[Radiance-general] modelling reflections from surrounding buildings

[Thomas Bleicher]

Hello Christoph.

I don't quite understand how you want to create a "reflected" sun without
knowing the position and orientation of the reflecting window. And if you do
know that why don't you just use a "mirror" material for this window which
will create the reflected sun for you?

Anyway, back to creating a second sun:

On Wed, Aug 11, 2010 at 3:36 AM, Christoph Begert - SBE <
Christoph.Begert at sbe.com.au> wrote:

I was thinking of adding another line into my sky file, however am not
> totally sure how to exactly do this and was hoping that someone here could
> help me with this.
>

If you look at the output of a gensky command for skies with sun ("+i" or
"+s" option) you will find the definition for the sun; something like this:

void light solar
0
0
3 6.92e+06 6.92e+06 6.92e+06

solar source sun
0
0
4 0.067845 -0.617210 0.783868 0.5

The definition of "solar" defines the intensity of the sun which you have to
modify according to the reflection of the glazing.

The second block creates the actual sun with the first 3 parameters as
direction vector. This vector needs to be modified by "reflecting" it on the
plan of the reflecting window. You should be able to find the math for the
that on the internet.

The fourth parameter is the size of the sun (in degrees) and can probably
stay unchanged.


Regards,
Thomas
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