[Radiance-general] What does "ray coefficient" mean?

[Ji Zhang]

Dear list, advices regarding the following questions are greatly
appreciated! - Ji


On Sun, Dec 29, 2013 at 12:04 AM, Ji Zhang <hope.zh at gmail.com> wrote:

> Dear List,
>
> May I ask what the "ray coefficient" means in the RCONTRIB man page?
>
> I'm going back to Axel Jacobs' tutorial on "rtcontrib(rcontrib now)":
>
> http://www.jaloxa.eu/resources/radiance/documentation/docs/rtcontrib_lesson.pdf
>
> and I tried the following with the *-ffa* option for rcontrib to see what
> is the output in ascii format:
>
>
>
>
> *vwrays -ff -x 600 -y 600 -vf ./views/back.vf \| rcontrib -ab 3 -ad 1024
> -ar 256 -aa .1 -ffa \ `vwrays -d -x 600 -y 600 -vf ./views/back.vf` -m
> sky_glow -n 2 -V+ \./testroom_overcast.oct > ./tmp/rcontrib-ffa.txt*
>
> The output contains the following:
>
>
>
>
>
>
>
>
>
>
>
> *#?RADIANCEoconv materials/testroom.mat objects/testroom.rad
> skies/sky_overcast.mat skies/sky.radrcontrib -ab 3 -ad 1024 -ar 256 -aa .1
> -ffa -x 600 -y 430 -ld- -m sky_glow -n 2 -V+ SOFTWARE= RADIANCE 4.2a
> lastmod Sat Jun 23 22:34:17 SGT 2012 by root on oats-iMac.localCAPDATE=
> 2013:12:28 23:54:10GMT= 2013:12:28 15:54:10FORMAT=ascii-Y 430 +X
> 6001.359378e-02    1.359378e-02    1.359378e-02    1.359378e-02
> 1.359378e-02    1.359378e-02   *
>
> *...*
> *(this continues for 258000 rows in total)*
>
> May I ask:
> 1. what the 3 values in each row represents for each pixel?
> 2. How is this function of rcontrib related to the calculation of daylight
> coefficient?
>
>
> *Thanks you all for your kind help and wish you all a happy new year!*
>
> - Ji
>
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