[Radiance-general] Radiance -av setting

[Greg Ward]

Hi Erik,

I think the difference is due to the fact that points closer to the  
window see more of the sky directly, whose value is unaffected by the  
-av setting.  Towards the back of the room, more rays encounter  
opaque surfaces, where -av does matter.

-Greg

> From: "Erik Moore" <Erik.Moore at arup.com>
> Date: August 30, 2008 3:53:39 AM PDT
> Dear all, I’m playing with the settings in Radiance. I’ve noted  
> something that I don’t get. Attached are two draphs of DF in a room  
> for various numbers of ambient bounces (1-4). The top chart  
> (ahigh1-4.opt) is without an ambient value turned on while the  
> bottom chart (bhigh1-4.opt) is with an ambient value of 0.28 applied.
>
> Why does the illuminance calculated invert at the back of the room 
> ( -ab 1 is  the highest) when we give an ambient value? Surly all  
> values should be altered by the same amount?
>
> I have also run the calculation for no ambient bounces and without  
> a sky description. In this case a flat graph is created (i.e. all  
> points see exactly the same illuminance). This is what I would have  
> expected to see….all points raised by a factor related to the –av  
> setting.
>
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