[Radiance-general] can the sun material identifier "solar" be specified in rcontrib?

[Ji Zhang]

Thanks, Jack! seems I need to working on the tutorial a bit more before I
raise the question ...


On Mon, Dec 30, 2013 at 10:20 PM, Jack de Valpine <jedev at visarc.com> wrote:

>  Hi Ji,
>
> If you keep working through Axel's tutorial, you will see that the
> distribution for a given sky condition is applied as a separate step using
> output from gensky or gendaylit piped into genskyvec. Rtcontrib is being
> used to calculate the skypatches for a unit/uniform distribution. These
> unit results are then multiplied by the output from the genskyvec command.
> So the actual output/distribution for a given sun/sky is not part of the
> rtcontrib calculation.
>
> Hope this helps,
>
> -Jack
>
> --
> Jack de Valpine
> President
>
> Visarc Incorporatedwww.visarc.com
>
> channeling technology for superior design and construction
>
> On 12/30/2013 7:50 AM, Ji Zhang wrote:
>
>  Dear list,
>
> Following Axel Jacobs' Rtcontrib tutorial (up to pp.19 so far), I used a
> sky created by gendaylit rather than an overcast/uniform sky used in the
> tutorial.
>
>  The hdr image i got by combining the 145 sky patch hdr images shows a
> dark spot around the sun position. I assume this might be because only the
> "-m sky_glow" argument is specified in rcontrib, thus the image generated
> doesn't include the contribution from the sun spot.
>
>  However, when I include an additional "-m solar" argument (the material
> identifier for the sun geometry) to the rcontrib command I only got strange
> sky patch images.
>
>  May I ask why this approach is not correct? and how to visualize the
> contribution from the sun spot?
>
>  Thanks!
>  Ji
>
>
>
>  The shell script (without sun material identifier):
> ##############################
>  # create a sky description using gendaylit
>
>  gendaylit  1 1 9 -a 1.37 -o -103.98 -m -120 -W 70.0 130.0 -O 1 >
> ./skies/sky_gendaylit.rad
>
> # copy all lines in the original sky.rad and past in the newly generated
> sky_gendaylit.rad above
>
> oconv ./materials/testroom.mat ./objects/testroom.rad
> ./skies/sky_gendaylit.rad > testroom_gendaylit.oct
>
> # viz the contribution from each of the 145 patches in the gendaylit sky
> from the fisheye viewpoint
>
> DIMS=600
>
> vw="-x $DIMS -y $DIMS -vf ./views/sky.vf"
>
> vwrays -ff $vw | rcontrib -bn 146 @./rtc.opt -ffc \
> `vwrays -d $vw` -V+ -f tregenza.cal -b tbin \
> -o ./images/patches_gendaylit_skyview/p%03d.hdr \
> -m sky_glow ./testroom_gendaylit.oct
>
> # use Andy McNeil's approach to merge the 145 hdr images
>
> pcomb $(for i in {001..145}; do \
> echo "./images/patches_gendaylit_skyview/p$(printf "%03d" $i).hdr"; done) \
> > ./images/sky_pcomb_gendaylit_skyview.hdr
>
> falsecolor -ip ./images/sky_pcomb_gendaylit_skyview.hdr -s 10000 -l cd/m2
> -n 10 \
> > ./images/sky_pcomb_gendaylit_skyview_fc.hdr
> ##############################
>
>
>
> The shell script of rcontrib with the sun material identifier included:
> ##############################
> vwrays -ff $vw | rcontrib -bn 146 @./rtc.opt -ffc \
> `vwrays -d $vw` -V+ -f tregenza.cal -b tbin \
> -o ./images/patches_gendaylit_backview_withSun/p%03d.hdr \
> -m sky_glow -m solar ./testroom_gendaylit.oct
> ##############################
>
>
>
>
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