[Radiance-general] Asking for informations

[Germán Molina Larrain]

>From my understanding,

   1. -O0 will give you a Perez Sky... similar to the Gensky output, but
   using a diferent sky model. This model does not need to be told if the sky
   is overcast or clear. It will figure that out itself.
   2. -O1 will give you the Perez Sky but with for the solar spectrum (i.e.
   solar radiation calculation)
   3. -O2 is something that I wonder why is there.

If you want your output on Watts (or any energy unit), you should use a
multiplier of 1. For Lighting units (lux, cd, lumens) you need a multiplier
of 179.....I do not usually make pictures... but I hope the few I have done
were correct.

Best.

2016-04-14 8:21 GMT-03:00 Terrance McMinn <t.mcminn at ocpms.com.au>:

> Follow up question:
>
> Using gendaylit rather than the gensky sky generator we have additional -O
> options. -O 1 for W/m^2/sr solar radiation.
>
>
> *From the gendaylit man page: The output can be set to either the radiance
> of the visible radiation, the solar radiance (full spectrum) or the
> luminance. **-O**[0|1|2] (0=output in W/m^2/sr visible radiation
> (default), 1=output in W/m^2/sr solar radiation, 2=output in lm/m^2/sr
> luminance).*
>
> Looking at the source code it appears the -O 0 option divides illuminance
> by 179 whilst the -O 1 and -O 2 don't. I couldn't see how the units are
> outputted from gensky (in relation to the 179 multiplier) to allow me to
> compare it to the gendaylit options.
>
> One might assume that the -O 0 option would be set to similar units as the
> gensky generator.
>
> From this confusion what multiplier should be used with the falsecolor
> program when using gendaylit options 0, 1 and 2 remembering that falsecolor
> has the default -m 179?
>
> (I all cases I would be using the rpict -i option and looking for units in
> W/m^2)
>
> Regards
> *Terrance McMinn*
>
> On 8/04/2016 10:27 am, Terrance McMinn wrote:
>
> Thank you Chris.
>
> From an irradiance image (-i) I didn't realise a multiplier of 1 in
> falsecolor provided units in W/m2
>
> I accept the reservations. For this project a gross mapping over a large
> site with block building shapes, the results can only be construed as
> indicative.
>
> Regards
> *Terrance McMinn*
>
> Yes, there is a -m multiplier option to falsecolor, which defaults to
>    -m 179    and should equate to lux or cd/m². Luminance in cd/m2 is the
> default label to display luminance unless you give the   -l lux     option
> for example for illuminance – both related to the 179 lumen/Watt multiplier.
>
>
>
> However for Watts you can use    -m 1    in your options to falsecolor
> along with    -l W/m2    to change the label to display as W/m2. That is
> presuming your image is calculated with -i option for irradiance. I don’t
> think people would normally expect to see a Watts based radiance image in
> W/sr/m2.
>
>
>
> This is also presuming the intent of your image takes into account all the
> shortcomings that Achim noted.
>
>
>
> *From:* Terrance McMinn [mailto:t.mcminn at ocpms.com.au
> <t.mcminn at ocpms.com.au>]
> *Sent:* Thursday, April 07, 2016 9:39 AM
>
> Can you configure falsecolor to map as w/sqm?
>
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