downloading or executing the
files,

best,

-Kyle

···

-----------------------------------------------
Kyle Konis, AIA, Ph.D
Assistant Professor
School of Architecture, WAH 204
University of Southern California
Los Angeles, CA 90089-0291
http://arch.usc.edu/faculty/kkonis
-----------------------------------------------

On Tue, Jul 1, 2014 at 8:52 AM, Christian Humann <chris@christianhumann.com> wrote:

Hi Joe,

Thank you for the references.

The HDR image by default is co-planar with the x and z axis with its
surface normal pointing in the negative y direction. You'll need to
translate the image so that its surface normal is pointed down along the
negative z axis and rotate it so that North is up when looking up towards
zenith.

The groundglow description is actually not necessary and has no effect. If
you wanted to define the ground for inclusion in a scene you could use the
following:

void glow groundglow
0
0
4 .15 .15 .15 0 #(.15 .15 .15 = RGB values for the ground material)

groundglow source ground
0
0
4 0 0 -1 180

I too have been getting lower values than the measured global horizontal
illuminance. I think the suggestions made made by Rob and Greg about using
mksource and adjusting the subtended angle of the solar source may be the
solution. Not sure yet how to implement the latter but I will certainly
keep you posted.

Cheers,
Chris

On Jun 30, 2014, at 10:26 PM, Joe Smith <the.oat.cracker@gmail.com> wrote:

Hi Chris,

Thank you very much for your reply, especially for reminding me the
conversion of the unit between foot candela and lux!

May I ask the following questions?

1. why the hdr fisheye image needs to be rotated along x axis for 90
degrees and along z axis for 180 degrees? using the fisheye.cal file as
reference when defining the colorpict "skypict"?

2. why "skypict is used as a modifier to define the "glow" material
"groundglow"? I thought usually this position is set as "void"

Using your approach, I tried some other hdr image provided by your
project, and it seems the global horizontal illuminance is always
underestimated as compared to the one reported in the csv file.

rubbing my head about this issue, and advices are greatly appreciated!

Regards,
Joe

On Tue, Jul 1, 2014 at 3:06 AM, Christian Humann < > chris@christianhumann.com> wrote:

Hi Joe,

The global values in the CSV file are in footcandles so you will need to
multiply them by 10.76 in order to get Lux.

Also, you'll need to add a source description for the sun in order to get
the solar contribution as the camera sensor can not capture the intensity
of the sun for the HDR image. Essentially the HDR image allows you to get
a close approximation of the global diffuse value. I use gendaylit (see
below) to generate the sun and sky scene. You can get the altitude,
azimuth, direct-normal-illuminance and diffuse-horizontal-illuminance from
the CSV file (be sure to multiply the latter two values by 10.76 to
translate them from footcandles to Lux for input into Gendaylit). Also be
sure to adjust your 'rtrace' results by dividing by 10.76 to get
footcandles if you want to compare to the global-horizontal-illuminacne
readings in the CSV file.

########Sun and Sky scene -----> global.rad
!gendaylit -ang 45.41 85.92 -w -O 0 -L 80463.28 19916.76 | xform -e -rz
0
void colorpict skypict
11 red green blue 140621_1530.hdr fisheye.cal fish_u fish_v -rx 90 -rz 180
0
0

skypict glow skyglow
0
0
4 1 1 1 1

skyglow source sky
0
0
4 0 0 1 180

skypict glow groundglow
0
0
4 1 1 1 0

groundglow source ground
0
0
4 0 0 -1 180
#########
# 3. the cmd.sh file
oconv ./global.rad > ./scene_empty.oct

echo '0 0 0 0 0 1' | rtrace -I -h -w -ab 1 -oov ./scene_empty.oct >
./results_position_irradiance_RGB_wm2.txt

cat ./results_position_irradiance_RGB_wm2.txt | rcalc -e
'$1=179*(0.265*$4+0.670*$5+0.065*$6)/10.76' > ./results_illuminance_lux.txt
##########

When I run the above I get a global horizontal illuminance value from
'rtrace' of approx. 6900 footcandles. The photometer gave a reading of
7176 footcandles.

I'm still working my brain around all this as well and hope that these
discussions will foster a better understanding of how to use the HDR images
for the highest level of accuracy possible.

Hope this helps.

Best,
Chris

On Jun 28, 2014, at 10:06 AM, Joe Smith <the.oat.cracker@gmail.com> >> wrote:

Hi, I found 2 references and did a test to generate HDR image-based
rendering, steps are explained below.

