[Radiance-general] 5-phase method model reflectance

[Andrew McNeil]

The direct sun coefficient matrix only includes materials in your window
system, assuming you're using pass-through BSDF in you model. So it
shouldn't change when you change other materials. Maybe check that your
materials are actually black using rvu?

There are ways to reduce the amount of time the direct sun coefficient
matrix takes, the most useful is to delete the suns in suns.rad that will
never be used. So if you don't plan on changing the orientation or latitude
in your simulations you can delete suns that fall outside of your solar
band. Also if you're only doing hourly analysis, you could delete suns
between hourly analemas.


On Wed, Jun 17, 2015 at 9:56 AM, Eleonora Brembilla <E.Brembilla at lboro.ac.uk
> wrote:

>  Dear All
>
>  I am doing some analyses on reflectance values and I have just started
> using the 5-phase method for those.
>
>  At first I thought the reflectances assigned to the model would not
> matter for the part that is specific to the 5-phase, as the model is
> assigned a black material, but comparing the resulting matrices it looks
> like the Sun Coefficient Matrix (.dsc) changes with the original materials’
> reflectances (and it’s the only matrix that change). And that is exactly
> the matrix that is taking most of the computational effort (about 4 hours I
> think - the same model with the 2-phase method takes 5 minutes, glazing is
> all simple clear glass).
>
>  5pm_dsc.opt:     -ab 1 -ad 50000 -as 0 -lw 2e-5 -dc 1 -dt 0 -dj 1 -st 1
> -ss 0
>
>
>   rfluxmtx -n 4 -faa -I+ @5pm_dsc.opt -y `wc -l < $prj.pts` < $prj.pts -
> skies/suns.rad $pmats/materials-$i.rad $prj-black.rad windows.rad >
> dmx/MF6.dsc
>  oconv $pmats/materials-$i.rad $prj-black.rad windows.rad skies/suns.rad
> > octs/model_suns-$i.oct
>  rcontrib -n 4 -I+ @5pm_dsc.opt -faa -e MF:6 -f reinhart.cal -b rbin -bn
> Nrbins -o dmx/MF6-$i.dsc -m solar octs/model_suns-$i.oct < $prj.pts
>
>
>  Am I doing something wrong or is this the normal behaviour? The data I
> get in the end are plausible. Could you explain why the Sun Coefficient
> Matrix needs to take into account the model reflectances at all?
>
>  I hope I managed to explain the issue somehow... Thanks for your help!
>
>  Eleonora
>
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