60Watt bulb luminaries data

Anthony_J_Farrell · June 30, 2004, 11:42am

I am currently carrying out basic validation techniques of the Radiance
software using a black box and standard 60Watt bulb therein.

I cannot locate a standard incandescent 60W bulb (just bare hung from
ceiling, no lamp shade) on the desktop radiance program.

Can anyone help me by way of an add on file for a standard light bulb (even
if not 60W!) or refer me to a suitable IESNA file?

Kind regards

Anthony

···

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Today's Topics:

   1. Re: Illuminance calculation on a virtual surface? ([email protected])
   2. Re: colorpict and materials (Lars O. Grobe)
   3. Re: colorpict and materials (Jack de Valpine)

----------------------------------------------------------------------

Message: 1
Date: Tue, 29 Jun 2004 04:18:48 -0700
From: [email protected]
Subject: Re: [Radiance-general] Illuminance calculation on a virtual
surface?
To: [email protected], Radiance general discussion
<[email protected]>
Message-ID: <[email protected]>
Content-Type: text/plain; charset=ISO-8859-1

OK, Rob -- you got me. Your little trick would work. I don't think he
really needs it, though, since he already has a method for generating
the grid points for rtrace. He can simply increase the resolution of
the grid he already has (as Raphael suggested) and/or upsample the
result using pfilt. Or your method. All will work.

-Greg

Quoting Rob Guglielmetti <[email protected]>:

Hi Greg, Hi John,

Greg Ward wrote:

> No good. Trans gets ignored by the rpict -i option. Just use pfilt to
> scale the illuminance map if it's not big enough. (John M's suggestion
> -- he's sitting next to me in Leicester.)

Oh yeah? =8-p

vwrays -x XRES -y YRES -vf viewfile -fd | rtrace -h -fd -opn octree \
> rtrace -fdc -I render_options -x XRES -y YRES octree > illum_picture.pic

Greg, does this look familiar? A little ditty from a year or so ago?
You sent me this tip when I asked you how to get illuminance on a
building's curtain wall. The first rtrace computes the intersection
point (which is fast) and the second rtrace does the illuminance
calculation. Cool, yes? Yes.

Now, given this little tip, could he use trans as I described?

------------------------------

Message: 2
Date: Tue, 29 Jun 2004 14:34:03 +0300
From: Lars O. Grobe <[email protected]>
Subject: Re: [Radiance-general] colorpict and materials
To: Radiance general discussion <[email protected]>
Message-ID: <[email protected]>
Content-Type: text/plain; charset=US-ASCII; format=flowed

Hi,

sorry, so again, I try to be clear in asking this time By the way,
have nice holidays (I hope that's the reason for your travel ;-)!

All is about the question how to map pictures onto a surface without
corrupting its material properties. I understand that colorpict
multiplies the material color components with those of the picture.

If I have a grayscale image processed by normpat (which means that the
average gray value is 1.0) and apply it to a material, the overall
color and brightness will remain the same. So I get the "pattern" from
the image, but the surface still has the correct material properties
(color, brightness etc). I used this so far.

Now I want to use a colored picture for mapping. I also apply normpat
to it, so, as far as I understand, the average of all R, G and B must
be 1.0, right? For example, I use a normpat'ed picture of green marble.
I than apply this using colorpict to a surface, which has a "marble"
material. Will the overall color and brightness still be that of the
defined material, as the picture map has the average of 1.0?

The background: I try to use exact data for material definitions, but
the image maps can't all be color corrected. So I want the overall
color and brightness from defined materials, e.g. from the plastic
material, and use the map only for what I would call "local color
variation". The reason is that I have e.g. red marble, got its color,
brightness and all that defined as plastic marble. But the marble has
blue particles which won't appear if I use a grayscale imagemap. So I
want to use a normpat'ed (NOT colorcorrected e.g. by macbethcal!) to
bring these blue parts onto the surface. The whole surface however must
still have the average color of my plastic marble material.

If I understand the man-page of normpat, that's just what it was
invented for. However, I am a bit unsure, as all Radiance documentation
uses colorpict with a bright white material.

TIA+CU, Lars.
--
Lars O. Grobe
[email protected]

------------------------------

Message: 3
Date: Tue, 29 Jun 2004 09:38:59 -0400
From: Jack de Valpine <[email protected]>
Subject: Re: [Radiance-general] colorpict and materials
To: Radiance general discussion <[email protected]>
Message-ID: <[email protected]>
Content-Type: text/plain; charset="us-ascii"

Hi Lars,

I believe that what you need to do is take your colorpict modifier and
apply it to a material such as a plastic that uses the reflectance of
your material sample as the rgb parameters. I believe that you DO want
to use macbethcal to callibrate the color values of the image and
determine an estimated reflectance. Then using normpat on the image will
move the values in image so the average is 1.0.