But I'm still rubbing my head to understand how the Cartesian coordinates
or the postion vector of a point on the sky is transformed as UV
coordinates of the fisheye image as shown in the "angmap.cal" file. So,
advices are greatly appreciated!

Thanks!
Joe

References:
1. Debevec, P. (2002). Image-based lighting. IEEE Computer Graphics and
Applications, 22(2), 26-34. doi: 10.1109/38.988744
2. Au, P. Y. P. (2013). HDR Luminance Measurement: Comparing real and
simulated data. (Master of Building Science Thesis), Victoria University of
Wellington.

Steps:
Step1. prepare the following 6 files and put them in the same folder

#### 1.1 geom.rad ################################################
red_plastic sphere ball
0
0
4 2 2 0.5 0.5

steel sphere ball1
0
0
4 2 -2 0.5 0.5

gold sphere ball2
0
0
4 -2 -2 0.5 0.5

white_matte sphere ball3
0
0
4 -2 2 0.5 0.5

crystal sphere ball4
0
0
4 0 0 1 1

!genbox gray_plastic pedestal_top 8 8 0.5 | xform -t -4 -4 -0.5

#### 1.2 materials.mat ################################################
void plastic red_plastic
0
0
5 .7 .1 .1 .06 .1

void metal steel
0
0
5 0.6 0.62 0.68 1 0

void metal gold
0
0
5 0.75 0.55 0.25 0.85 0.2

void plastic white_matte
0
0
5 .8 .8 .8 0 0

void dielectric crystal
0
0
5 .5 .5 .5 1.5 0

void plastic black_matte
0
0
5 .02 .02 .02 .00 .00

void plastic gray_plastic
0
0
5 0.25 0.25 0.25 0.06 0.0

#### 1.3 sky_and_ground.rad
################################################
void colorpict hdr_image
7 red green blue 140621_1530.hdr angmap.cal u v
0
0

hdr_image glow sky_glow
0
0
4 1 1 1 0

sky_glow source HDR_sky
0
0
4 0 0 1 180

# ground
void glow ground_glow
0
0
4 1 1 1 0

ground_glow source ground
0
0
4 0 0 -1 180

#### 1.4 angmap.cal ################################################
{
angmap.cal

Convert from directions in the world (Dx, Dy, Dz) into (u,v)
coordinates on the light probe image

+z is up (toward top of sphere, i.e. the zenith)
+y is North
}

d = sqrt(Dx*Dx + Dy*Dy);

r = acos(Dz)/PI;

u = 0.5 - Dx/d * r;
v = 0.5 + Dy/d * r;

#### 1.5 view.vf ################################################
# looking towards east
#rvu -vtv -vp -12 0 0.5 -vd 1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards west
#rvu -vtv -vp 12 0 0.5 -vd -1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards north
rvu -vtv -vp 0 -12 0.5 -vd 0 1 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards south
#rvu -vtv -vp 0 12 0.5 -vd 0 -1 0 -vu 0 0 1 -vh 60 -vv 40

#### 1.6 cmd.sh ################################################
oconv ./materials.mat ./sky_and_ground.rad ./geom.rad > ./scene.oct

rvu -vf ./view.vf ./scene.oct

#ximage ./sky.hdr

rpict -x 2400 -y 2400 -t 30 -ab 1 -ar 50000 -aa 0.08 -ad 128 -as 64 -st 0
-lw 0 -lr 8 -vf ./view.vf ./scene.oct > ./image.hdr

pfilt -1 -x /3 -y /3 -r 1 ./image.hdr > ./image_filtered.hdr

Step2. put the 140621_1530.hdr file provided by LBNL (
http://flexskycam.lbl.gov) in the same folder

Step3. run the cmd.sh batch file to produce the rendering

On Sat, Jun 28, 2014 at 7:28 AM, Andrew McNeil <amcneil@lbl.gov> wrote:

Hi All,

I haven't done any testing myself, I wanted to make the data available
right away so that others could tinker too (and maybe make it easier for
me).

Joe - You're correct that the HDR sky image essentially replaces the
skyfunc modifier, here's a thread where Kyle was doing the same thing:
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008962.html

Rob - In a clear sky condition our HDR images won't capture the full
luminance of the sun. Mksource would be helpful to zero out the pixels, but
the source that it makes won't be useful without adjusting the radiance of
the source to match that of the sun.

