[Radiance-general] Modelling glass lamellas in Radiance.

[Gregory J. Ward]

Hi Jacob,

It's difficult to answer your question without knowing anything about  
IESve or what it permits.  You also didn't specify what you mean by  
"glass blinds."  Is this just a window with some odd coating(s) on  
it, or does it have some structure?  Is there some way to give a  
Radiance material description to IESve directly?  When is your deadline?

-Greg

> From: "Jacob Birck Laustsen" <jbl at byg.dtu.dk>
> Date: January 5, 2007 6:43:04 AM PST
> I’m a relatively new user of Radiance and using it from within  
> IESve (the IES virtual environment program suite), which means  
> there are certain limitation for the input to the program. I’m  
> currently working on a research project on glass lamellas for  
> daylight directing and solar shading purposes at the technical  
> university of Denmark.
>
> Here’s the question:
> What is the best way to model the glass blinds in Radiance?
> The glass that I’ll be using for the project has the following  
> characteristics:
>
> Visual properties
> Ext. Reflectance, LR [%]        31
> Int. Reflectance, LR [%]        31
> Transmittance, LT [%]   59
> RA-index        97.3
>
> Solar properties
> Solar reflectance [%]   32
> Direct solar transmittance [%]  40
> Solar Absorption [%]    20/8
> g-vl/solar factor       0.48
>
> I have been trying to use the material types “trans” and  
> “dielectrica”, in order to benefit from the angular dependent  
> properties of the glass, I would prefer to use a matrial type which  
> includes the refraction index.
>
> Here comes my dilemma:
> The material type “glass”: in IESve the type does not include the  
> refraction index which means that the only input is the  
> transmissivity of the glass.
>
> The “trans” material type: same problem but at least I’m able to  
> define the reflectance of the glazing.
> The “dielectrica” material type: IESve only allows me to enter  
> values between 1 and 2 for the refraction index which in this case  
> have no significant effect.
>
> I’m sure that the best thing I could do is to model the whole thing  
> over again in the “original” Radiance – but as I have a short  
> deadline, I prefer to get it done in IESve!
>
> Hope someone out there is able to help me out on this one!
>
> Kind Regards
>
> Jacob B Laustsen, DTU, Denmark
>