BSDF question

radiance-general
1

Dear all,

I am working with the 3 phase method (only from a few weeks) and I am
trying to understand the BSDF file format and how the 3 phase method read
it.

I have noticed that if I use the bsdf created with the command:
genBSDF -n 4 +f +b -geom meter material.rad blinds.rad > blinds.xml
the .xml file contain same geometrical dimension (height, width). In fact
if I use the command:
pkgBSDF -s blinds.xml > blinds_pkg.rad
the output file contain the original geometry.

Instead if I use the BSDF created or contained in the database of WINDOW 7
these file do not contain a geometry.
With pkgBSDF I got an error.

My questions are:
1. in the equation i=VTDs the T matrix has to contain the window geometry
or take knowledge of these from the other two matrix(V,D)?
2. I have understood that 3 phase method uses only the front transmission
data [A. McNeil, Three-Phase Method tutorial] but in
an other discussion [
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008969.html
] I have discovered that WINDOW and genBSDF use an opposite meaning of
front and back, so the front transmission regards radiance or window
meaning?And what part of the T matrix I have to use in the 3 phase method
for the respective cases (WINDOW or genBSDF)?

Kind regards,
*Giuseppe*

2

Guiseppe,

The three-phase method simulation method does not use the geometry of the
shading device to work. In fact, one advantage of it is that only the
BSDF.xml file is needed. If you check Andy's Three-phase method tutorial,
you will see that the calculation of the V and D matrices do not require
neither the geometry of the shading device nor the BSDF of it (thus making
it very easy to try multiple fenestration systems).

Adding Geometry information to the BSDF file is useful for using pkgBSDF;
not really for the 3phase method. When rays have to go through the
fenestration system (i.e. rendering a room with venetian blinds, or when
calculating the third matrix of the 5 phase method) a combination of two
illums that "wrap" the geometry and the geometry itself seems to be more
efficient. My understanding (I might be completely wrong) is that the
illums are used to transfer the diffuse (indirect??) radiation; and the
geometry is used for transfering direct radiation, casting shadows.

My answer to the first question:

*1. in the equation i=VTDs the T matrix has to contain the window geometry
or take knowledge of these from the other two matrix(V,D)? *

Nope. After the V and D matrices are calculated, the simulation is
performed by simply multiplying matrices... no geometry.

The second question is something that confuses me... it would be good to
have clarification here.

Hope this helps!

Germán

···

2014-07-02 11:54 GMT-04:00 Giuseppe De Michele <[email protected]>:

Dear all,

I am working with the 3 phase method (only from a few weeks) and I am
trying to understand the BSDF file format and how the 3 phase method read
it.

I have noticed that if I use the bsdf created with the command:
genBSDF -n 4 +f +b -geom meter material.rad blinds.rad > blinds.xml
the .xml file contain same geometrical dimension (height, width). In fact
if I use the command:
pkgBSDF -s blinds.xml > blinds_pkg.rad
the output file contain the original geometry.

Instead if I use the BSDF created or contained in the database of WINDOW
7 these file do not contain a geometry.
With pkgBSDF I got an error.

My questions are:
1. in the equation i=VTDs the T matrix has to contain the window geometry
or take knowledge of these from the other two matrix(V,D)?
2. I have understood that 3 phase method uses only the front transmission
data [A. McNeil, Three-Phase Method tutorial] but in
an other discussion [
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008969.html
] I have discovered that WINDOW and genBSDF use an opposite meaning of
front and back, so the front transmission regards radiance or window
meaning?And what part of the T matrix I have to use in the 3 phase method
for the respective cases (WINDOW or genBSDF)?

Kind regards,
*Giuseppe*

_______________________________________________
Radiance-general mailing list
[email protected]
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.

3

Giuseppe,

The front/back inconsistency is mostly related to the BSDF material
primitive. For the 3-phase method you don't have to worry about front/back
of the fenestration. (unless you want to use a BSDF backwards, which might
be impossible without manually editing the BSDF file).

The BSDF handling has matured quite a bit since the early days of the
three-phase method. These days dctimestep can use either front transmission
or back transmission applying reciprocity principles for the three phase
method.

