[Radiance-general] 2.5-phase method and gendaymtx

[Axel Jacobs]

(Couldn't come up with a sillier subject line for this)

Dear list,

I am trying to use rcontrib and dctimestep in my only-just-invented
2.5-phase method.  The idea is simple: Instead of relying on the patch
brightness to represent both sun and sky, I would like to only use the
patches for the sky, and rely on 'real' suns for an annual simulation.
 This is somewhat related to Andy's 5-phase method, but but I'm still
at the stage where I have simple windows and no BSDF or Klems stuff.
What I am hoping to find out is whether the inclusion of 'proper' suns
makes a difference compared to the old skool rcontrib approach where
the sky patches represent the sun + sky.

I've tarred up the script and all the input files.  They are available here:
http://www.jaloxa.eu/pickup/cbdm4_diffdir.tgz

The script is a bit lengthy:

---------------------8<-----------------------
#!/bin/bash

PROJECT="dds4"
OPT="ab7rtc"
SKYOCT="octrees/${PROJECT}_sky.oct"
SUNOCT="octrees/${PROJECT}_sun.oct"
REINHART=1
WEA="weather/gatwick.wea"
NPROC=5

# Sensor results with header
stmp="tmp"
if [ ! -d $stmp ]; then
    mkdir $stmp
else
    rm -f $stmp/*
fi

wbase=$(basename $WEA .wea)
fsmx="$stmp/${wbase}_m$REINHART.fsmx"     # annual diffuse sky matrix
dsmx="$stmp/${wbase}_m$REINHART.dsmx"     # annual direct sun matrix
csmx="$stmp/${wbase}_m$REINHART.csmx"     # annual combined matrix
suns="$stmp/suns_m${REINHART}.rad"        # annual suns

# Build the diffuse sky matrix for Tregenza subdivision
# -O1 (total solar irradiance), so we can compare against WEA file
echo "  Building annual diffuse sky matrix $fsmx..."
gendaymtx -s -m $REINHART -c 1 1 1 -O1 $WEA > $fsmx

# Build the direct suns
echo "  Building annual suns $suns..."
echo "void light solar 0 0 3 1e6 1e6 1e6" > $suns
npatch=$( echo 1 |rcalc -e MF:2 -f reinhart.cal -e '$1=Nrbins' )
cnt $npatch |rcalc -e MF:$REINHART -f reinsrc.cal -e Rbin=recno \
        -o 'solar source sun 0 0 4 ${ Dx } ${ Dy } ${ Dz } 0.533' >> $suns
gendaymtx -5 -d -m $REINHART -c 1 1 1 -O1 $WEA > $dsmx

# Build direct+diffuse (old skool)
echo "  Building annual combined sun+sky matrix $csmx..."
gendaymtx -m $REINHART -c 1 1 1 -O1 $WEA > $csmx

echo "    Compiling octrees..."
oconv skies/sky_white.rad > $SKYOCT
oconv $suns > $SUNOCT

echo "Grid: roof.pts"
grid=roof.pts
base=$(basename roof .pts)

skdc="$stmp/${PROJECT}_${OPT}_$base.skdc"     # diffuse sky DC
sndc="$stmp/${PROJECT}_${OPT}_$base.sndc"     # direct sun DC

# Run the DDS calculations: Daylight Matrix with header
echo "  Calculating sky DC $skdc..."
cat $grid \
        |rcontrib -n $NPROC @$OPT.opt \
        -e MF:$REINHART -f reinhart.cal -bn Nrbins -b rbin \
        -o $skdc -m sky_glow $SKYOCT

echo "  Calculating sun DC $sndc..."
cat $grid \
        |rcontrib -n $NPROC @$OPT.opt \
        -e MF:$REINHART -f reinhart.cal -bn Nrbins -b rbin \
        -o $sndc -m solar $SUNOCT


fimx="$stmp/${PROJECT}_${OPT}_$base.fimx"     # annual diffuse irradiance matrix
dimx="$stmp/${PROJECT}_${OPT}_$base.dimx"     # annual direct irradiance matrix
cimx="$stmp/${PROJECT}_${OPT}_$base.cimx"     # annual combined
irradiance matrix

