[Radiance-general] Three-Phase Method - subdivision of window with sensor located close to the window

Sat May 7 11:04:14 PDT 2011

Hi David, Greg and Andy,
Have been in Lausanne for a great Daylight Symposium, so it's first now I
find the time to look at your comments.

My bummer! You're right, the -I does not belong. Thanks for noticing the
mistake and explain the reason why :-) :-). This is no excuse, but I did
find it myself when comparing rsensor 'cosine distribution' (from SPOT
distribution) to a simulation with a standard sensor point, and have been
wondering why??

And yep - Andy, I'll run it all again. Both three phase method and standard
Radiance technique. I'll let you know how it works out.

THANKS :-)
Best,
Anne

On Mon, May 2, 2011 at 9:00 PM, <
radiance-general-request at radiance-online.org> wrote:

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> Today's Topics:
>
>   1. Re: Three-Phase Method - subdivision of window with sensor
>      located close to the window (David Geisler-Moroder)
>   2. Re: Three-Phase Method - subdivision of window    with sensor
>      located close to the window (Greg Ward)
>   3. Re: Three-Phase Method - subdivision of window    with sensor
>      located close to the window (Andy McNeil)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 2 May 2011 11:41:44 +0200
> From: David Geisler-Moroder <david.moroder at gmail.com>
> To: Radiance general discussion <radiance-general at radiance-online.org>
> Subject: Re: [Radiance-general] Three-Phase Method - subdivision of
>        window with sensor located close to the window
> Message-ID: <BANLkTi=tG6Ndz-tKXk=_e49raaxwLaeJAA at mail.gmail.com>
> Content-Type: text/plain; charset="windows-1252"
>
> Hi Anne,
>
> another thing that came to my mind...
>
> You are calling rtcontrib for the VMX using rsensor in your script like
> that:
>    rsensor -h -rd 1000 -vf views/luxstat.vf sensors/WattStopper_LS-290C.dat
> . |\
>       rtcontrib -c 1000 -f klems_int.cal -bn Nkbins -fo -o
> results/"$vmxname"_%s.vmx \
>       -b kbinS -m windowlight -b kbinS -m windowlightsens \
>       -I+ -ab 3 -ad 2000 -ds .15 -lw 1e-4 model_vmx.oct
>
> Do you want to obtain the sensor signal split up into the Klems bins?
> If yes, I'm not sure if it works like that...
>
> You are using rsensor to generate 1000 rays (i.e. origin and direction)
> according to the sensor-file.
> These points and directions are then given to rtcontrib, where you use -c
> 1000 to accumulate all
> 1000 results and -I+ to switch to irradiances.
> However, this means that rtcontrib calculates irradiances for 1000 pairs of
> points and directions as
> if it was e.g. a grid for illuminance calculations. So you do not obtain
> the
> sensor signal, but a mean
> of the 1000 calculated irradiances.
>
> I hope I'm not missing anything...
>
> Cheers,
> David
>
>
>
> 2011/4/30 Anne Iversen <iversen.anne at gmail.com>
>
> > Hi,
> > Maybe I was a bit fast concluding that I'll use glow. Comparing the glow
> > material to the light material reveals a lower sensor signal when the
> direct
> > irradiation is low and the opposite when direct irradiation is high. Do
> you
> > know why I get this? Due to the ?subsampling? problem of window lights as
> > David mentioned because of my sensor location very close to the window??
> And
> > therefore I should stick to glow?
> >
> > I have included the results from the glow simulations in the document:
> > http://dl.dropbox.com/u/9713279/ThreePhaseMethod_Subdivision.pdf
> > (the non-readable legends and axes must be a mac thing...the same happens
> > when I open the documet on my mac, I can read the graphs nicely in the
> pdf
> > on my pc. ...have included some text in the captions, if you want to know
> > what you are looking at ;-))
> >
> > And to your question about my sensor, Andy. The sensor is located on the
> > window head, just behind the glass. The major detection area is to the
> > outside through the window. The sensor used right now comes along with
> the
> > SPOT distribution, and is the WattStopper LD290C - the spatial
> distribution
> > can be seen from the image linked to below. I wouldn't call it a
> > narrow/peaky/tight sensitivity distribution:
> > http://dl.dropbox.com/u/9713279/SensorSpatialResponse.png
> > and I have placed the .dat file here:
> > http://dl.dropbox.com/u/9713279/WattStopper_LS-290C.dat
> > Why do you believe that using glow probably won't make much difference -
> > unless my sensor has a tight and/or peaky sensitivity distribution?
> >
> >
> > Enjoy the weekend. It is pre-summer in Denmark; we've had blue sky for
> the
> > last 14 days, 20C and sun ....who said I miss California?? ;-)
> >
> > Best,
> > Anne
> >
> >
> > ----------------------------------------------------------------------
> >>
> >> Message: 1
> >> Date: Fri, 29 Apr 2011 09:30:48 -0700
> >> From: Andy McNeil <amcneil at lbl.gov>
> >>