Andy

···

On Wed, Jul 2, 2014 at 9:24 AM, CHI-German Molina <[email protected]> wrote:

Guiseppe,

The three-phase method simulation method does not use the geometry of the
shading device to work. In fact, one advantage of it is that only the
BSDF.xml file is needed. If you check Andy's Three-phase method tutorial,
you will see that the calculation of the V and D matrices do not require
neither the geometry of the shading device nor the BSDF of it (thus making
it very easy to try multiple fenestration systems).

Adding Geometry information to the BSDF file is useful for using pkgBSDF;
not really for the 3phase method. When rays have to go through the
fenestration system (i.e. rendering a room with venetian blinds, or when
calculating the third matrix of the 5 phase method) a combination of two
illums that "wrap" the geometry and the geometry itself seems to be more
efficient. My understanding (I might be completely wrong) is that the
illums are used to transfer the diffuse (indirect??) radiation; and the
geometry is used for transfering direct radiation, casting shadows.

My answer to the first question:

*1. in the equation i=VTDs the T matrix has to contain the window
geometry or take knowledge of these from the other two matrix(V,D)? *

Nope. After the V and D matrices are calculated, the simulation is
performed by simply multiplying matrices... no geometry.

The second question is something that confuses me... it would be good to
have clarification here.

Hope this helps!

Germán

2014-07-02 11:54 GMT-04:00 Giuseppe De Michele <[email protected]>:

Dear all,

I am working with the 3 phase method (only from a few weeks) and I am
trying to understand the BSDF file format and how the 3 phase method read
it.

I have noticed that if I use the bsdf created with the command:
genBSDF -n 4 +f +b -geom meter material.rad blinds.rad > blinds.xml
the .xml file contain same geometrical dimension (height, width). In fact
if I use the command:
pkgBSDF -s blinds.xml > blinds_pkg.rad
the output file contain the original geometry.

Instead if I use the BSDF created or contained in the database of WINDOW
7 these file do not contain a geometry.
With pkgBSDF I got an error.

My questions are:
1. in the equation i=VTDs the T matrix has to contain the window
geometry or take knowledge of these from the other two matrix(V,D)?
2. I have understood that 3 phase method uses only the front
transmission data [A. McNeil, Three-Phase Method tutorial] but in
an other discussion [
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008969.html
] I have discovered that WINDOW and genBSDF use an opposite meaning of
front and back, so the front transmission regards radiance or window
meaning?And what part of the T matrix I have to use in the 3 phase method
for the respective cases (WINDOW or genBSDF)?

Kind regards,
*Giuseppe*

_______________________________________________
Radiance-general mailing list
[email protected]
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
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

4

Germán and Andy,

meanwhile thank you for the answers and sorry if my questions are a little
bit confused. I am a newbie of the "lighting art" and I am studying this
concepts almost alone.
So if I understood, when I create a BSDF matrix with genBSDF I add the +f
+b options in order to obtain both transmission matrix and then dctimestep
does the rest, doesn't it?

Thanks for yours great help,
Giuseppe

···

2014-07-02 19:12 GMT+02:00 Andrew McNeil <[email protected]>:

Giuseppe,

The front/back inconsistency is mostly related to the BSDF material
primitive. For the 3-phase method you don't have to worry about front/back
of the fenestration. (unless you want to use a BSDF backwards, which might
be impossible without manually editing the BSDF file).

The BSDF handling has matured quite a bit since the early days of the
three-phase method. These days dctimestep can use either front transmission
or back transmission applying reciprocity principles for the three phase
method.

Andy

On Wed, Jul 2, 2014 at 9:24 AM, CHI-German Molina <[email protected]> > wrote:

Guiseppe,

The three-phase method simulation method does not use the geometry of the
shading device to work. In fact, one advantage of it is that only the
BSDF.xml file is needed. If you check Andy's Three-phase method tutorial,
you will see that the calculation of the V and D matrices do not require
neither the geometry of the shading device nor the BSDF of it (thus making
it very easy to try multiple fenestration systems).

Adding Geometry information to the BSDF file is useful for using pkgBSDF;
not really for the 3phase method. When rays have to go through the
fenestration system (i.e. rendering a room with venetian blinds, or when
calculating the third matrix of the 5 phase method) a combination of two
illums that "wrap" the geometry and the geometry itself seems to be more
efficient. My understanding (I might be completely wrong) is that the
illums are used to transfer the diffuse (indirect??) radiation; and the
geometry is used for transfering direct radiation, casting shadows.