Best,
Andy

On Fri, Jun 27, 2014 at 2:58 PM, Rob Guglielmetti < >>> rob.guglielmetti@gmail.com> wrote:

Hi German, and everyone else. Certainly one could use these HDR images
to generate sky vectors and apply them to daylight coefficients for a given
model(s). Greg Ward has created a cool tool called mksource to facilitate
this process in Radiance, identifying small, intense pixels in the image;
creating and placing Radiance light sources in their stead, and zeroing the
pixels to avoid double counting.

Considerations:
- Capturing the true (full) dynamic range of an exterior scene with
direct sun is difficult.
- Using locally-captured HDR images for daylight availability analysis
is statistically dubious. Granted, so is using TMY data, for different
reasons. This is why I changed the title of this list to "considerations",
from "problems". =)

On Fri, Jun 27, 2014 at 3:38 PM, CHI-German Molina <gmolina@hdlao.com> >>>> wrote:

Wow, I have been thinking on doing this for a while... although I have
no idea where to start from.

Is it possible to calculate the Daylight Coefficients of the building;
and use the HDR image to generate sky vectors and calculate different
options for optimizing daylighting?

I am picturing a computer that, every 5 minutes, calculate the sky
vector, computes the interior lighting conditions, and simulates the
different lighting options performing a whole-building lighting control
with no photo sensors. Even more, maybe a whole neighborhood could use the
same camera. Nonsense?

Thanks for sharing!

2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker@gmail.com>:

Hi, Andy, thanks for sharing LBNL's sky mapping experiment!

Can you kindly advice on resources that elaborate on how to use HDR
sky image for daylight simulation? Does it involve specifying the HDR
image, rather than a "skyfunc", as the material identifier for the sky
geometry? How is the pixel value of a given point on the HDR image
converted to luminance value of the corresponding position on the sky?

Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov>于2014年6月27日星期五写道：

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site:
http://flexskycam.lbl.gov. I've uploaded sample data, including hdr
images and csv datafiles, recorded by the camera for three days over the
past week( clear, partly cloudy and overcast). We're happy to share more
data with other researchers and daylight practitioners (but we don't have
much to offer yet).

The images can be mapped to a Radiance sky for simulation under real
sky conditions. I have not used the sky HDR images yet, myself, so if
anybody uses them successfully please report back and share what you've
done!

Questions about the camera hardware and capabilities should be
directed to Chris Humann at Terrestrial Light.

Best,
Andy

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
*Germán Molina L.*
Ingeniero Trainee
Hunter Douglas Chile S.A.
Celular +569 89224445

*Nota de Confidencialidad:* Este mensaje incluído los archivos
adjuntos son confidenciales y pueden contener informacion privilegiada
protegida por ley. Si Ud. no es el destinatario, deberia abstenerse de
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que la compania puede hacer un seguimiento de sus mensajes electronicos y
su contenido, gracias.

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message, including any attachment, is confidential and is intended only for
the person or entity to which it is addressed. If you are neither the
intended recipient nor the employee or agent responsible for delivering
this message to the intended recipient, you are hereby notified that you
may not review, retransmit, convert to hard copy, copy, use or distribute
this email message or any attachments to it. If you have received this
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Joe_Smith · July 10, 2014, 11:39am

Dear Chris and the list,

May I ask if the "*fisheye.cal*" file come with Radiance installation only
works with fisheye image took/generated by *angular projection *which is
used by most of the fisheye lens?

Suppose I want to use the HDR fisheye image (for example, a sunny sky
defined by gensky's "+s" option) generated from RPICT as input for
"colorpict", following the approach you explained, I need to use the "-vta"
option for RPICT, is it?

If it is the case, how to create our own .cal file to map fisheye image
using hemispherical (-vth) or stereographic (-vts) projection?

Thank you!
Joe

···

On Tue, Jul 1, 2014 at 11:52 PM, Christian Humann <chris@christianhumann.com > wrote:

Hi Joe,

Thank you for the references.

The HDR image by default is co-planar with the x and z axis with its
surface normal pointing in the negative y direction. You'll need to
translate the image so that its surface normal is pointed down along the
negative z axis and rotate it so that North is up when looking up towards
zenith.

