[Radiance-general] mkillum illuminating outside?

[Lars O. Grobe]

Hi,

I just got some surprising results from mkillum.

I have a very basic set-up, that consists of a test-room facing a wall 
with a small window. I put a koffer around the open side of the room, 
and define these surfaces as illums using mkillum. In the next step, I 
display only the scene illuminated by the mkillum-generated illum - the 
sky dome that was used to generate the illum has been removed here, to 
have only the contribution by the illum visible.

Now the illum replaces the indirekt contribution into the room, and this 
looks ok. But - the illum also illuminates the outside geometry in my 
case. So I have a bright area on the wall opposite of my test room. This 
is also clearly visible from inside (the sky dome has been switched on 
again in that case).

I never came to think about it, but this would mean that in all those 
cases, where we place an illum inside a fenestration, the fenestrations 
inner surfaces will appear brigther then they should be, right?

CU Lars.


Images are available at:

http://www.larsgrobe.de/mkillum_inside.jpg
http://www.larsgrobe.de/mkillum_outside.jpg

the yellow wireframe is supposed to explain the illum surfaces...