[Radiance-general] mkillum-generated distribution files

[Lars O. Grobe]

Hi,

I am trying to understand the output of mkillum. The dat-files are 
written in Radiance's standard format. So I should be able to understand 
the header. However I am not really sure whether I am doing the right 
thing here. Take an example:
--
2
1.041667 0.041667 13
0.000000 6.283185 39

  1.504918e+00 1.530097e+00 1.525389e+00 1.501599e+00 1.505246e+00
  1.461270e+00 1.463038e+00 1.489136e+00 1.481565e+00 1.451201e+00
  1.374334e+00 1.296027e+00 1.410817e+00 1.343876e+00 1.477319e+00
  1.365996e+00 1.366200e+00 1.397315e+00 1.407394e+00 1.484092e+00
  1.482776e+00 1.570183e+00 1.525340e+00 1.572320e+00 1.561935e+00
  1.576046e+00 1.486079e+00 1.629394e+00 1.528797e+00 1.621227e+00
[...]
--
My understanding:

1) I have a two-dimensional array (line 1) of 13 rows and 39 columns 
(lines 2, 3), right?

2) The rows are counted down from 1 to 0 (the 0.041667 probably is some 
error to avoid 0), thus in steps of 1/13=-0.0769 .

3) The columns are counted up from 0 to 2*pi in steps of 6.2832/39=0.1611 .

4) This means that the columns represent the "azimuth angle" (the angle 
in the plane of the illum surface) from 0 to 2*pi radians, the rows are 
related to.... what? If it were the elevation angle (the angle to the 
surface normal of the mkillum surface), why is it not counted beyond 1 
radians? Or what else is it?

In illum.cal which is referred to by the illum-modifier generated by 
mkillum, I find these comments:
--
For the hemispherical case, A1-A9 are the unit vectors for the
hemisphere's coordinate system:

il_alth         - Altitude (1 to 0) for hemispherical coordinates
il_azih         - Azimuth (0 to 2*PI) for hemisphere
--
It would be great if anyone could shed some light onto this...

Cheers, Lars.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 3740 bytes
Desc: S/MIME Cryptographic Signature
Url : http://radiance-online.org/pipermail/radiance-general/attachments/20100720/03c46c95/smime.bin