[Radiance-general] RE: Prismatic glazing simulation in PMAP using
Siteco data
Anthony J. Farrell
anthony.farrell at dit.ie
Mon Jun 14 19:53:07 CEST 2004
Thanks Roland, Martin for input,
I meant to make to reference to the Prism1 and Prism2 commands in the 3.5
release of Radiance. I am uncertain of the function file command line
mod prism1 id
5+ coef dx dy dz funcfile transform
0
n A1 A2...An where the new direction variables
So if I wanted to redirect light from a vertical glazed window down at an
angle of 45 degrees onto the working plane what values would I substitute in
for A1 etc?
* DxA DyA DzA and are the normalised direction to the target light source
* dx, dy, dz are?
I sketch of the dimensions would be very helpful, as I just can't picture
the above scenario.
Roland, Is it possible to use Prism1 or Prism2 commands in the PMAP version
of Radiance to forward raytrace from the photon port (the target light
(*luminance* source?)to the target illuminance source (the working plane)?
Martin, could is it possible to model a standard prismatic panel that
redirects vertical light from a light pipe for example, out at an angle of
45degrees onto the working plane? I will be testing one of the siteco panels
on my test rig so would be interesting to compare the results.
Regards,
Anthony.
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Today's Topics:
1. rholo & .hif files (O Graf)
2. Re: Fwd: errors from hdrgen (Martin Matusiak)
3. Fwd: Re: [Radiance-general] Fwd: errors from hdrgen
(Martin Matusiak)
4. Prismatic glazing in radiance PMAP (Anthony J. Farrell)
5. Re: Fwd: errors from hdrgen (Greg Ward)
6. Re: Fwd: errors from hdrgen (Greg Ward)
7. Re: Prismatic glazing in radiance PMAP (Roland Schregle)
8. RE: Prismatic glazing in radiance PMAP (Martin Moeck)
----------------------------------------------------------------------
Message: 1
Date: Fri, 11 Jun 2004 12:21:53 +0100
From: O Graf <s0343631 at sms.ed.ac.uk>
Subject: [Radiance-general] rholo & .hif files
To: radiance-general at radiance-online.org
Message-ID: <1086952913.40c995d153a11 at sms.ed.ac.uk>
Content-Type: text/plain; charset=ISO-8859-15
Hi!
What is actually the trick for setting the right values for the 'section'
variable in a .hif file? The rad-file which I use contains a laser scan of a
real room and I have no idea what are the right values for the 'section'
variable. Every time I change the values the actual grid appears somewhere
in
the middle of the whole scenery and I get such warnings as
dev/ogl.hdi: no sections visible from this view
if I try to turn around or to zoom. I understand why these warnings come,
but I
would like to know how I can estimate the values for the section to avoid
the
warnings and to be able to see the whole room and not only 2 walls.
Another funny thing is that the whole room stands on its side, i.e. lines
that
are supposed to be vertical appear horizontal. First I thought the view
direction might be wrong, but if I run the same .oct-file with rview using
the
same view-file everything is perfect. In addition to the right view
direction
the rview-command produces colored images and rholo gives only grey values
from
the same .oct-file. Is there a particular reason for such different results?
regards,
Olga
------------------------------
Message: 2
Date: Fri, 11 Jun 2004 14:17:29 +0200
From: Martin Matusiak <alex at juventuz.net>
Subject: Re: [Radiance-general] Fwd: errors from hdrgen
To: Radiance general discussion <radiance-general at radiance-online.org>
Message-ID: <200406111417.29402.alex at juventuz.net>
Content-Type: text/plain; charset="iso-8859-1"
> I hdr'ed all ouf the 13 images in one go, and apart for some 'poor
> convergence' (orders 1, 3, 4 and 5) warnings, it worked fine. There is
> no apparent distortion.
I repeated the process using the manual mode of the camera rather than
aperture priority. Again 13 images (same room, scene was a bit different as
I
eliminated the sky in the framing) and I was able to compute a hdr. But the
alignment problem still persists, I use the -a switch to turn it off.
Later I took a couple more images and used the calibration data to compute a
hdr and read the luminance values off it. It turns out that those are
somewhat accurate so that's a good sign!
However, I'm still not quite satisfied. Obviously, the calibration procedure
is meant to give a most accurate static description of the camera, but I
used
the camera's automatic whitebalance correction, so that's a variable. My
question is a complete novice one: how does the whitebalance affect the
luminance? What can I do to eliminate this variable (if it is significant).