My answer to the first question:

*1. in the equation i=VTDs the T matrix has to contain the window
geometry or take knowledge of these from the other two matrix(V,D)? *

Nope. After the V and D matrices are calculated, the simulation is
performed by simply multiplying matrices... no geometry.

The second question is something that confuses me... it would be good to
have clarification here.

Hope this helps!

Germán

2014-07-02 11:54 GMT-04:00 Giuseppe De Michele <[email protected]>:

Dear all,

I am working with the 3 phase method (only from a few weeks) and I am
trying to understand the BSDF file format and how the 3 phase method read
it.

I have noticed that if I use the bsdf created with the command:
genBSDF -n 4 +f +b -geom meter material.rad blinds.rad > blinds.xml
the .xml file contain same geometrical dimension (height, width). In
fact if I use the command:
pkgBSDF -s blinds.xml > blinds_pkg.rad
the output file contain the original geometry.

Instead if I use the BSDF created or contained in the database of
WINDOW 7 these file do not contain a geometry.
With pkgBSDF I got an error.

My questions are:
1. in the equation i=VTDs the T matrix has to contain the window
geometry or take knowledge of these from the other two matrix(V,D)?
2. I have understood that 3 phase method uses only the front
transmission data [A. McNeil, Three-Phase Method tutorial] but in
an other discussion [
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008969.html
] I have discovered that WINDOW and genBSDF use an opposite meaning of
front and back, so the front transmission regards radiance or window
meaning?And what part of the T matrix I have to use in the 3 phase method
for the respective cases (WINDOW or genBSDF)?

Kind regards,
*Giuseppe*

_______________________________________________
Radiance-general mailing list
[email protected]
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
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
*Giuseppe De Michele*

5

Hi Giuseppe,

You only really need either +f or +b, not both. genBSDF does +b by default
so if you only wanted to do the forward direction you should use +f -b.
Doing one direction takes about half as much time as doing both directions.
However, if you want to import into Window you'll need to do both
directions.

Andy

···

On Thu, Jul 3, 2014 at 12:45 AM, Giuseppe De Michele <[email protected]> wrote:

Germán and Andy,

meanwhile thank you for the answers and sorry if my questions are a little
bit confused. I am a newbie of the "lighting art" and I am studying this
concepts almost alone.
So if I understood, when I create a BSDF matrix with genBSDF I add the +f
+b options in order to obtain both transmission matrix and then dctimestep
does the rest, doesn't it?

Thanks for yours great help,
Giuseppe

2014-07-02 19:12 GMT+02:00 Andrew McNeil <[email protected]>:

Giuseppe,

The front/back inconsistency is mostly related to the BSDF material
primitive. For the 3-phase method you don't have to worry about front/back
of the fenestration. (unless you want to use a BSDF backwards, which might
be impossible without manually editing the BSDF file).

The BSDF handling has matured quite a bit since the early days of the
three-phase method. These days dctimestep can use either front transmission
or back transmission applying reciprocity principles for the three phase
method.

Andy

On Wed, Jul 2, 2014 at 9:24 AM, CHI-German Molina <[email protected]> >> wrote:

Guiseppe,

The three-phase method simulation method does not use the geometry of
the shading device to work. In fact, one advantage of it is that only the
BSDF.xml file is needed. If you check Andy's Three-phase method tutorial,
you will see that the calculation of the V and D matrices do not require
neither the geometry of the shading device nor the BSDF of it (thus making
it very easy to try multiple fenestration systems).

Adding Geometry information to the BSDF file is useful for using
pkgBSDF; not really for the 3phase method. When rays have to go through the
fenestration system (i.e. rendering a room with venetian blinds, or when
calculating the third matrix of the 5 phase method) a combination of two
illums that "wrap" the geometry and the geometry itself seems to be more
efficient. My understanding (I might be completely wrong) is that the
illums are used to transfer the diffuse (indirect??) radiation; and the
geometry is used for transfering direct radiation, casting shadows.

