# One (or more) window behind another

Hi,
ï¿½
I am calculating Average Daylight Factors by sampling the illuminance on a grid within the room.
ï¿½
I frequently come across situations where there are two completely separate layers of glazing serving a room.ï¿½ One example is for a room looking into anï¿½atrium with a glazed roof.ï¿½There is one layer of glazing in the window in the room, and a second in the roof.ï¿½ I am not sure how best to treat this.ï¿½ï¿½ï¿½Normally I would use mkillum on the room glazing, and allow daylight to penetrate through the atrium roof.ï¿½ Does anyone know if there is possibly a 2 stage procedure so that the atrium roof is treated as a secondary source as well as the room window?
ï¿½
Another example, this time with 3 layers of separate glazing, is whereï¿½there is a corridor between theï¿½room in the above example and the glazed atrium, and the corridor has windows looking into the atrium.
ï¿½
ï¿½
I would be glad of anyone's thoughts on this.
ï¿½
Malcolm
ï¿½
ï¿½ï¿½

Malcolm Macpherson (Director)

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Hi Malcolm,

In general, you can arrange your input surfaces for mkillum any way you think will benefit your calculation. You don't have to worry about what happens when one window sees another, but if you want to know what happens in such cases, check out section 13.1.3 in "Rendering with Radiance" starting on page 572.

If you still have questions, maybe you could be a little more specific about your concerns.
-Greg

From: "Malcolm Macpherson" <[email protected]>
Date: January 21, 2005 9:12:39 AM PST

Hi,

I am calculating Average Daylight Factors by sampling the illuminance on a grid within the room.

I frequently come across situations where there are two completely separate layers of glazing serving a room. One example is for a room looking into an atrium with a glazed roof. There is one layer of glazing in the window in the room, and a second in the roof. I am not sure how best to treat this. Normally I would use mkillum on the room glazing, and allow daylight to penetrate through the atrium roof. Does anyone know if there is possibly a 2 stage procedure so that the atrium roof is treated as a secondary source as well as the room window?

Another example, this time with 3 layers of separate glazing, is where there is a corridor between the room in the above example and the glazed atrium, and the corridor has windows looking into the atrium.

I would be glad of anyone's thoughts on this.

Malcolm