Martin
------------------------------
Message: 3
Date: Fri, 11 Jun 2004 14:21:55 +0200
From: Martin Matusiak <alex at juventuz.net>
Subject: Fwd: Re: [Radiance-general] Fwd: errors from hdrgen
To: radiance-general at radiance-online.org
Message-ID: <200406111421.55929.alex at juventuz.net>
Content-Type: text/plain; charset="iso-8859-1"
I forgot to mention that my "cvs build" of hdrgen is from last week, so
there
could have been changes from the version you have.
Martin
---------- Forwarded Message ----------
Subject: Re: [Radiance-general] Fwd: errors from hdrgen
Date: Friday 11 June 2004 14:17
From: Martin Matusiak <alex at juventuz.net>
To: Radiance general discussion <radiance-general at radiance-online.org>
> I hdr'ed all ouf the 13 images in one go, and apart for some 'poor
> convergence' (orders 1, 3, 4 and 5) warnings, it worked fine. There is
> no apparent distortion.
I repeated the process using the manual mode of the camera rather than
aperture priority. Again 13 images (same room, scene was a bit different as
I
eliminated the sky in the framing) and I was able to compute a hdr. But the
alignment problem still persists, I use the -a switch to turn it off.
Later I took a couple more images and used the calibration data to compute a
hdr and read the luminance values off it. It turns out that those are
somewhat accurate so that's a good sign!
However, I'm still not quite satisfied. Obviously, the calibration procedure
is meant to give a most accurate static description of the camera, but I
used
the camera's automatic whitebalance correction, so that's a variable. My
question is a complete novice one: how does the whitebalance affect the
luminance? What can I do to eliminate this variable (if it is significant).
Martin
-------------------------------------------------------
------------------------------
Message: 4
Date: Fri, 11 Jun 2004 14:51:26 +0100
From: "Anthony J. Farrell" <anthony.farrell at dit.ie>
Subject: [Radiance-general] Prismatic glazing in radiance PMAP
To: radiance-general at radiance-online.org
Message-ID: <OJEGILOIGGNAEAODNHIICEEGCDAA.anthony.farrell at dit.ie>
Content-Type: text/plain; charset=iso-8859-1
Hi,
I am trying to model a simple sheet of prismatic glazing, but am unclear of
the dimension variable set out in the PMAP user manual for the prism
command.
Could anyone please forward me a drawing or sketch of what this command is
based?
Kind regards,
Anthony
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------------------------------
Message: 5
Date: Fri, 11 Jun 2004 08:09:17 -0700
From: Greg Ward <gward at lmi.net>
Subject: Re: [Radiance-general] Fwd: errors from hdrgen
To: Radiance general discussion <radiance-general at radiance-online.org>
Message-ID: <4EE8BCAC-BBB9-11D8-BDAA-000A95BB392A at lmi.net>
Content-Type: text/plain; charset=US-ASCII; format=flowed
Hi Martin,
I believe that hdrgen isn't coming up with a good response function for
your camera with this scene, probably due to the strong color cast of
the walls. Since hdrgen (and Photosphere) compute the responses for
each of the RGB channels, using a lot of colorful patch samples can
skew the result. I've never seen such an extreme example before,
though -- most walls are off-white so this hadn't come up. Come to
think of it, the tendency of cameras to super-saturate their colors
could spell trouble in such cases, and I probably should modify my
algorithm to avoid colorful patch samples.
Thanks for the image set -- I'll run some experiments on my end to see
if I can improve on this. It is important to fix the white balance
whenever you take an HDR sequence, as the camera in auto white mode
will alter the coefficients between exposures otherwise, making it
impossible to get a consistent result.
-Greg
> From: Martin Matusiak <alex at juventuz.net>
> Date: June 11, 2004 5:17:29 AM PDT
>
>> I hdr'ed all ouf the 13 images in one go, and apart for some 'poor
>> convergence' (orders 1, 3, 4 and 5) warnings, it worked fine. There is
>> no apparent distortion.
>
> I repeated the process using the manual mode of the camera rather than
> aperture priority. Again 13 images (same room, scene was a bit
> different as I
> eliminated the sky in the framing) and I was able to compute a hdr.
