[Radiance-general] FW: Gensky Question

[Nick Devlin]

Hi All, 

I have a GENSKY question that I cant find the answer to in the archives. I
suspect that the answer is straightforward, but I am now challenging all my
old assumptions as I have just switched from old school desktop radiance to
3R7P2 with photon mapping running under Ubuntu on VMware Workstation.
Daunting, but I like it!

Perhaps first I should state that I am aware from the listings that perhaps
I should be using Gendaylit rather than Gensky, but I have not managed to
compile it yet. Compiling makes me anxious. I used Francesco's Linux
binaries in the end as I couldn't get photon map to compile properly after
3R7P2. My /bin and /lib files are not in the standard location, but I have
altered PATH & RAYPATH accordingly. 

So, to the questions:

Firstly, I have some data for sky brightness from BRE Availability of
Daylight, for diffuse and direct illuminance. If for example, I have
illuminance values of 34 klux diffuse and 26 klux direct can I explicitly
set these in Gensky (assuming 179lux per watt) with 

Gensky (location details, azimuth etc) +s -B 189 -R 145.25 > skyfile.rad

My concern is whether -B or -R overrides the other, or will I ultimately
result in approximately total 60klux horizontal illuminance? 

Secondly, do I have to manually add the following to the bottom of
skyfile.rad. I presume that I don't need to alter any of the parameters here
for a basic sky and ground plane and that it references the skyfunc output
from the gensky command. 

skyfunc glow skyglow
0
0
4
	.85 1.04 1.2  0

skyglow source sky
0
0
4
	0 0 1  180

skyfunc glow groundglow
0
0
4
	.8 1.1 .8  0

groundglow source ground
0
0
4
	0 0 -1  180

Finally, if I explicitly set -B & -R for an intermediate sky with +i does
the +i setting result in an adjustment to the -B & -R values? 

Many thanks in advance

Nick Devlin.