Hi Mehlika,

The genskyvec program is designed to work with gendaylit and gensky input, 
only.  That isn't to say you shouldn't be able to generate an equivalent output 
from an HDR capture of the sky dome, but genskyvec isn't going to be much help 
with that.  You are looking at a manual process until and unless someone gets 
around to automating it.

Here are some of the necessary steps:

1) Create a Radiance description of a scene using your captured sky as a 
colorpict input with the appropriate fisheye mapping.
2) Extract the $rhcal variable from genskyvec.pl, which defines the Reinhart 
sky sampling needed.
3) Assign the MF constant to the desired Reinhart subdivision resolution 
(default 4 in genskyvec).
4) Call cnt with the number of sky patches as given by the Rmax constant 
defined in $rhcal and the number of samples per patch (16 in genskyvec but you 
may need more if you're trying to resolve the sun).
5) Pipe the output of cnt into rcalc and rtrace as done in the $tregcommand 
variable in genskyvec.pl.
6) The output of rtrace goes into total to sum patch values together, and this 
basically produces your desired vector, minus the ground plane.
7) Insert a ground plane triple at the beginning based on the expected ground 
brightness (irradiance times reflectance over pi) and you're done.

-Greg

> From: Mehlika Inanici <[email protected]>
> Date: February 23, 2013 1:57:48 PM PST
> 
> Hi everyone,
> 
> Is there a way to run genskyvec with an HDR sky image? If yes, how? I could 
> not come up with the right solution. 
> 
> Thanks,
> Mehlika
> 

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