> But the
> alignment problem still persists, I use the -a switch to turn it off.
>
> Later I took a couple more images and used the calibration data to
> compute a
> hdr and read the luminance values off it. It turns out that those are
> somewhat accurate so that's a good sign!
>
> However, I'm still not quite satisfied. Obviously, the calibration
> procedure
> is meant to give a most accurate static description of the camera, but
> I used
> the camera's automatic whitebalance correction, so that's a variable.
> My
> question is a complete novice one: how does the whitebalance affect the
> luminance? What can I do to eliminate this variable (if it is
> significant).
>
> Martin
------------------------------
Message: 6
Date: Fri, 11 Jun 2004 09:18:46 -0700
From: Greg Ward <gward at lmi.net>
Subject: [Radiance-general] Re: Fwd: errors from hdrgen
To: Radiance general discussion <radiance-general at radiance-online.org>
Message-ID: <03936172-BBC3-11D8-992A-000A95BB392A at lmi.net>
Content-Type: text/plain; charset=US-ASCII; format=flowed
Hi again.
Well, I played around with limiting the saturation on patches, and it
only seems to make matters worse; I'm not sure why. I think it's
because you don't have enough unsaturated pixels in your scene for it
to work, but I'll have to perform some more experiments to determine
that for certain. For now, you'll just have to find a more "neutral"
scene to perform your calibration on, then save the response function
and reuse it for other scenes, which is what I've been doing.
-Greg
> From: Martin Matusiak <alex at juventuz.net>
> Date: June 11, 2004 5:21:55 AM PDT
>
> I forgot to mention that my "cvs build" of hdrgen is from last week,
> so there
> could have been changes from the version you have.
>
> Martin
------------------------------
Message: 7
Date: Fri, 11 Jun 2004 21:11:56 +0200
From: Roland Schregle <ganjatron at gmx.net>
Subject: Re: [Radiance-general] Prismatic glazing in radiance PMAP
To: Radiance general discussion <radiance-general at radiance-online.org>
Message-ID: <40CA03FC.6010504 at gmx.net>
Content-Type: text/plain; charset=us-ascii; format=flowed
Anthony J. Farrell wrote:
> Hi,
>
> I am trying to model a simple sheet of prismatic glazing, but am unclear
of
> the dimension variable set out in the PMAP user manual for the prism
> command.
Dimension variable? If you're referring to the -ds parameter, that
affects the resolution with which the light source surfaces are sampled
during photon emission. Are you referring to the prism material or the
genprism command?
--
Roland Schregle
PhD candidate, Fraunhofer Institute for Solar Energy Systems
RADIANCE Photon Map page: www.ise.fhg.de/radiance/photon-map
END OF LINE. (MCP)
------------------------------
Message: 8
Date: Fri, 11 Jun 2004 16:03:42 -0400
From: "Martin Moeck" <MMoeck at engr.psu.edu>
Subject: RE: [Radiance-general] Prismatic glazing in radiance PMAP
To: "Radiance general discussion"
<radiance-general at radiance-online.org>
Message-ID:
<84F05BA9118BBD4A8FC6409808CE266C113A1F at ENGRMAIL2.engr.psu.edu>
Content-Type: text/plain; charset="utf-8"
Are there any validations of pmap? If desired, I can make measured data
available for some prismatic glazings as shown at www.siteco.de. See
http://www.siteco.de/products/tageslichtsysteme/?currency=EUR&lang=en&javasc
ript=true Click on "large panel prism systems".
Martin, Penn State
-----Original Message-----
From: Roland Schregle [mailto:ganjatron at gmx.net]
Sent: Fri 6/11/2004 3:11 PM
To: Radiance general discussion
Cc:
Subject: Re: [Radiance-general] Prismatic glazing in radiance PMAP
Anthony J. Farrell wrote:
> Hi,
>
> I am trying to model a simple sheet of prismatic glazing, but am unclear
of
> the dimension variable set out in the PMAP user manual for the prism
> command.
Dimension variable? If you're referring to the -ds parameter, that
affects the resolution with which the light source surfaces are sampled
during photon emission. Are you referring to the prism material or the
genprism command?
--
Roland Schregle
PhD candidate, Fraunhofer Institute for Solar Energy Systems
RADIANCE Photon Map page: www.ise.fhg.de/radiance/photon-map
END OF LINE. (MCP)
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