My answer to the first question:

*1. in the equation i=VTDs the T matrix has to contain the window
geometry or take knowledge of these from the other two matrix(V,D)? *

Nope. After the V and D matrices are calculated, the simulation is
performed by simply multiplying matrices... no geometry.

The second question is something that confuses me... it would be good to
have clarification here.

Hope this helps!

Germán

2014-07-02 11:54 GMT-04:00 Giuseppe De Michele <[email protected]>:

Dear all,

I am working with the 3 phase method (only from a few weeks) and I am
trying to understand the BSDF file format and how the 3 phase method read
it.

I have noticed that if I use the bsdf created with the command:
genBSDF -n 4 +f +b -geom meter material.rad blinds.rad > blinds.xml
the .xml file contain same geometrical dimension (height, width). In
fact if I use the command:
pkgBSDF -s blinds.xml > blinds_pkg.rad
the output file contain the original geometry.

Instead if I use the BSDF created or contained in the database of
WINDOW 7 these file do not contain a geometry.
With pkgBSDF I got an error.

My questions are:
1. in the equation i=VTDs the T matrix has to contain the window
geometry or take knowledge of these from the other two matrix(V,D)?
2. I have understood that 3 phase method uses only the front
transmission data [A. McNeil, Three-Phase Method tutorial] but in
an other discussion [
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008969.html
] I have discovered that WINDOW and genBSDF use an opposite meaning of
front and back, so the front transmission regards radiance or window
meaning?And what part of the T matrix I have to use in the 3 phase method
for the respective cases (WINDOW or genBSDF)?

Kind regards,
*Giuseppe*

_______________________________________________
Radiance-general mailing list
[email protected]
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
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
*Giuseppe De Michele*

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

6

Andy,

How about using BSDFs for ray-tracing calculations? Does it use reciprocity
as well? or should we calculate +b ?

Also, was I correct when I said that the BSDFd "Proxy Geometry" is only
used for ambient calculations, and the geometry for Direct?

THANKS!

German

···

2014-07-07 10:32 GMT-04:00 Andrew McNeil <[email protected]>:

Hi Giuseppe,

You only really need either +f or +b, not both. genBSDF does +b by
default so if you only wanted to do the forward direction you should use +f
-b. Doing one direction takes about half as much time as doing both
directions. However, if you want to import into Window you'll need to do
both directions.

Andy

On Thu, Jul 3, 2014 at 12:45 AM, Giuseppe De Michele <[email protected]> > wrote:

Germán and Andy,

meanwhile thank you for the answers and sorry if my questions are a
little bit confused. I am a newbie of the "lighting art" and I am studying
this concepts almost alone.
So if I understood, when I create a BSDF matrix with genBSDF I add the
+f +b options in order to obtain both transmission matrix and then
dctimestep does the rest, doesn't it?

Thanks for yours great help,
Giuseppe

2014-07-02 19:12 GMT+02:00 Andrew McNeil <[email protected]>:

Giuseppe,

The front/back inconsistency is mostly related to the BSDF material
primitive. For the 3-phase method you don't have to worry about front/back
of the fenestration. (unless you want to use a BSDF backwards, which might
be impossible without manually editing the BSDF file).

The BSDF handling has matured quite a bit since the early days of the
three-phase method. These days dctimestep can use either front transmission
or back transmission applying reciprocity principles for the three phase
method.

Andy

On Wed, Jul 2, 2014 at 9:24 AM, CHI-German Molina <[email protected]> >>> wrote:

Guiseppe,

The three-phase method simulation method does not use the geometry of
the shading device to work. In fact, one advantage of it is that only the
BSDF.xml file is needed. If you check Andy's Three-phase method tutorial,
you will see that the calculation of the V and D matrices do not require
neither the geometry of the shading device nor the BSDF of it (thus making
it very easy to try multiple fenestration systems).

Adding Geometry information to the BSDF file is useful for using
pkgBSDF; not really for the 3phase method. When rays have to go through the
fenestration system (i.e. rendering a room with venetian blinds, or when
calculating the third matrix of the 5 phase method) a combination of two
illums that "wrap" the geometry and the geometry itself seems to be more
efficient. My understanding (I might be completely wrong) is that the
illums are used to transfer the diffuse (indirect??) radiation; and the
geometry is used for transfering direct radiation, casting shadows.