The groundglow description is actually not necessary and has no effect. If
you wanted to define the ground for inclusion in a scene you could use the
following:

void glow groundglow
0
0
4 .15 .15 .15 0 #(.15 .15 .15 = RGB values for the ground material)

groundglow source ground
0
0
4 0 0 -1 180

I too have been getting lower values than the measured global horizontal
illuminance. I think the suggestions made made by Rob and Greg about using
mksource and adjusting the subtended angle of the solar source may be the
solution. Not sure yet how to implement the latter but I will certainly
keep you posted.

Cheers,
Chris

On Jun 30, 2014, at 10:26 PM, Joe Smith <the.oat.cracker@gmail.com> wrote:

Hi Chris,

Thank you very much for your reply, especially for reminding me the
conversion of the unit between foot candela and lux!

May I ask the following questions?

1. why the hdr fisheye image needs to be rotated along x axis for 90
degrees and along z axis for 180 degrees? using the fisheye.cal file as
reference when defining the colorpict "skypict"?

2. why "skypict is used as a modifier to define the "glow" material
"groundglow"? I thought usually this position is set as "void"

Using your approach, I tried some other hdr image provided by your
project, and it seems the global horizontal illuminance is always
underestimated as compared to the one reported in the csv file.

rubbing my head about this issue, and advices are greatly appreciated!

Regards,
Joe

On Tue, Jul 1, 2014 at 3:06 AM, Christian Humann < > chris@christianhumann.com> wrote:

Hi Joe,

The global values in the CSV file are in footcandles so you will need to
multiply them by 10.76 in order to get Lux.

Also, you'll need to add a source description for the sun in order to get
the solar contribution as the camera sensor can not capture the intensity
of the sun for the HDR image. Essentially the HDR image allows you to get
a close approximation of the global diffuse value. I use gendaylit (see
below) to generate the sun and sky scene. You can get the altitude,
azimuth, direct-normal-illuminance and diffuse-horizontal-illuminance from
the CSV file (be sure to multiply the latter two values by 10.76 to
translate them from footcandles to Lux for input into Gendaylit). Also be
sure to adjust your 'rtrace' results by dividing by 10.76 to get
footcandles if you want to compare to the global-horizontal-illuminacne
readings in the CSV file.

########Sun and Sky scene -----> global.rad
!gendaylit -ang 45.41 85.92 -w -O 0 -L 80463.28 19916.76 | xform -e -rz
0
void colorpict skypict
11 red green blue 140621_1530.hdr fisheye.cal fish_u fish_v -rx 90 -rz 180
0
0

skypict glow skyglow
0
0
4 1 1 1 1

skyglow source sky
0
0
4 0 0 1 180

skypict glow groundglow
0
0
4 1 1 1 0

groundglow source ground
0
0
4 0 0 -1 180
#########
# 3. the cmd.sh file
oconv ./global.rad > ./scene_empty.oct

echo '0 0 0 0 0 1' | rtrace -I -h -w -ab 1 -oov ./scene_empty.oct >
./results_position_irradiance_RGB_wm2.txt

cat ./results_position_irradiance_RGB_wm2.txt | rcalc -e
'$1=179*(0.265*$4+0.670*$5+0.065*$6)/10.76' > ./results_illuminance_lux.txt
##########

When I run the above I get a global horizontal illuminance value from
'rtrace' of approx. 6900 footcandles. The photometer gave a reading of
7176 footcandles.

I'm still working my brain around all this as well and hope that these
discussions will foster a better understanding of how to use the HDR images
for the highest level of accuracy possible.

Hope this helps.

Best,
Chris

On Jun 28, 2014, at 10:06 AM, Joe Smith <the.oat.cracker@gmail.com> >> wrote:

Hi, I found 2 references and did a test to generate HDR image-based
rendering, steps are explained below.

But I'm still rubbing my head to understand how the Cartesian coordinates
or the postion vector of a point on the sky is transformed as UV
coordinates of the fisheye image as shown in the "angmap.cal" file. So,
advices are greatly appreciated!

Thanks!
Joe

References:
1. Debevec, P. (2002). Image-based lighting. IEEE Computer Graphics and
Applications, 22(2), 26-34. doi: 10.1109/38.988744
2. Au, P. Y. P. (2013). HDR Luminance Measurement: Comparing real and
simulated data. (Master of Building Science Thesis), Victoria University of
Wellington.

