mkillum settings - borrowed light

radiance-general
1

I have a simple two room project with substantial sunshades on the outer
windows. The second room is only lit via 'borrowed' light at the top of
the wall between the two rooms.

My question is: "How to use mkillum with different parameters for the
two sets of windows using rad?"

For the outside windows, genrad suggests a ground ambient level of 68.5
thus I would need to specify an -av 68.5 68.5 68.5, -ab 1 and possibly
s=16 d=8.

For the internal windows, which can be seen through (to the ceiling of
the other room) I am not sure as to the av settings. Tests using the av
68.5 settings, while giving a good gradient, have an odd bright band on
the ceiling, so I assume the av would need to be lower - how to
determine that value or do you simply leave it out.

As I am using trad/rad I want to embed the commands within the window
rad file rather than in the rif 'mkillum=' line. Reading the man page
for mkillum, it suggests that these options can be embedded but have had
no success to date.

Any suggestions would be appreciated.

Regards

Terrance Mc Minn

2

Hi!

For the outside windows, genrad suggests a ground ambient level of 68.5

hm, genrad, not part of the radiance distribution? Is it genrad from that old CAD-integration project?

As I am using trad/rad I want to embed the commands within the window
rad file rather than in the rif 'mkillum=' line. Reading the man page
for mkillum, it suggests that these options can be embedded but have had
no success to date.

Just add a line at the beginning of the window's scene description:

#@mkillum s=16 d=8

As for specifying different av settings for the windows, I guess things will get really complicated when you want to automate the mkillum processes. You can specify the mkillum settings in the input file, but what you want to set (av, ar, ...) are the rtrace parameters that mkillums uses when starting rtrace processes.

Do you really need different av's? I'd increase the overall ambient accuracy, set a high ab (not needed for the outer windows, but it is not so important in rendering times if only used for the illum generation).

Good luck! Lars.

3

Hello Lars,

Thanks for the tips.

Hmmm....

The genrad program is from the work of Simon Crone: "The genrad program has
been written to supply calculated direct and diffuse radiation to either of
the two RADIANCE sky distribution programs (gensky and gendaylit), where no
measured data is available."

It supposedly produces more realistic skies especially for Perth (Western
Australia)

Regards

Terry Mc Minn