My answer to the first question:

*1. in the equation i=VTDs the T matrix has to contain the window
geometry or take knowledge of these from the other two matrix(V,D)? *

Nope. After the V and D matrices are calculated, the simulation is
performed by simply multiplying matrices... no geometry.

The second question is something that confuses me... it would be good
to have clarification here.

Hope this helps!

Germán

2014-07-02 11:54 GMT-04:00 Giuseppe De Michele <[email protected]>:

Dear all,

I am working with the 3 phase method (only from a few weeks) and I am
trying to understand the BSDF file format and how the 3 phase method read
it.

I have noticed that if I use the bsdf created with the command:
genBSDF -n 4 +f +b -geom meter material.rad blinds.rad > blinds.xml
the .xml file contain same geometrical dimension (height, width). In
fact if I use the command:
pkgBSDF -s blinds.xml > blinds_pkg.rad
the output file contain the original geometry.

Instead if I use the BSDF created or contained in the database of
WINDOW 7 these file do not contain a geometry.
With pkgBSDF I got an error.

My questions are:
1. in the equation i=VTDs the T matrix has to contain the window
geometry or take knowledge of these from the other two matrix(V,D)?
2. I have understood that 3 phase method uses only the front
transmission data [A. McNeil, Three-Phase Method tutorial] but in
an other discussion [
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008969.html
] I have discovered that WINDOW and genBSDF use an opposite meaning of
front and back, so the front transmission regards radiance or window
meaning?And what part of the T matrix I have to use in the 3 phase method
for the respective cases (WINDOW or genBSDF)?

Kind regards,
*Giuseppe*

_______________________________________________
Radiance-general mailing list
[email protected]
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
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_______________________________________________
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_______________________________________________
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--
*Giuseppe De Michele*

_______________________________________________
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_______________________________________________
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[email protected]
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
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antivírus antes de qualquer uso.

7

Reciprocity works for every BSDF type in Radiance except isotropic tensor trees, so specify +f with the -t3 option if you want transmission to go both ways. Also, you need +f to get the reflected rays on the opposite side of the surface, so you may want it under some other circumstances as well.

The geometry (if present) is used for shadow calculation during the direct calculation and for viewing the system, while the BSDF is used for all other purposes.

Cheers,
-Greg

···

From: CHI-German Molina <[email protected]>
Subject: Re: [Radiance-general] BSDF question
Date: July 7, 2014 7:39:33 AM PDT

Andy,

How about using BSDFs for ray-tracing calculations? Does it use reciprocity as well? or should we calculate +b ?

Also, was I correct when I said that the BSDFd "Proxy Geometry" is only used for ambient calculations, and the geometry for Direct?

THANKS!

German

2014-07-07 10:32 GMT-04:00 Andrew McNeil <[email protected]>:
Hi Giuseppe,

You only really need either +f or +b, not both. genBSDF does +b by default so if you only wanted to do the forward direction you should use +f -b. Doing one direction takes about half as much time as doing both directions. However, if you want to import into Window you'll need to do both directions.

Andy

On Thu, Jul 3, 2014 at 12:45 AM, Giuseppe De Michele <[email protected]> wrote:
Germán and Andy,

meanwhile thank you for the answers and sorry if my questions are a little bit confused. I am a newbie of the "lighting art" and I am studying this concepts almost alone.
So if I understood, when I create a BSDF matrix with genBSDF I add the +f +b options in order to obtain both transmission matrix and then dctimestep does the rest, doesn't it?

Thanks for yours great help,
Giuseppe

2014-07-02 19:12 GMT+02:00 Andrew McNeil <[email protected]>:

Giuseppe,

The front/back inconsistency is mostly related to the BSDF material primitive. For the 3-phase method you don't have to worry about front/back of the fenestration. (unless you want to use a BSDF backwards, which might be impossible without manually editing the BSDF file).

The BSDF handling has matured quite a bit since the early days of the three-phase method. These days dctimestep can use either front transmission or back transmission applying reciprocity principles for the three phase method.