Steps:
Step1. prepare the following 6 files and put them in the same folder

#### 1.1 geom.rad ################################################
red_plastic sphere ball
0
0
4 2 2 0.5 0.5

steel sphere ball1
0
0
4 2 -2 0.5 0.5

gold sphere ball2
0
0
4 -2 -2 0.5 0.5

white_matte sphere ball3
0
0
4 -2 2 0.5 0.5

crystal sphere ball4
0
0
4 0 0 1 1

!genbox gray_plastic pedestal_top 8 8 0.5 | xform -t -4 -4 -0.5

#### 1.2 materials.mat ################################################
void plastic red_plastic
0
0
5 .7 .1 .1 .06 .1

void metal steel
0
0
5 0.6 0.62 0.68 1 0

void metal gold
0
0
5 0.75 0.55 0.25 0.85 0.2

void plastic white_matte
0
0
5 .8 .8 .8 0 0

void dielectric crystal
0
0
5 .5 .5 .5 1.5 0

void plastic black_matte
0
0
5 .02 .02 .02 .00 .00

void plastic gray_plastic
0
0
5 0.25 0.25 0.25 0.06 0.0

#### 1.3 sky_and_ground.rad
################################################
void colorpict hdr_image
7 red green blue 140621_1530.hdr angmap.cal u v
0
0

hdr_image glow sky_glow
0
0
4 1 1 1 0

sky_glow source HDR_sky
0
0
4 0 0 1 180

# ground
void glow ground_glow
0
0
4 1 1 1 0

ground_glow source ground
0
0
4 0 0 -1 180

#### 1.4 angmap.cal ################################################
{
angmap.cal

Convert from directions in the world (Dx, Dy, Dz) into (u,v)
coordinates on the light probe image

+z is up (toward top of sphere, i.e. the zenith)
+y is North
}

d = sqrt(Dx*Dx + Dy*Dy);

r = acos(Dz)/PI;

u = 0.5 - Dx/d * r;
v = 0.5 + Dy/d * r;

#### 1.5 view.vf ################################################
# looking towards east
#rvu -vtv -vp -12 0 0.5 -vd 1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards west
#rvu -vtv -vp 12 0 0.5 -vd -1 0 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards north
rvu -vtv -vp 0 -12 0.5 -vd 0 1 0 -vu 0 0 1 -vh 60 -vv 40
# looking towards south
#rvu -vtv -vp 0 12 0.5 -vd 0 -1 0 -vu 0 0 1 -vh 60 -vv 40

#### 1.6 cmd.sh ################################################
oconv ./materials.mat ./sky_and_ground.rad ./geom.rad > ./scene.oct

rvu -vf ./view.vf ./scene.oct

#ximage ./sky.hdr

rpict -x 2400 -y 2400 -t 30 -ab 1 -ar 50000 -aa 0.08 -ad 128 -as 64 -st 0
-lw 0 -lr 8 -vf ./view.vf ./scene.oct > ./image.hdr

pfilt -1 -x /3 -y /3 -r 1 ./image.hdr > ./image_filtered.hdr

Step2. put the 140621_1530.hdr file provided by LBNL (
http://flexskycam.lbl.gov) in the same folder

Step3. run the cmd.sh batch file to produce the rendering

On Sat, Jun 28, 2014 at 7:28 AM, Andrew McNeil <amcneil@lbl.gov> wrote:

Hi All,

I haven't done any testing myself, I wanted to make the data available
right away so that others could tinker too (and maybe make it easier for
me).

Joe - You're correct that the HDR sky image essentially replaces the
skyfunc modifier, here's a thread where Kyle was doing the same thing:
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008962.html

Rob - In a clear sky condition our HDR images won't capture the full
luminance of the sun. Mksource would be helpful to zero out the pixels, but
the source that it makes won't be useful without adjusting the radiance of
the source to match that of the sun.

Best,
Andy

On Fri, Jun 27, 2014 at 2:58 PM, Rob Guglielmetti < >>> rob.guglielmetti@gmail.com> wrote:

Hi German, and everyone else. Certainly one could use these HDR images
to generate sky vectors and apply them to daylight coefficients for a given
model(s). Greg Ward has created a cool tool called mksource to facilitate
this process in Radiance, identifying small, intense pixels in the image;
creating and placing Radiance light sources in their stead, and zeroing the
pixels to avoid double counting.

Considerations:
- Capturing the true (full) dynamic range of an exterior scene with
direct sun is difficult.
- Using locally-captured HDR images for daylight availability analysis
is statistically dubious. Granted, so is using TMY data, for different
reasons. This is why I changed the title of this list to "considerations",
from "problems". =)

On Fri, Jun 27, 2014 at 3:38 PM, CHI-German Molina <gmolina@hdlao.com> >>>> wrote:

Wow, I have been thinking on doing this for a while... although I have
no idea where to start from.

