[Radiance-general] modeling external glass lamella incl discription of trans data

[Anne Iversen]

Hi Rob and Greg,
Thanks for your answers!
I have carried out simulations with two different definitions of trans, but
I get the same result for each type of trans. For both approaches, when
checking the material under a glow sky, I get the reflectance 0.31 when
looking down on the glass and I get the transmittance 0.65 when looking in
the direction upwards.

I have listed my discription of trans below - looking forward to hearing
your comments.

Br
Anne


The trans data is defined as:
# a1, a2 og a3 = 1, due to the color of the glass is included in the
transmittance end reflectance given by the manufacturer
# a4 = 0,31
# a5 = 0
# a6 = trans, determined from t_s=a6*a7(1-a4), where t_s is 0.65 and a7=1
# a7 = 1

void trans lamel_trans
0
0
7  1 1 1 0.31 0 0.942028986 1

I have also tried to define my trans material according to the description
in http://www.schorsch.com/rayfront/manual/transdef.html.
#Spec=Light reflectance = 0.31
#The color of the glass is determined from:
#Absorptance=(1-spec)(1-color) -> 0.04 = (1-0.31)(1-color), from where the
color is found to be 0.94
#Transmittance = (1-spec) *color* trans, transmittance is 0.65 and trans can
then be found to be 1
#Rough is set to 0, as the material is glass
#Tr-spec is set to 1, as the glass is a clear glass material



void trans lamel_transrayfront
0
0
7  0.94 0.94 0.94 0.31 0 1 1
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