Andy

On Wed, Jul 2, 2014 at 9:24 AM, CHI-German Molina <[email protected]> wrote:
Guiseppe,

The three-phase method simulation method does not use the geometry of the shading device to work. In fact, one advantage of it is that only the BSDF.xml file is needed. If you check Andy's Three-phase method tutorial, you will see that the calculation of the V and D matrices do not require neither the geometry of the shading device nor the BSDF of it (thus making it very easy to try multiple fenestration systems).

Adding Geometry information to the BSDF file is useful for using pkgBSDF; not really for the 3phase method. When rays have to go through the fenestration system (i.e. rendering a room with venetian blinds, or when calculating the third matrix of the 5 phase method) a combination of two illums that "wrap" the geometry and the geometry itself seems to be more efficient. My understanding (I might be completely wrong) is that the illums are used to transfer the diffuse (indirect??) radiation; and the geometry is used for transfering direct radiation, casting shadows.

My answer to the first question:

1. in the equation i=VTDs the T matrix has to contain the window geometry or take knowledge of these from the other two matrix(V,D)?

Nope. After the V and D matrices are calculated, the simulation is performed by simply multiplying matrices... no geometry.

The second question is something that confuses me... it would be good to have clarification here.

Hope this helps!

Germán

2014-07-02 11:54 GMT-04:00 Giuseppe De Michele <[email protected]>:
Dear all,

I am working with the 3 phase method (only from a few weeks) and I am trying to understand the BSDF file format and how the 3 phase method read it.

I have noticed that if I use the bsdf created with the command:
genBSDF -n 4 +f +b -geom meter material.rad blinds.rad > blinds.xml
the .xml file contain same geometrical dimension (height, width). In fact if I use the command:
pkgBSDF -s blinds.xml > blinds_pkg.rad
the output file contain the original geometry.

Instead if I use the BSDF created or contained in the database of WINDOW 7 these file do not contain a geometry.
With pkgBSDF I got an error.

My questions are:
1. in the equation i=VTDs the T matrix has to contain the window geometry or take knowledge of these from the other two matrix(V,D)?
2. I have understood that 3 phase method uses only the front transmission data [A. McNeil, Three-Phase Method tutorial] but in
an other discussion [ http://www.radiance-online.org/pipermail/radiance-general/2012-October/008969.html ] I have discovered that WINDOW and genBSDF use an opposite meaning of front and back, so the front transmission regards radiance or window meaning?And what part of the T matrix I have to use in the 3 phase method for the respective cases (WINDOW or genBSDF)?

Kind regards,
Giuseppe

_______________________________________________
Radiance-general mailing list
[email protected]
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
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
Giuseppe De Michele

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
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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8

Awesome.

Thanks Greg!

···

2014-07-07 11:39 GMT-04:00 Greg Ward <[email protected]>:

Reciprocity works for every BSDF type in Radiance except isotropic tensor
trees, so specify +f with the -t3 option if you want transmission to go
both ways. Also, you need +f to get the reflected rays on the opposite
side of the surface, so you may want it under some other circumstances as
well.

The geometry (if present) is used for shadow calculation during the direct
calculation and for viewing the system, while the BSDF is used for all
other purposes.

Cheers,
-Greg

*From: *CHI-German Molina <[email protected]>

*Subject: *Re: [Radiance-general] BSDF question

*Date: *July 7, 2014 7:39:33 AM PDT

Andy,

How about using BSDFs for ray-tracing calculations? Does it use
reciprocity as well? or should we calculate +b ?

Also, was I correct when I said that the BSDFd "Proxy Geometry" is only
used for ambient calculations, and the geometry for Direct?

THANKS!

German

2014-07-07 10:32 GMT-04:00 Andrew McNeil <[email protected]>:

Hi Giuseppe,

You only really need either +f or +b, not both. genBSDF does +b by
default so if you only wanted to do the forward direction you should use +f
-b. Doing one direction takes about half as much time as doing both
directions. However, if you want to import into Window you'll need to do
both directions.

Andy

On Thu, Jul 3, 2014 at 12:45 AM, Giuseppe De Michele <[email protected]> >> wrote:

Germán and Andy,

meanwhile thank you for the answers and sorry if my questions are a
little bit confused. I am a newbie of the "lighting art" and I am studying
this concepts almost alone.
So if I understood, when I create a BSDF matrix with genBSDF I add the
+f +b options in order to obtain both transmission matrix and then
dctimestep does the rest, doesn't it?