# Produce annual (grey) sensor irradiance matrix
echo "  Calculating annual direct irradiance $dimx..."
dctimestep -n 8760 $sndc $dsmx |tr '\t' '\n' |sed -e '/^\s*$/d' \
        |rcalc -e '$1=$1' > $dimx

echo "  Calculating annual diffuse irradiance $fimx..."
dctimestep -n 8760 $skdc $fsmx |tr '\t' '\n' |sed -e '/^\s*$/d' \
        |rcalc -e '$1=$1' > $fimx

echo "  Calculating annual combined irradiance $cimx..."
dctimestep -n 8760 $skdc $csmx |tr '\t' '\n' |sed -e '/^\s*$/d' \
        |rcalc -e '$1=$1' > $cimx

imx2="$stmp/${PROJECT}_${OPT}_$base.imx2"   # annual sky+sun irradiance matrix
irr="$stmp/${PROJECT}_${OPT}_$base.irr"    # annual grey irradiance

# Add direct and diffuse
rlam $fimx $dimx |rcalc -e '$1=$1+$2' > $imx2

echo -e "month\tday\ttime\tin_dir\tin_diff\tdir\tdiff\tdir+diff\tcomb" > $irr
tail -n +7 $WEA |rlam - $dimx $fimx $imx2 $cimx >> $irr

#EOF
---------------------8<-----------------------

There is absolutely no geometry at all--just the sky/suns. The final
resuls are stored under ./tmp/ in the file with the *.irr extension

here are the first few lines:

month    day    time    in_dir    in_diff    dir    diff    dir+diff    comb
1 1 0.500 0 0    0    0    0    0
1 1 1.500 0 0    0    0    0    0
1 1 2.500 0 0    0    0    0    0
1 1 3.500 0 0    0    0    0    0
1 1 4.500 0 0    0    0    0    0
1 1 5.500 0 0    0    0    0    0
1 1 6.500 0 0    0    0    0    0
1 1 7.500 0 0    0    0    0    0
1 1 8.500 0 19    6.01    6.01    12.02    6.01
1 1 9.500 7 51    16.6    16.6    33.2    16.6
1 1 10.500 17 88    28.2    28.2    56.4    28.2
1 1 11.500 22 109    34.8    34.8    69.6    34.8
1 1 12.500 22 110    35.2    35.2    70.4    35.2
1 1 13.500 17 91    29.2    29.2    58.4    29.2
1 1 14.500 4 56    18.2    18.2    36.4    18.2
1 1 15.500 0 6    2.14    2.14    4.28    2.14
1 1 16.500 0 0    0    0    0    0
...

What I am measuring is the horizontal unobstructed irradiance.

The first five columns are essentially the wea file:
month    day    time    in_dir    in_diff
to which the following have been laminated:
dir:  gendaymtx -5 -d; no sky, just 145 suns
diff:  gendaymtx -s; no suns, Tregenza patches, only diffuse contribution
dir+diff: dir + diff
comb: gendaymtx; no suns, Tregenza patches, diffuse and direct
contribution.  This is old skool for comparison.

I simply cannot make any sense of the results,  so I'm wondering
whether I am misunderstanding the concept behind the -5 option to
gendaymtx.

Take, for instance, this row:
1 1 8.500 0 19    6.01    6.01    12.02    6.01
There is no direct irradiance recorded in the wea file.  Yet, the
gendaymtx/rcontrib calculation produces 6.01 W/m2 (very low-angle
sun).
Also, I don't get why dir = diff = comb ???

I am probably using gendaymtx and rcontrib improperly, but have been
staring at this for quite a few hours now, without being able to work
out where I am making the mistakes.

Would anybody be able to offer assistance with this?

I have also tried doing the same think with genskyvec.  It doesn't
complain when I give it the -5 option, but the results are simularly
confusing.

Many thanks for your help

Best regards

Axel