[Radiance-general] Help on BRTDfunc
Edilberto Calixihan
jcalixihan at cladding.com
Tue Oct 6 04:03:10 PDT 2009
Thanks Jack and Erick,
I got BRTDfunc to work on double glazing with glaze2.cal following the
previous post from Marija that:
void BRTDfunc double_glazing
10
if(Rdot,cr(fr(rf1_r),ft(t1_r),fr(rf2_r)),cr(fr(rb2_r),ft(t2_r),fr(rb1_r)))
if(Rdot,cr(fr(rf1_g),ft(t1_g),fr(rf2_g)),cr(fr(rb2_g),ft(t2_g),fr(rb1_g)))
if(Rdot,cr(fr(rf1_b),ft(t1_b),fr(rf2_b)),cr(fr(rb2_b),ft(t2_b),fr(rb1_b)))
ft(t1_r)*ft(t2_r)
ft(t1_g)*ft(t2_g)
ft(t1_b)*ft(t2_b)
0 0 0
glaze2.cal
0
9
0 0 0
0 0 0
0 0 0
Currently trying out glaze1.cal and hope that I get it right. Thanks for
the clues. I also reversed the window surface normal to point to the room
interior where my camera is. I may be able to modify the BRTDfunc and glaze
parameters thanks to your clues.
I was trying out various glass reflectance to see if it would affect the
rendered image and it did.
Thanks very much!
Best regards,
Jun
From: Jack de Valpine [mailto:jedev at visarc.com]
Sent: Monday, October 05, 2009 8:51 PM
To: jcalixihan at cladding.com; Radiance general discussion;
Erik.Moore at arup.com
Subject: Re: [Radiance-general] Help on BRTDfunc
Hi Jun and Erik,
To clarify a bit. The radiance material descriptions exported from Optics 5
are as follows:
* front side as BRTDfunc
* back side as BRTDfunc
* glass
The front and back descriptions use a simple version of BRTDfunc, simple in
that they do not call any functions for additional calculations that would
help account for angular dependencies for transmittance and reflectance.
However they do start to capture higher reflectance qualities of certain
types of glass. The glass material will account for the transmittance
(transmissivity) of the material but will not account for higher
reflectances and differing front and backside reflectances.
BRTDfunc is a full material in Radiance, thus like a glass, plastic, metal,
etc material type, it can be applied directly to geometry. The downside of
the BRTDfunc descriptions exported from Optics is that they do not account
for angular dependencies found in glazing materials for reflectance and
transmittance, to do this you need to do a bit more conversion. To have a
material description that integrates both front and back side
characteristics as well as accounts for angular dependencies, there are two
ways to go:
1. optics2rad - converts the radiance format file output from optics to
a more robust BRTDfunc material description.
2. glaze - look at the glaze script for building up material
descriptions for different types of glass. Note that this can be modified to
include data for other glass types that you may export from Optics (these
must be exported as single layers, not composites).
Hope this helps.
-Jack de Valpine
Edilberto Calixihan wrote:
Hello Erik,
Actually your reply was very helpful. It pointed me to where else to look
and think that BRTDfunc may be enough of a description.
My rendered picture looks the same as using the "glass" material though, and
it looks like I did not capture the glass reflectivity well. Anymore help
is very very welcome.
Cheers!
Best regards,
Jun
From: Erik Moore [mailto:Erik.Moore at arup.com]
Sent: Monday, October 05, 2009 6:36 PM
To: jcalixihan at cladding.com; Radiance general discussion
Subject: RE: [Radiance-general] Help on BRTDfunc
yeup, your correct. I should have had a bit more of a look before my
responce. As I previously said, I've never used the BRTDfunc material type
so I'm afraid I'm not any help with the use of the funcfile??
Anyone else?
_____
From: radiance-general-bounces at radiance-online.org
[mailto:radiance-general-bounces at radiance-online.org] On Behalf Of Edilberto
Calixihan
Sent: 05 October 2009 11:16
To: 'Radiance general discussion'
Subject: RE: [Radiance-general] Help on BRTDfunc
Hi Erik,
Thanks for giving some ideas on this and pointing in the right direction. I
was already stuck.
It seems BRTDfunc is already a material and we may not need the glass
material definition anymore (pls. correct me here).