So steps as follows:

   1. acquire sample material image by photography, scan....
   2. callibrate sample image with macbethcal
   3. use callibrated sample image to estimate average color
   4. calculate reflectance based on average color values, grey(r,g,b)
   5. normpat the callibrated image

Then create material as follows:

void colorpict color.image.pattern
7 red green blue <normpat picture>.pic picture.cal Px Py
0
1 <aspect>

color.image.pattern plastic color.image.material
0
0
5 <grey(r,g,b)> <grey(r,g,b)> <grey(r,g,b)> <s> <r>

Since the colorpict is normalized to an average value of one, it will
modify the plastic around the reflectance of the plastic. For example,
if colorpict returns 1.1 for red then the red of the plastic will be 10%
brighter.

In short I think that there are two main ways to use colorpict

   1. final reflectance set by colorpict image - colorpict is used to
      set final reflectance of material, that is use callibrated image
      colorpict modifier and material with reflectance of 1.0
   2. final reflectance set by base material - colorpict is used to
      modify reflectance set by material, that is normpat image
      colorpict modifier is used to modify reflectance set by material

I hope this is helpful.

Regards,

-Jack

Lars O. Grobe wrote:

Hi,

sorry, so again, I try to be clear in asking this time By the way,
have nice holidays (I hope that's the reason for your travel ;-)!

All is about the question how to map pictures onto a surface without
corrupting its material properties. I understand that colorpict
multiplies the material color components with those of the picture.

If I have a grayscale image processed by normpat (which means that the
average gray value is 1.0) and apply it to a material, the overall
color and brightness will remain the same. So I get the "pattern" from
the image, but the surface still has the correct material properties
(color, brightness etc). I used this so far.

Now I want to use a colored picture for mapping. I also apply normpat
to it, so, as far as I understand, the average of all R, G and B must
be 1.0, right? For example, I use a normpat'ed picture of green
marble. I than apply this using colorpict to a surface, which has a
"marble" material. Will the overall color and brightness still be that
of the defined material, as the picture map has the average of 1.0?

The background: I try to use exact data for material definitions, but
the image maps can't all be color corrected. So I want the overall
color and brightness from defined materials, e.g. from the plastic
material, and use the map only for what I would call "local color
variation". The reason is that I have e.g. red marble, got its color,
brightness and all that defined as plastic marble. But the marble has
blue particles which won't appear if I use a grayscale imagemap. So I
want to use a normpat'ed (NOT colorcorrected e.g. by macbethcal!) to
bring these blue parts onto the surface. The whole surface however
must still have the average color of my plastic marble material.

If I understand the man-page of normpat, that's just what it was
invented for. However, I am a bit unsure, as all Radiance
documentation uses colorpict with a bright white material.

TIA+CU, Lars.
--
Lars O. Grobe
[email protected]

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Radiance-general mailing list
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--
# John E. de Valpine
# president
#
# visarc incorporated
# http://www.visarc.com
#
# channeling technology for superior design and construction

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John_Mardaljevic1 · June 30, 2004, 1:32pm

Anthony,

Wait a moment whilst the spots before my eyes subside. Ah, that's better.

I am currently carrying out basic validation techniques of the Radiance
software using a black box and standard 60Watt bulb therein.

I cannot locate a standard incandescent 60W bulb (just bare hung from
ceiling, no lamp shade) on the desktop radiance program.

Can anyone help me by way of an add on file for a standard light bulb (even
if not 60W!) or refer me to a suitable IESNA file?

The results you get are likely to depend on the size of the box
and the type of lamp, not to mention a few other factors.

You could model the bulb as a luminous sphere. But you'd have to know
what the luminance of the bulb was. Also, a sphere light source is not
subdivided, i.e. it is sampled by a single ray (p511 RwR). Which may
cause problems if the box is small compared to the bulb. A 'frosted'
or pearl bulb may have a largely isotropic luminous output, provided you
don't see too much of the (luminous) shank where it connects to the
socket. Any measured output distribution (say, IENSA) would, I guess,
be sensitive to the type of lamp. And it would assume a 'point source'
distribution, even though you would model it as, say, a disc or polygon.