Is it possible to calculate the Daylight Coefficients of the building;
and use the HDR image to generate sky vectors and calculate different
options for optimizing daylighting?

I am picturing a computer that, every 5 minutes, calculate the sky
vector, computes the interior lighting conditions, and simulates the
different lighting options performing a whole-building lighting control
with no photo sensors. Even more, maybe a whole neighborhood could use the
same camera. Nonsense?

Thanks for sharing!

2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker@gmail.com>:

Hi, Andy, thanks for sharing LBNL's sky mapping experiment!

Can you kindly advice on resources that elaborate on how to use HDR
sky image for daylight simulation? Does it involve specifying the HDR
image, rather than a "skyfunc", as the material identifier for the sky
geometry? How is the pixel value of a given point on the HDR image
converted to luminance value of the corresponding position on the sky?

Thanks!
- Joe

Andrew McNeil <amcneil@lbl.gov>于2014年6月27日星期五写道：

Hi Everyone,

LBNL has installed an HDR sky camera at our new FLEXLAB site:
http://flexskycam.lbl.gov. I've uploaded sample data, including hdr
images and csv datafiles, recorded by the camera for three days over the
past week( clear, partly cloudy and overcast). We're happy to share more
data with other researchers and daylight practitioners (but we don't have
much to offer yet).

The images can be mapped to a Radiance sky for simulation under real
sky conditions. I have not used the sky HDR images yet, myself, so if
anybody uses them successfully please report back and share what you've
done!

Questions about the camera hardware and capabilities should be
directed to Chris Humann at Terrestrial Light.

Best,
Andy

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
*Germán Molina L.*
Ingeniero Trainee
Hunter Douglas Chile S.A.
Celular +569 89224445

*Nota de Confidencialidad:* Este mensaje incluído los archivos
adjuntos son confidenciales y pueden contener informacion privilegiada
protegida por ley. Si Ud. no es el destinatario, deberia abstenerse de
copiarlo, distribuirlo, divulgarlo o usar la informacion contenida. Por
favor, avise inmediatamente al emisor y borre este mensaje de su sistema.
Los mensajes electronicos son susceptibles de ser cambiados, infectados o
adulterados sin autorizacion. No asumimos responsabilidad alguna por
ninguna clase de cambios o sus consecuencias. Usted debe estar informado
que la compania puede hacer un seguimiento de sus mensajes electronicos y
su contenido, gracias.

*Confidentiality Notice:* The information contained in this email
message, including any attachment, is confidential and is intended only for
the person or entity to which it is addressed. If you are neither the
intended recipient nor the employee or agent responsible for delivering
this message to the intended recipient, you are hereby notified that you
may not review, retransmit, convert to hard copy, copy, use or distribute
this email message or any attachments to it. If you have received this
email in error, please contact the sender immediately and delete this
message from any computer or other data bank, Thank you.

A informação transmitida é confidencial e para conhecimento exclusivo
do destinatário. Sua utilização, não autorizada, constitui crime passível
de prisão. Todas as precauções possíveis foram tomadas para garantir que
este e-mail não contenha vírus. Uma vez que nossa empresa não pode assumir
responsabilidade por nenhuma perda ou dano causado por este e-mail ou de
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Greg_Ward · July 10, 2014, 4:17pm

Hi Joe,

Do you really need to do this? The code for view angle calculations is not very straightforward, but if you are really motivated, you can convert the C code in the viewloc() routine found in src/common/image.c to the .cal language.

Cheers,
-Greg

···

From: Joe Smith <the.oat.cracker@gmail.com>
Subject: Re: [Radiance-general] HDR Sky Camera @ LBNL's Flexlab
Date: July 10, 2014 4:39:04 AM PDT

Dear Chris and the list,

May I ask if the "fisheye.cal" file come with Radiance installation only works with fisheye image took/generated by angular projection which is used by most of the fisheye lens?

Suppose I want to use the HDR fisheye image (for example, a sunny sky defined by gensky's "+s" option) generated from RPICT as input for "colorpict", following the approach you explained, I need to use the "-vta" option for RPICT, is it?

If it is the case, how to create our own .cal file to map fisheye image using hemispherical (-vth) or stereographic (-vts) projection?

Thank you!
Joe

On Tue, Jul 1, 2014 at 11:52 PM, Christian Humann <chris@christianhumann.com> wrote: