[Radiance-general] Irradiation on standing subject with Radiance

[Ruggiero Guida]

Thanks a lot for your help Greg,

Yes, my samps.txt has exactly 105 lines with point and direction.

When I run your command

rcontrib -c 105 -y 1 -I+ -f tregenza.cal -m groundglow -b tbin -bn 145 -m
skyglow test.oct < samps.txt > daycoef.mtx

I get a daycoef.mtx with the correct number of elements of which only the
first is not zero. Am I missing something? I have double check the sky and
ground file and they are correct.

Thanks again
Ruggiero





On Thu, 3 Mar 2016 at 20:26 Greg Ward <gregoryjward at gmail.com> wrote:

> Hi Ruggiero,
>
> As given, your command:
>
> rcontrib -c 105 -I+ -f tregenza.cal -m skyglow -m groundglow test.oct <
> samps.txt > daycoef.mtx
>
> does average 105 irradiance positions, taken them in sequence from
> samps.txt.  I assume this contains exactly 105 random sample positions &
> directions.
>
> The output will not be Tregenza sky patches, because you are missing some
> needed options.  If you want your ground average to precede your 145
> Tregenza patches in your matrix, then use the following order:
>
> rcontrib -c 105 -y 1 -I+ -f tregenza.cal -m groundglow -b tbin -bn 145 -m
> skyglow test.oct < samps.txt > daycoef.mtx
>
> The above process can in fact be simplified by merging your ground.rad and
> sky.rad files with some comments like so:
>
> <combined_sky.rad>
> # Combined ground and sky vault for calculating cylindrical irradiance
>
> # Start by telling rfluxmtx to generate a single coefficient for the
> ground:
> #@rfluxmtx h=u
>
> void glow groundglow
> 0 0 4 .8 1.1 .8  0
> groundglow source ground
> 0 0 4 0 0 -1  180
>
> # Now, tell rfluxmtx to generate a set of Tregenza sky patches using Y for
> "north/up":
> #@rfluxmtx h=t u=+Y
>
> void glow sky_glow
> 0 0 4    1 1 1 0
> sky_glow source sky
> 0 0 4    0 0 1 180
>
> ------------------
> Notice how I took out the actual sky distribution, which you don't need
> for a coefficient calculation.  (It would make no difference to the results
> in fact.)
>
> Then, you can then use rfluxmtx to call oconv and rcontrib for you:
>
> rfluxmtx -c 105 -y 1 - combined_sky.rad < samps.txt > daycoef.mtx
>
> Note that the lone hyphen ("-") tells rfluxmtx to read from its standard
> input, and must be given as shown above.  Assuming you have just 105
> positions  in samps.txt, I've specified -y 1, so that the output matrix has
> both its dimensions set properly.
>
> Once you have the above matrix, you can multiply it against any sky vector
> to get the desired cylindrical irradiance:
>
> gendaylit [options] | genskyvec | dctimestep daycoef.mtx
>
> The above command should produce a single RGB triplet corresponding to the
> cylindrical irradiance with the given sky.
>
> Cheers,
> -Greg
>
> *From: *Ruggiero Guida <ruggiero.guida at gmail.com>
>
> *Subject: *Re: [Radiance-general] Irradiation on standing subject with
> Radiance
>
> *Date: *March 3, 2016 12:35:35 AM PST
>
>
> Hi Greg,
>
> I finally managed to have a look at this problem again.
>
> To begin with I was starting with a basic case: just sky and ground.
>
> <sky.rad>
> void light solar
> 0 0 3 5.326e+06 5.326e+06 5.326e+06
>
> solar source sun
> 0 0 4 0.463565 0.022184 0.885785 0.533000
>
> void brightfunc skyfunc
> 2 skybright perezlum.cal
> 0 10 5.802e+01 4.447e+01 -0.843574 -1.078181 11.876231 -3.091220 0.271617
> 0.463565 0.022184 0.885785
>
> skyfunc glow sky_glow
> 0 0 4    1 1 1 0
> sky_glow source sky
> 0 0 4    0 0 1 180
>
> <ground.rad>
> skyfunc glow groundglow
> 0 0 4 .8 1.1 .8  0
> groundglow source ground
> 0 0 4 0 0 -1  180
>
> I then generate the scene with
>
> oconv materials.rad sky.rad ground.rad > test.oct
>
> Let's suppose I want to calculate the contributions on the subject from a
> tregenza subdivision I would use
>
> rcontrib -c 105 -I+ -f tregenza.cal -m skyglow -m groundglow test.oct <
> samps.txt > daycoef.mtx
> This is my understanding of this command.
>
> 1 - For each of the 105 random points
> 2 - create a tregenza dome subdivision
> 3 - calculate all the contributions from groundglow and skyglow and add
> them up (this considers the cosine between the normal of the point and the
> patch vector)
> 4 - finally average all the results for the 105 points.
>
> Does this make any sense? How would I obtain the actual matrix?
>
> Thanks
> Ruggiero
>
> _______________________________________________
> Radiance-general mailing list
> Radiance-general at radiance-online.org
> http://www.radiance-online.org/mailman/listinfo/radiance-general
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.radiance-online.org/pipermail/radiance-general/attachments/20160304/6fc6b3ec/attachment-0001.html>