[Radiance-general] Questions about uniform sky

[Ignacio Munárriz]

1. Christopher, the theoretical factor between radiance and irradiance at a
point in that case is pi, you only have to integrate a uniform radiance over
a hemisphere to obtain it. Radiance can give some lite error due to the
randomless of indirect calculation.

2. yes,  the simulation is over hemisphere or you can determine the source
angle you want.ie

void glow sky_glow
0
0
4 1 1 1 0

sky_glow source sky
0
0
4 0 0 1 angle


----- Original Message -----
From: "Christopher Kings-Lynne" <chriskl at familyhealth.com.au>
To: "Radiance-General" <radiance-general at radiance-online.org>
Sent: Friday, February 25, 2005 11:05 AM
Subject: [Radiance-general] Questions about uniform sky


> Hi,
>
> I'm just trying to understand a few things about using a uniform sky.
>
> 1. With a uniform sky, how can I determine the theoretical irradiance or
> illuminance at 0,0,0 looking straight up?  I'm currently testing a
> polygon on the z=0 plane and I get a slight variance in the illumination
> across that surface, due to slight errors in the calcs I presume.  What
> I need is the theoretical exact value...
>
> 2. With a uniform sky, will the position of my test plane matter?  ie.
> If I translate the plane from the origin +10000 in the Z direction, will
> the illumination on that plane still be identical?
>
> Thanks,
>
> Chris
>
> _______________________________________________
> Radiance-general mailing list
> Radiance-general at radiance-online.org
> http://www.radiance-online.org/mailman/listinfo/radiance-general
>