Thanks for yours great help,
Giuseppe

2014-07-02 19:12 GMT+02:00 Andrew McNeil <[email protected]>:

Giuseppe,

The front/back inconsistency is mostly related to the BSDF material
primitive. For the 3-phase method you don't have to worry about front/back
of the fenestration. (unless you want to use a BSDF backwards, which might
be impossible without manually editing the BSDF file).

The BSDF handling has matured quite a bit since the early days of the
three-phase method. These days dctimestep can use either front transmission
or back transmission applying reciprocity principles for the three phase
method.

Andy

On Wed, Jul 2, 2014 at 9:24 AM, CHI-German Molina <[email protected]> >>>> wrote:

Guiseppe,

The three-phase method simulation method does not use the geometry of
the shading device to work. In fact, one advantage of it is that only the
BSDF.xml file is needed. If you check Andy's Three-phase method tutorial,
you will see that the calculation of the V and D matrices do not require
neither the geometry of the shading device nor the BSDF of it (thus making
it very easy to try multiple fenestration systems).

Adding Geometry information to the BSDF file is useful for using
pkgBSDF; not really for the 3phase method. When rays have to go through the
fenestration system (i.e. rendering a room with venetian blinds, or when
calculating the third matrix of the 5 phase method) a combination of two
illums that "wrap" the geometry and the geometry itself seems to be more
efficient. My understanding (I might be completely wrong) is that the
illums are used to transfer the diffuse (indirect??) radiation; and the
geometry is used for transfering direct radiation, casting shadows.

My answer to the first question:

*1. in the equation i=VTDs the T matrix has to contain the window
geometry or take knowledge of these from the other two matrix(V,D)? *

Nope. After the V and D matrices are calculated, the simulation is
performed by simply multiplying matrices... no geometry.

The second question is something that confuses me... it would be good
to have clarification here.

Hope this helps!

Germán

2014-07-02 11:54 GMT-04:00 Giuseppe De Michele <[email protected]>:

Dear all,

I am working with the 3 phase method (only from a few weeks) and I am
trying to understand the BSDF file format and how the 3 phase method read
it.

I have noticed that if I use the bsdf created with the command:
genBSDF -n 4 +f +b -geom meter material.rad blinds.rad > blinds.xml
the .xml file contain same geometrical dimension (height, width). In
fact if I use the command:
pkgBSDF -s blinds.xml > blinds_pkg.rad
the output file contain the original geometry.

Instead if I use the BSDF created or contained in the database of
WINDOW 7 these file do not contain a geometry.
With pkgBSDF I got an error.

My questions are:
1. in the equation i=VTDs the T matrix has to contain the window
geometry or take knowledge of these from the other two matrix(V,D)?
2. I have understood that 3 phase method uses only the front
transmission data [A. McNeil, Three-Phase Method tutorial] but in
an other discussion [
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008969.html
] I have discovered that WINDOW and genBSDF use an opposite meaning of
front and back, so the front transmission regards radiance or window
meaning?And what part of the T matrix I have to use in the 3 phase method
for the respective cases (WINDOW or genBSDF)?

Kind regards,
*Giuseppe*

_______________________________________________
Radiance-general mailing list
[email protected]
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
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
*Giuseppe De Michele*

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
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
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
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.

9

Andy,

now is all clear. Thanks.

Giuseppe

···

2014-07-07 17:42 GMT+02:00 CHI-German Molina <[email protected]>:

Awesome.

Thanks Greg!

2014-07-07 11:39 GMT-04:00 Greg Ward <[email protected]>:

Reciprocity works for every BSDF type in Radiance except isotropic tensor

trees, so specify +f with the -t3 option if you want transmission to go
both ways. Also, you need +f to get the reflected rays on the opposite
side of the surface, so you may want it under some other circumstances as
well.

The geometry (if present) is used for shadow calculation during the
direct calculation and for viewing the system, while the BSDF is used for
all other purposes.

Cheers,
-Greg

*From: *CHI-German Molina <[email protected]>

*Subject: *Re: [Radiance-general] BSDF question

*Date: *July 7, 2014 7:39:33 AM PDT

Andy,

How about using BSDFs for ray-tracing calculations? Does it use
reciprocity as well? or should we calculate +b ?

