Hi,
I have a question concerning the definition of "glass" material. I am
trying to determine the transmittance of a window pane using spectrum
measurements.
I have derived the following values for rgb (0.78, 0.85, 0.80).
-Are those values determining transmittance or transmissivity?
-Can the transmittance be derived using the formula Tn = 0.265r + 0.67g +
0.065b ?
_Nicolas
Hi,
I have a question concerning the definition of "glass" material. I am trying
to determine the transmittance of a window pane using spectrum measurements.I have derived the following values for rgb (0.78, 0.85, 0.80).
-Are those values determining transmittance or transmissivity?
Radiance expects transmissivity
-Can the transmittance be derived using the formula Tn = 0.265r + 0.67g + 0.065b ?
No. The formula is
Tn = (sqrt(0.8402529435+0.0072522239*t*t) - 0.9166530661) / 0.0036261119 / t
where t = transmittance and Tn = Transmissivity
Sorry for the format. I have copied it from a python script. Best thing I could
do in plain text.
I have a PDF document where this is further detailed. I just can't find it or
it's source on the web.
Regards,
Thomas
On 20 Nov 2007, at 10:36, Nicolas Roy wrote: