Modelling of glass blinds in Radiance.

Hi Everyone

I�m a relatively new user of Radiance and a frequent reader of the archieves from the mailing list - great ideas and advices! I’m running a modified version of Radiance 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 is Antelio Silver from SGG with the following characteristics:

Antelio Silver

Visual properties

Ext. Reflectance, LR [%]


Int. Reflectance, LR [%]


Transmittance, LT [%]




Solar properties

Solar reflectance [%]


Direct solar transmittance [%]


Solar Absorption [%]


g-vl/solar factor


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 matrialtype which includes the refraction index.

Here comes my dilemma:

The material type �glass�, but 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 to finish the project by middle of February, time is running out and I think I would break my neck just getting started! (But I will definitely try to get started after finishing this project!)

Hope someone out there is able to help me out on this one!

Kind Regards

Tine Skotte, DTU, Denmark


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