Squinting at my desk lamp through a pinched-finger aperture (hence the
spots) revealed that the uniform luminance of the pearl bulb was an
illusion - much of the output of the bulb is from around the filament.

In sort, I suspect that any comparison between measurement and predictions
for your bulb & box will say much about the precision of the photometry,
maybe a little bit about the limitations of single ray light source sampling,
and not much at all about the intrinsic accuracy of Radiance for realistic
architectural scenarios (electric or daylighting). The direct light source
calculation for small angular light sources (e.g. 'spherical' bulb from
several feet away with no occlusion) is pretty much a 'no brainer' and
Radiance will give a result that is near as dammit to the exact solution.
When you get close up to a non-ideal bulb however, then it's a matter of
getting the photometry right.

-John

···

-----------------------------------------------
Dr. John Mardaljevic
Senior Research Fellow
Institute of Energy and Sustainable Development
De Montfort University
The Gateway
Leicester
LE1 9BH, UK
+44 (0) 116 257 7972
+44 (0) 116 257 7981 (fax)

[email protected]
http://www.iesd.dmu.ac.uk/~jm

Martin_Moeck1 · June 30, 2004, 4:07pm

Anthony,

You can download an IES photometric file for a PAR 60W incandescent narrow flood from Osram Sylvania at

www.personal.psu.edu/mum13/60PAR30.CAP.NFL25.ies <http://www.personal.psu.edu/mum13/60PAR30.CAP.NFL25.ies>

Use "ies2rad 60PAR30.CAP.NFL25.ies"

This will create the file "60PAR30.CAP.NFL25.rad" in metric units (meters).

I never saw photometric files for simple incandescent lamps.

I am currently running a fairly accurate simulation in AGI32 V1.7, which will complete in 3 hours for a simple empty box 3X3X3 meters and one PAR lamp.

Martin Moeck, Penn State

···

-----Original Message-----
  From: Anthony J. Farrell [mailto:[email protected]]
  Sent: Wed 6/30/2004 7:42 AM
  To: [email protected]
  Cc:
  Subject: [Radiance-general] RE: 60Watt bulb luminaries data

  I am currently carrying out basic validation techniques of the Radiance
  software using a black box and standard 60Watt bulb therein.

  I cannot locate a standard incandescent 60W bulb (just bare hung from
  ceiling, no lamp shade) on the desktop radiance program.

  Can anyone help me by way of an add on file for a standard light bulb (even
  if not 60W!) or refer me to a suitable IESNA file?

  Kind regards

  Anthony

Krzysztof_Wandachowi · July 1, 2004, 2:29pm

You can find prepared files for incandescent lamp with clear bulb. The
only thing you should change is luminous flux in klm, because these
files are prepared for 100W lamp. Change the line "3 1.35 1.35 1.35" in
z100p.rad file for "3 0.71 0.71 0.71".

You can find these files at:
http://lumen.iee.put.poznan.pl/kw/oprawy/z100p.rad
http://lumen.iee.put.poznan.pl/kw/oprawy/z100p.dat

Descriptions are in polish because these materials I've prepared are for
my students.
z100p.rad includes all information about lamp, this lamp is assumed as
small sphere 0.01 radius.
z100p.dat includes information about light distribution of 100W
incandescent lamp.

You have to use Radiance instead of Desktop Radiance to prepare
calculation.

Good luck!

Krzysztof.

···

----- Original Message -----
From: "Anthony J. Farrell" <[email protected]>
To: <[email protected]>
Sent: Wednesday, June 30, 2004 1:42 PM
Subject: [Radiance-general] RE: 60Watt bulb luminaries data

I am currently carrying out basic validation techniques of the Radiance
software using a black box and standard 60Watt bulb therein.

I cannot locate a standard incandescent 60W bulb (just bare hung from
ceiling, no lamp shade) on the desktop radiance program.

Can anyone help me by way of an add on file for a standard light bulb

(even

if not 60W!) or refer me to a suitable IESNA file?

Kind regards

Anthony

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of
[email protected]
Sent: 30 June 2004 10:59
To: [email protected]
Subject: Radiance-general Digest, Vol 4, Issue 25

Send Radiance-general mailing list submissions to
[email protected]

To subscribe or unsubscribe via the World Wide Web, visit
http://www.radiance-online.org/mailman/listinfo/radiance-general
or, via email, send a message with subject or body 'help' to
[email protected]

You can reach the person managing the list at
[email protected]

Martin_Moeck1 · July 1, 2004, 3:46pm

Model comparisons are tricky. All sorts of calibration and measurement error5s occur. Do not use a 0.5 m box because it is too small (near field photometry problems). In addition, black has a reflectance of 5% unless you have a heavy sand texture, which gets it down to 2%.