> >> To: Radiance general discussion <radiance-general at radiance-online.org>
> >> Subject: Re: [Radiance-general] Three-Phase Method - subdivision of
> >>        window  with sensor located close to the window
> >> Message-ID: <1DB1235F-E7F9-4392-90E3-444D2661F794 at lbl.gov>
> >>
> >> Content-Type: text/plain; charset="us-ascii"
> >>
> >> Hi Anne,
> >> Just curious, how do the glow results compare to the light sources?
>  Could
> >> you update the graph with the sensor signals using the glow material?
> >> Andy
> >>
> >>
> >>
> >>
> >
> > _______________________________________________
> > Radiance-general mailing list
> > Radiance-general at radiance-online.org
> > http://www.radiance-online.org/mailman/listinfo/radiance-general
> >
> >
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> ------------------------------
>
> Message: 2
> Date: Mon, 2 May 2011 09:14:35 -0700
> From: Greg Ward <gregoryjward at gmail.com>
> To: Radiance general discussion <radiance-general at radiance-online.org>
> Subject: Re: [Radiance-general] Three-Phase Method - subdivision of
>        window  with sensor located close to the window
> Message-ID: <CDF2C1A4-D5B1-42E2-AAF6-604AB5EFAB5D at lmi.net>
> Content-Type: text/plain; charset=us-ascii
>
> Hi Anne,
>
> I believe David is correct.  I should have looked at your command more
> closely.  The -I+ switch does not belong.  If you remove it (or set -I-),
> then the computed radiance values will be accumulated according to the
> distributed rays out of rsensor, then split again into Klems direction bins
> by rtcontrib.  The *.vmx files will each contain a single row of 145 RGB
> coefficients, which processed through dctimestep with the window's BTDF file
> will ultimately yield a single sensor value at each time step.
>
> I hope this makes sense.  I find it a bit confusing, myself!
>
> Best,
> -Greg
>
> > From: David Geisler-Moroder <david.moroder at gmail.com>
> > Date: May 2, 2011 2:41:44 AM PDT
> >
> > Hi Anne,
> >
> > another thing that came to my mind...
> >
> > You are calling rtcontrib for the VMX using rsensor in your script like
> that:
> >     rsensor -h -rd 1000 -vf views/luxstat.vf
> sensors/WattStopper_LS-290C.dat . |\
> >        rtcontrib -c 1000 -f klems_int.cal -bn Nkbins -fo -o
> results/"$vmxname"_%s.vmx \
> >        -b kbinS -m windowlight -b kbinS -m windowlightsens \
> >        -I+ -ab 3 -ad 2000 -ds .15 -lw 1e-4 model_vmx.oct
> >
> > Do you want to obtain the sensor signal split up into the Klems bins?
> > If yes, I'm not sure if it works like that...
> >
> > You are using rsensor to generate 1000 rays (i.e. origin and direction)
> according to the sensor-file.
> > These points and directions are then given to rtcontrib, where you use -c
> 1000 to accumulate all
> > 1000 results and -I+ to switch to irradiances.
> > However, this means that rtcontrib calculates irradiances for 1000 pairs
> of points and directions as
> > if it was e.g. a grid for illuminance calculations. So you do not obtain
> the sensor signal, but a mean
> > of the 1000 calculated irradiances.
> >
> > I hope I'm not missing anything...
> >
> > Cheers,
> > David
>
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 2 May 2011 10:07:55 -0700
> From: Andy McNeil <amcneil at lbl.gov>
> To: Radiance general discussion <radiance-general at radiance-online.org>
> Subject: Re: [Radiance-general] Three-Phase Method - subdivision of
>        window  with sensor located close to the window
> Message-ID: <D7FA3DC1-A078-4A04-9615-AC057B36843E at lbl.gov>
> Content-Type: text/plain; charset=us-ascii
>
>
> On Apr 30, 2011, at 6:11 AM, Anne Iversen wrote:
>
> > Why do you believe that using glow probably won't make much difference -
> unless my sensor has a tight and/or peaky sensitivity distribution?
>
>
> Low resolution sampling of the outgoing window directions will only affect
> calculations on surfaces near the window.  And they should just cause noise
> that is a fraction of the values from the direct sampling of the window by
> rsensor.  So the only way I can think that glow vs. light would make a
> sizable difference is if your sensor is somewhat shielded from the window
> (by sensitivity or by placement) and/or most of the rsensor samples a sent
> to surfaces near the window ( ie focused sensitivity).  Neither of these
> seem to be the cause though using -I+ would have had the effect of masking
> the direct contribution from the window in a similar way because rsensor
> rays that hit the window don't return a direct value but instead start an
> iluminance calculation on the window.
>
> I'd suggest that while you are running everything again without -I that you
> also simulate using classic Radiance techniques (ie not the three-phase
> method).
>
> Andy
>
>
>
>
> ------------------------------
>
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>
> End of Radiance-general Digest, Vol 87, Issue 1
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