[Radiance-general] Heavily different sensor values with different (rcontrib?) versions

[Andy McNeil]

Stefan,

The only major change to rcontrib I know of was the addition of extra
details in the header, but you're not writing the header so that can't be
the problem. The only thing I can think of is that there are some
differences in shell tools between BSD and Linux, so perhaps test seq and
tr independently to make sure they are doing what you expect. Other than
that I don't know what could be happening.

Now that you're using a recent version of Radiance instead of the for loop
you could use a single inline rmtxop command like this:

cat $sensors | rcontrib -I -fo @scene.opt -ab 4 -ad 100000 -lw 0.000004 -y
$numsensors -e MF:1 -f reinhart.cal \
    -b rbin -bn Nrbins -m sky_glow -w scene.oct | rmtxop -c 0.265 0.67 0.065
- > $sensors_vec

just make sure you define $numsensors as your number of sensors.

As for settings to consider, if you're interested in specular reflections
you probably want to set -st 0. And you'll probably need to reduce -lw
further to something lower than your facade reflectance divided by ad
setting. For example, if your facade VLT is 5% it would have to be less
than 0.05/100000=0.0000005 or 5e-7 (you currently have 4e-6).

Best,
Andy






On Mon, May 23, 2016 at 5:32 AM, Stefan Bohren <stefan.bohren at stud.unibas.ch
> wrote:

> Dear Radiance community
>
> I am doing my master thesis about the relevance of reflections on solar
> fassades, for what I want to make some simulations with radiance, and also
> testing it with a little live experiment.
>
> After having worked myself through most radiance tutorials and the book
> (very helpful), my prof helped me to put a script together, which in the
> end should be able to return radiation values at several sensor points, and
> opt on different ambient settings, surfaces and sensor point locations.
>
> And now where we are stuck atm: His results with the script are reasonable
> (on OSX 10.9, likely with radiance 4.1), but if I use exactly the same
> script and files (on Ubuntu 16 with newest radiance), I get values that are
> far away from realistic (three to ten times too high radiation values, and
> slightly different to physically impossible rgb-tripplets), without any
> error messages. I searched through the archive, but didn't find a similar
> issue.
>
> As the results of gendaylit -> genskyvec are identical, I think the
> problems are starting with rcontrib, which we use to produce the sensor
> radiation readings for each sky patch:
>
>   cat $sensors |rcontrib -h -I -fo @scene.opt -ab 4 -ad 100000 -lw
> 0.000004 -e MF:1 -f reinhart.cal \
>     -b rbin -bn Nrbins -o results/p%04d.dat -m sky_glow -w scene.oct
>
> and are getting worse where we set them all together:
>
>   for i in $(seq -f "%04g" 0 145); do
>     cat results/p${i}.dat |rcalc -e '$1=($1*0.265+$2*0.67+$3*0.065)' |tr
> '\n' '\t' >> $sensors_vec
>     echo >> $sensors_vec
>   done
>
> As the results are fine with the older version, and not the other way
> around, we'd really be happy if you helped us on how to adapt the script to
> the current radiance version - or told us if  we are doing something
> completely wrong!
>
> Looking ahead this issue, we also are wondering which will be the
> important ambient settings to optimise, in the end it will be a large
> (several buildings) outdoor setting, and I'd be glad if you could hint me
> into the right direction with that as well!
>
> Thank you very much,
> Stefan
>
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>
>
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