[Radiance-general] Sky illumination vs. mkillum

[Christopher Kings-Lynne]

Hi all,

I'm tearing my hair out here trying to grok mkillum windows vs. sky 
illumination through the window.

I am trying to visualise the DIRECT sky factor on the floor of a room 
before and after a new building is put in.  The green area is the area 
that is above 0.2% sky factor before the building and the red area is 
the area that is above 0.2% sky factor after the new building is put in.

I have tried with and without mkillum:

Skyglow:

http://img138.exs.cx/img138/977/skyglow8bi.gif

Mkillum:

http://img239.exs.cx/img239/2804/mkillum7kx.gif

Note that the skyglow one would seem to be much more accurate (basically 
a big building that covers almost all the window in the top left edge is 
put in), but the mkillum one has smoother edges.

I guess what I just do not understand after hours of playing with all 
the rendering and mkillum settings is how to either:

* get rid of the speckling in the skyglow render

or

* make the mkillum render actually accurate (in particular, the green 
leakage in the top left corner seems wrong)

Can anyone give any suggestions?

Thanks,

Chris