[Radiance-general] glaze script limitation
Jack de Valpine
jedev at visarc.com
Wed Dec 15 08:59:35 PST 2010
Hi Francois,
As Greg pointed out, using different clear glass specifications for each
layer would really complicate things. Note the "clear" glass
specification is really to establish a default reflectance and
transmittance for the uncoated faced in the system. Color, Rf, Rb and
Transmittance are derived from the other specifications (eg for SunGuard
Ag 43 or SunGuard SN 62) in this case. Have you tried defining a
material based on the exported data from Optics?
Here is what I did:
Export individually from Optics:
SGAG43Y6.grd (3156)
SGSN62C6.grd (3116)
Clear_60.GRD (3016)
Then get photopic T, Rf and Rb for reference from Optics 5 for the whole
IGU:
Rf = .178
Rb = .107
T = .228
Note that the script (optics2glazedb) is very strict on formatting. So
the naming in Clear_60.rad:
Clear_60_glass
Clear_60_front
Clear_60_back
needs to have the first "_" removed to result in:
Clear60_glass
Clear60_front
Clear60_back
I suppose this could easily enough be fixed with a call to awk or perl
to fix this type of thing on the fly.
Now with Clear_60 fixed do:
optics2glazedb Clear_60.rad SGAG43Y6.rad SGSN62C6.rad > francois.db
Now run glaze:
glaze -f francois.db
build a 2 pane system as follows:
1. Clear60
2. SGAG43Y6
3. SGSN62C6
4. Clear60
This results in the following definition:
############################################
# Glazing produced by Radiance glaze script
# $Revision: 2.8 $
# Loaded: francois.db
# Wed Dec 15 11:14:23 EST 2010
# Material surface normal points to interior
# Number of panes in system: 2
# Exterior surface s1 type: Clear60
# Inner surface s2 type: SGAG43Y6
# Inner surface s3 type: SGSN62C6
# Interior surface s4 type: Clear60
# Exterior normal hemispherical reflectance: 0.177978104
# Interior normal hemispherical reflectance: 0.108662425
# Normal hemispherical transmittance: 0.225458181
#
void BRTDfunc francois
10
if(Rdot,cr(fr(0.052),ft(0.664),fr(0.083)),cr(fr(0.145),ft(0.295),fr(0.036)))
if(Rdot,cr(fr(0.076),ft(0.708),fr(0.067)),cr(fr(0.177),ft(0.339),fr(0.076)))
if(Rdot,cr(fr(0.11),ft(0.604),fr(0.162)),cr(fr(0.211),ft(0.333),fr(0.113)))
ft(0.664)*ft(0.295)
ft(0.708)*ft(0.339)
ft(0.604)*ft(0.333)
0 0 0
glaze2.cal
0
9
0 0 0
0 0 0
0 0 0
Although I am not sure what kind of rounding error is acceptable in this
case, the hemispherical front/back reflectances and transmittance seem
to be well in the ballpark. If you want to go further you can look at
color, reflectance, and transmittance with a simple scene using a glow
source with unit radiance (eg 1 1 1). Doing this yields measures as
follows:
Rf = .181
Rb = .109
T = .227
So here is what we get in summary:
Optics Calculated
Radiance Glaze Calculated
Radiance Rpict Measured
Rf
.178
.178
.181
Rb
.107
.109
.109
T
.228
.225
.227
A further piece of information that might be interesting is to obtain
the manufacturers calculated photopic Rf, Rb, and T for the system. I
have noticed that there can be small discrepancies between performance
data on sites and what Optics calculates.
I hope this helps.
Regards,
-Jack de Valpine
--
# Jack de Valpine
# president
#
# visarc incorporated
# http://www.visarc.com
#
# channeling technology for superior design and construction
On 12/14/2010 5:47 PM, François Cantin wrote:
>
> Hi everyone,
>
> I would like to model a double glazing system like the following:
>
> first pane
>
> surface 1: Crystal gray (Optics database number: 3056)
>
> surface 2: Crystal gray with a SunGuard Ag 43 coating (Optics: 3156)
>
> second pane
>
> surface 3: Clear glass with a SunGuard SuperNeutral (SN) 62 coating
> (Optics: 3116)
>
> surface 4: Clear glass (Optics: 3016)
>
> Using the Optics2glazedb script provided by Jack de Valpine, I'm able
> to create a custom database which contain all of the above
> surfaces/layers and can be read by the Glaze script.
>
> However, the Glaze script, used to combine the surfaces and generate a
> usable material definition, force the user to select at least one
> clear glass to compose each pane (surface 1 or 2 must be clear AND
> surface 3 or 4 must be clear). Moreover, the clear glass must be the
> same for both panes and must be the first one on the list provided
> when running the Glaze script.
>
> My question is:
>
> If I bypass the ''if structures'' constraining the composition of the
> panes in order to allow the selection of two different uncoated glass,
> can I expect the output to be still valid ?
>
> /.../
>
> /#if ($s1t != 1 && $s2t != 1) then/
>
> / #echo "One surface of each pane must be $sn_arr[1]"/
>
> ///#exit 1/
>
> /#endif/
>
> /.../
>
> //
>
> //
>
> /.../
>
> /#if ($s3t != 1 && $s4t != 1) then/
>
> / #echo "One surface of each pane must be $sn_arr[1]"/
>
> ///#exit 1/
>
> /#endif/
>
> /.../
>
> Without such bypass, generating a glazing system like the one
> described above seems impossible.
>
> Thanks in advance for your help,
>
> _____________________________________________________________
>
> *François Cantin, M Arch, MSc Arch
> *
> *Hudon Julien* associes,
>
> 1175 Lavigerie, suite 400, Ste-Foy(Québec) G1V 4P1
> Tél: (418) 653-8484 #224, Fax:(418) 653-6189
> E-mail: fcantin at hudonjulien.com <mailto:fcantin at hudonjulien.com>
> Site web: www.hudonjulien.com <http://www.hudonjulien.com/>
>
> *P**Avant d'imprimer, pensez à l'environnement*
>
> /Ce message électronique et tous les fichiers attachés qu'il contient
> sont confidentiels et destinés exclusivement à l'usage de la personne
> à laquelle ils sont adressés. Si vous avez reçu ce message par erreur,
> merci de le retourner à son émetteur. La publication, l'usage, la
> distribution, l'impression ou la copie non autorisée de ce message et
> des attachements qu'il contient sont strictement interdits.
>
> //This e-mail and any files transmitted with it are confidential and
> intended solely for the use of the individual to whom it is addressed.
> If you have received this email in error please send it back to the
> person that sent it to you. Unauthorized publication, use,
> dissemination, forwarding, printing or copying of this email and its
> associated attachments is strictly prohibited./
>
>
> _______________________________________________
> Radiance-general mailing list
> Radiance-general at radiance-online.org
> http://www.radiance-online.org/mailman/listinfo/radiance-general
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.radiance-online.org/pipermail/radiance-general/attachments/20101215/0c8c58a5/attachment-0001.html>
More information about the Radiance-general
mailing list