Hi Ben,
I should know, but I don't. Does the Window 5 program output colored materials for Radiance? Maybe Judy knows. (Judy?)
The names of the colors don't really help, much. You need either spectral transmittance and reflectance values or (at least) CIE (x,y) chromaticities for each transmitted and reflected color. I can't get these values from the names. Perhaps Window 5 can??
Other help!
-Greg
···
From: "Ben Masters" <[email protected]>
Date: Thu Oct 9, 2003 1:38:48 PM US/Pacific
To: [email protected]
Hi Greg,
Hopefully you can help me. I am using Radiance to model a series of coloured glass panels on a building. We have chosen each glass type from the Window 5 program. I will be using Radiance to produce both colour rederings and for numerical daylight factor output.
I understand how to realistically model the glass using just the transmittance value of each glazing type. How do I exactly match the colour of each glazing type by specifying each RGB colour? The glass colours will be critical to give a realistic image.
Here are the glass types I will be modelling:
From the G. James range.
Sea spray
Aqueous
Island Sea
Oceanic
Atlantis
Outer Reef
Pacific Sky
Thanking you in advance,
Ben Masters
Auckland, New Zealand
Hi Ben and Greg,
I am by no means a glazing expert but I think that the best bet so far for glazing color based on measured data is to use Optics 5 from LBNL. This is a sister product to Window 5 and in fact Window 5 relies on the optical property data produced by Optics 5 for its glazing database and calculations. With Optics 5 you can build up your glazing system and then export it in a number of formats including to Radiance. The underlying data for the program is measured spectral transmittance and reflectance. For Radiance it will export 3 material definitions, which you need to choose from when assigning to geometry. There is the simple glass type and then there is a front and back BRTDfunc that gets exported. The latter specifically assigns the specular reflectance and transmittance for the material (although I do not know if this is calculated based on normal incidence or over the hemisphere). I think the BRDTfunc is probably the way to go for looking at glass on the outside of a building. But this is a very simple use of this very powerful material type and as Greg can much more ably explain it still does not account for any angular dependance/interaction in the material.
Perhaps some others with Optics 5 and Radiance experience would like to chip in their two cents as well? Also depending on how dirty you want to get your hands, there is something called glaze.csh which Greg put together for us a while ago. I believe this was released in the Radiance 3.5. This computes a more sophisticated BRTDfunc glazing material. But it would need to be modified for the relevant reflectance/transmittance data that you are interested in, which would still need to be derived from Optics 5 as I recall.
Regards,
-Jack de Valpine
PS: Apologies to the Window 5 and Optics 5 team, I have not really done a great job explaining the relation of the tools to each other and there respective features. Again if someone wants to chip in a more robust explanation this would be great!
Greg Ward wrote:
···
Hi Ben,
I should know, but I don't. Does the Window 5 program output colored materials for Radiance? Maybe Judy knows. (Judy?)
The names of the colors don't really help, much. You need either spectral transmittance and reflectance values or (at least) CIE (x,y) chromaticities for each transmitted and reflected color. I can't get these values from the names. Perhaps Window 5 can??
Other help!
-Greg
From: "Ben Masters" <[email protected]>
Date: Thu Oct 9, 2003 1:38:48 PM US/Pacific
To: [email protected]
Hi Greg,
Hopefully you can help me. I am using Radiance to model a series of coloured glass panels on a building. We have chosen each glass type from the Window 5 program. I will be using Radiance to produce both colour rederings and for numerical daylight factor output.
I understand how to realistically model the glass using just the transmittance value of each glazing type. How do I exactly match the colour of each glazing type by specifying each RGB colour? The glass colours will be critical to give a realistic image.
Here are the glass types I will be modelling:
From the G. James range.
Sea spray
Aqueous
Island Sea
Oceanic
Atlantis
Outer Reef
Pacific Sky
Thanking you in advance,
Ben Masters
Auckland, New Zealand
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# president
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# visarc incorporated
# http://www.visarc.com
#
# channeling technology for superior design and construction
hi Greg, Ben,
I don't believe windows 5 can output colored materials for Radiance, maybe you are thinking of Optics 5? There's an option in Optics5 to export a radfile of whatever glazing you chose. You can get Optics5 here.
http://windows.lbl.gov/materials/optics5/default.htm
You want to compare the glazing types from looking from outside?
In that case I think you'll have to use the BRTDfunc "front" material.
hope that helps...
.
judy
Greg Ward wrote:
···
Hi Ben,
I should know, but I don't. Does the Window 5 program output colored materials for Radiance? Maybe Judy knows. (Judy?)
The names of the colors don't really help, much. You need either spectral transmittance and reflectance values or (at least) CIE (x,y) chromaticities for each transmitted and reflected color. I can't get these values from the names. Perhaps Window 5 can??
Other help!
-Greg
From: "Ben Masters" <[email protected]>
Date: Thu Oct 9, 2003 1:38:48 PM US/Pacific
To: [email protected]
Hi Greg,
Hopefully you can help me. I am using Radiance to model a series of coloured glass panels on a building. We have chosen each glass type from the Window 5 program. I will be using Radiance to produce both colour rederings and for numerical daylight factor output.
I understand how to realistically model the glass using just the transmittance value of each glazing type. How do I exactly match the colour of each glazing type by specifying each RGB colour? The glass colours will be critical to give a realistic image.
Here are the glass types I will be modelling:
From the G. James range.
Sea spray
Aqueous
Island Sea
Oceanic
Atlantis
Outer Reef
Pacific Sky
Thanking you in advance,
Ben Masters
Auckland, New Zealand
Actually, when developing the Radiance material output specifications for Optics 5, I defined the "front" material as the glazing surface that faces the "inside" of the building. So, for accurate color rendition from the outside, use the "back" material.
I haven't looked at the output for a while, but I think there is also a skeletal material definition for a BRTDfunc version of the glazing.
-Chas
···
========
Date: Thu, 09 Oct 2003 15:17:57 -0700
From: judy lai <[email protected]>
To: Greg Ward <[email protected]>
CC: Ben Masters <[email protected]>, [email protected]
Subject: [Radiance-general] Re: Realistic glass colours
Reply-To: [email protected]
hi Greg, Ben,
I don't believe windows 5 can output colored materials for Radiance,
maybe you are thinking of Optics 5? There's an option in Optics5 to
export a radfile of whatever glazing you chose. You can get Optics5 here.
http://windows.lbl.gov/materials/optics5/default.htm
You want to compare the glazing types from looking from outside?
In that case I think you'll have to use the BRTDfunc "front" material.
hope that helps...
.
judy