[Radiance-general] Ambient parameters optimization/tweaking

[Vaib]

Hello Everyone!

For my master thesis project, I have conducted an experiment to measure
daylighting/lighting illuminance on the last Equinox days in Vienna. The
room is a small hall (7mx9m), has white walls/ceilings, and only North
facing windows. I have measured reflectivity of all the surface to come
closer to the reality.

Now I have to calibrate my simulation model to match its illuminance output
with the measured illuminance, for both daylight and artificial light
condition.

For daylight, gendaylit sky model is used (listed below), and all
artificials lights are off. For this case, I have tried a number of ambient
parameter combinations (listed below), but since all windows are facing
North, the simulation model only results in 0 illuminance. When I rotated
the North offset, to face windows towards South then I get some
illuminance. From this it seems that windows North orientation is the
reason behind 0 illuminance. In measurements, these values are approx. 1500
lux.

My question is: What ambient parameters should be tweaked so that the model
behaves reasonably (especially for daylight)?

I am following Dr.John Mardaljevic's PhD for ambient parameters
combination. But I don't have much time to do an extensive parametric
analysis of these parameters.

Global, and Diffuse irradiance (for gendaylit) are taken from weather
station in place.

I have tried only rtrace. May be I shall use rsensor now ??

Thank you for your time.

Best regards,
Vaib

*Ambient parameter combinations:*
1. rtrace -w -as 512 -ar 512 -aa 0.15 -ab 2 -I -h foo.oct | rcalc -e
'$1=($1*.265+$2*.67+$3*.065)*179'

2. cat allSens.txt | rtrace -w -ab 7 -ad 2048 -as 32 -I -h foo.oct | rcalc
-e '$1=($1*.265+$2*.67+$3*.065)*179'

3. cat allSens.txt | rtrace -w -ab 7 -ad 2048 -ar 2 -aa 0.10 -as 32 -I -h
foo.oct | rcalc -e '$1=($1*.265+$2*.67+$3*.065)*179'

4. cat allSens.txt | rtrace -w -ab 7 -ad 2048 -ar 64 -aa 0.15 -as 512 -I -h
foo.oct | rcalc -e '$1=($1*.265+$2*.67+$3*.065)*179'

*Gendaylit model for (12:00 time):*
# xform -rz 30
# gendaylit 03 22 12:00 -a 48.198724 -o -16.369458 -m -15.00 -W 967.3 187.2
# Ground ambient level: 33.9

void light solar
0
0
3            7791000            7791000            7791000

solar source sun
0
0
4     0.378842567554    -0.642038575073           0.666532
 0.533

void brightfunc skyfunc
6 skybright perezlum.cal -i 1 -rz 30
0
10              38.97              29.25          -0.878528
 -0.366494          12.997644           -3.44062           0.249106
  0.007068
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