A comparison between radiosity code and radiance code is at

www.personal.psu.edu/mum13/agi_rad.pdf

The reflectance is 50% diffuse.

Martin, Penn State

P.S. I would have to run point by point values to do a complete error analysis, but either Radiance or AGI32 1.7 draws the PAR beam not right. The Radiance beam looks a little bit too soft.

···

------------------------------------------------------------

Hi Martin,

Thanks for the reference file.

Have you published any comparison or know of any comparison for lamps and
enclosures such as a black box?

I have constructed a simple 0.5 cube with black walls and lamp socket
central to the ceiling. Should I replace my GE lamp with the PAR lamp?

With the par lamp file you sent me, do I simple draw the lamp as per its
actual dimensions, and assign the rad file to it?

Regards, and thanks for the help,

Anthony

  -----Original Message-----
  From: Krzysztof Wandachowicz [mailto:[email protected]]
  Sent: Thu 7/1/2004 10:29 AM
  To: Radiance general discussion
  Cc:
  Subject: Re: [Radiance-general] RE: 60Watt bulb luminaries data

  You can find prepared files for incandescent lamp with clear bulb. The
  only thing you should change is luminous flux in klm, because these
  files are prepared for 100W lamp. Change the line "3 1.35 1.35 1.35" in
  z100p.rad file for "3 0.71 0.71 0.71".

  You can find these files at:
  http://lumen.iee.put.poznan.pl/kw/oprawy/z100p.rad
  http://lumen.iee.put.poznan.pl/kw/oprawy/z100p.dat

  Descriptions are in polish because these materials I've prepared are for
  my students.
  z100p.rad includes all information about lamp, this lamp is assumed as
  small sphere 0.01 radius.
  z100p.dat includes information about light distribution of 100W
  incandescent lamp.

  You have to use Radiance instead of Desktop Radiance to prepare
  calculation.

  Good luck!

  Krzysztof.

  ----- Original Message -----
  From: "Anthony J. Farrell" <[email protected]>
  To: <[email protected]>
  Sent: Wednesday, June 30, 2004 1:42 PM
  Subject: [Radiance-general] RE: 60Watt bulb luminaries data

  > I am currently carrying out basic validation techniques of the Radiance
  > software using a black box and standard 60Watt bulb therein.
  >
  > I cannot locate a standard incandescent 60W bulb (just bare hung from
  > ceiling, no lamp shade) on the desktop radiance program.
  >
  > Can anyone help me by way of an add on file for a standard light bulb
  (even
  > if not 60W!) or refer me to a suitable IESNA file?
  >
  > Kind regards
  >
  > Anthony
  >
  > -----Original Message-----
  > From: [email protected]
  > [mailto:[email protected]]On Behalf Of
  > [email protected]
  > Sent: 30 June 2004 10:59
  > To: [email protected]
  > Subject: Radiance-general Digest, Vol 4, Issue 25
  >
  >
  > Send Radiance-general mailing list submissions to
  > [email protected]
  >
  > To subscribe or unsubscribe via the World Wide Web, visit
  > http://www.radiance-online.org/mailman/listinfo/radiance-general
  > or, via email, send a message with subject or body 'help' to
  > [email protected]
  >
  > You can reach the person managing the list at
  > [email protected]

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

Greg_Ward1 · July 1, 2004, 10:24pm

Hi Martin,

It's difficult to compare these results in false color, because the two programs do not use the same color scale, exactly. You really need to do the point-by-point comparison.

-Greg

···

From: "Martin Moeck" <[email protected]>
Date: July 1, 2004 8:46:55 AM PDT

Model comparisons are tricky. All sorts of calibration and measurement error5s occur. Do not use a 0.5 m box because it is too small (near field photometry problems). In addition, black has a reflectance of 5% unless you have a heavy sand texture, which gets it down to 2%.

A comparison between radiosity code and radiance code is at

www.personal.psu.edu/mum13/agi_rad.pdf

The reflectance is 50% diffuse.

Martin, Penn State

P.S. I would have to run point by point values to do a complete error analysis, but either Radiance or AGI32 1.7 draws the PAR beam not right. The Radiance beam looks a little bit too soft.