Also it may seem that we may need to add the use of glazing.cal as mentioned
in http://finance.dir.groups.yahoo.com/group/DesktopRadiance/message/14. I
tried the below definition and it worked. Although I'm still not sure if
this is the correct way. Any additional clues is highly welcome.
void BRTDfunc Clear
10
0.077 0.082 0.082
0.857 0.894 0.877
0 0 0
glazing.cal
0
9 0 0 0 0 0 0 0 0 0
You're right on the same numbers of front and back reflectance from Optics 5
.rad file and will need to check the glass. I think Optics 5 may have a bug
on Radiance export but will verify:
http://www.radiance-online.org/radiance-workshop5/2006_Radiance_Workshop/Pre
sentations/Ward_RadianceFeatures.pdf
Thanks and best regards,
Jun
From: Erik Moore [mailto:Erik.Moore at arup.com]
Sent: Monday, October 05, 2009 4:47 PM
To: jcalixihan at cladding.com; Radiance general discussion
Subject: RE: [Radiance-general] Help on BRTDfunc
Hi there Jun,
I'm not an expert and I'm sure that someone might correct me but.... you
need to apply the modifier that you are using to the glass description. the
term 'void' means that you are not applying a modifier. Also, you will need
to change the name of the modifier (or the name of the polygons) as I think
that your polygons have been named 'clear'.
Try this:
void BRTDfunc 01_Clear_8_front
10
0.077 0.082 0.082
0.857 0.894 0.877
0 0 0
.
0
9 0 0 0 0 0 0 0 0 0
01_Clear_8_front glass clear
0
0
3 0.934 0.974 0.955
Please note the order.... Radiance will need to read what the modifier is
BEFORE it can be applied to anything. I have never used this sort of
modifier before, so I'm not too sure on what the arguments are (and hence
can't comment on them..??) and I'm not too sure why you have two of them
(front and back) which are identical?
hope this helps. Anyone else who can correct me on anything please but in!
Erik
_____
From: radiance-general-bounces at radiance-online.org
[mailto:radiance-general-bounces at radiance-online.org] On Behalf Of Edilberto
Calixihan
Sent: 05 October 2009 08:21
To: radiance-general at radiance-online.org
Subject: [Radiance-general] Help on BRTDfunc
Hello!
I'm new to Desktop Radiance and use Ecotect to create and run the
simulations. I need advise on using BRTDfunc. Below is the .rad file from
Optics 5 for the clear glass that I need:
void glass 01_Clear_8_glass
0
0
3 0.934 0.974 0.955
void BRTDfunc 01_Clear_8_front
10
0.077 0.082 0.082
0.857 0.894 0.877
0 0 0
.
0
9 0 0 0 0 0 0 0 0 0
void BRTDfunc 01_Clear_8_back
10
0.077 0.082 0.082
0.857 0.894 0.877
0 0 0
.
0
9 0 0 0 0 0 0 0 0 0
When I insert it into the my scene file (replace the default glass command
lines) I get an "unidentified modifier "Clear"" error. Which means the
polygons referencing "Clear" cannot find the glass description, right? I
would modify the glass description to various id combinations like the one
below but I get a "bad arguments for "Clear"" error.
void glass Clear Clear_8_glass
0
0
3 0.934 0.974 0.955
void BRTDfunc Clear_8_front
10
0.077 0.082 0.082
0.857 0.894 0.877
0 0 0
.
0
9 0 0 0 0 0 0 0 0 0
void BRTDfunc Clear_8_back
10
0.077 0.082 0.082
0.857 0.894 0.877
0 0 0
.
0
9 0 0 0 0 0 0 0 0 0
How can I properly run BRTDfunc and the glass reflection numbers from Optics
5?
The one that seems to run ok is below but not sure if I got it right..
Also, we don't have a Unix pc at work but I'm interested in the newer
versions of Radiance. Shall I start to learn Cygwin or MinGW to access
advance glass functions? Any advice would be very helpful.
void glass Clear
0
0
3 0.934 0.974 0.955
void BRTDfunc Clear_8_front
10
0.077 0.082 0.082
0.857 0.894 0.877
0 0 0
.
0
9 0 0 0 0 0 0 0 0 0
void BRTDfunc Clear_8_back
10
0.077 0.082 0.082
0.857 0.894 0.877
0 0 0
.
0
9 0 0 0 0 0 0 0 0 0
Thanks so much!
Jun
____________________________________________________________
Electronic mail messages entering and leaving Arup business
systems are scanned for acceptability of content and viruses
_____
_______________________________________________
Radiance-general mailing list
Radiance-general at radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general
--
# Jack de Valpine
# president
#
# visarc incorporated
# http://www.visarc.com
#
# channeling technology for superior design and construction
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://radiance-online.org/pipermail/radiance-general/attachments/20091006/1cd0e36a/attachment-0001.html
More information about the Radiance-general
mailing list