Also, was I correct when I said that the BSDFd "Proxy Geometry" is only
used for ambient calculations, and the geometry for Direct?

THANKS!

German

2014-07-07 10:32 GMT-04:00 Andrew McNeil <[email protected]>:

Hi Giuseppe,

You only really need either +f or +b, not both. genBSDF does +b by
default so if you only wanted to do the forward direction you should use +f
-b. Doing one direction takes about half as much time as doing both
directions. However, if you want to import into Window you'll need to do
both directions.

Andy

On Thu, Jul 3, 2014 at 12:45 AM, Giuseppe De Michele <[email protected] >>> > wrote:

Germán and Andy,

meanwhile thank you for the answers and sorry if my questions are a
little bit confused. I am a newbie of the "lighting art" and I am studying
this concepts almost alone.
So if I understood, when I create a BSDF matrix with genBSDF I add the
+f +b options in order to obtain both transmission matrix and then
dctimestep does the rest, doesn't it?

Thanks for yours great help,
Giuseppe

2014-07-02 19:12 GMT+02:00 Andrew McNeil <[email protected]>:

Giuseppe,

The front/back inconsistency is mostly related to the BSDF material
primitive. For the 3-phase method you don't have to worry about front/back
of the fenestration. (unless you want to use a BSDF backwards, which might
be impossible without manually editing the BSDF file).

The BSDF handling has matured quite a bit since the early days of the
three-phase method. These days dctimestep can use either front transmission
or back transmission applying reciprocity principles for the three phase
method.

Andy

On Wed, Jul 2, 2014 at 9:24 AM, CHI-German Molina <[email protected]> >>>>> wrote:

Guiseppe,

The three-phase method simulation method does not use the geometry of
the shading device to work. In fact, one advantage of it is that only the
BSDF.xml file is needed. If you check Andy's Three-phase method tutorial,
you will see that the calculation of the V and D matrices do not require
neither the geometry of the shading device nor the BSDF of it (thus making
it very easy to try multiple fenestration systems).

Adding Geometry information to the BSDF file is useful for using
pkgBSDF; not really for the 3phase method. When rays have to go through the
fenestration system (i.e. rendering a room with venetian blinds, or when
calculating the third matrix of the 5 phase method) a combination of two
illums that "wrap" the geometry and the geometry itself seems to be more
efficient. My understanding (I might be completely wrong) is that the
illums are used to transfer the diffuse (indirect??) radiation; and the
geometry is used for transfering direct radiation, casting shadows.

My answer to the first question:

*1. in the equation i=VTDs the T matrix has to contain the window
geometry or take knowledge of these from the other two matrix(V,D)? *

Nope. After the V and D matrices are calculated, the simulation is
performed by simply multiplying matrices... no geometry.

The second question is something that confuses me... it would be good
to have clarification here.

Hope this helps!

Germán

2014-07-02 11:54 GMT-04:00 Giuseppe De Michele <[email protected]>:

Dear all,

I am working with the 3 phase method (only from a few weeks) and I
am trying to understand the BSDF file format and how the 3 phase method
read it.

I have noticed that if I use the bsdf created with the command:
genBSDF -n 4 +f +b -geom meter material.rad blinds.rad > blinds.xml
the .xml file contain same geometrical dimension (height, width). In
fact if I use the command:
pkgBSDF -s blinds.xml > blinds_pkg.rad
the output file contain the original geometry.

Instead if I use the BSDF created or contained in the database of
WINDOW 7 these file do not contain a geometry.
With pkgBSDF I got an error.

My questions are:
1. in the equation i=VTDs the T matrix has to contain the window
geometry or take knowledge of these from the other two matrix(V,D)?
2. I have understood that 3 phase method uses only the front
transmission data [A. McNeil, Three-Phase Method tutorial] but in
an other discussion [
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008969.html
] I have discovered that WINDOW and genBSDF use an opposite meaning of
front and back, so the front transmission regards radiance or window
meaning?And what part of the T matrix I have to use in the 3 phase method
for the respective cases (WINDOW or genBSDF)?

Kind regards,
*Giuseppe*

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