[Radiance-general] Difference between .pic colours and traced ray colours

[Greg Ward]

Hi Tarik,

I couldn't really follow your question:

> I'm wondering why when I view a .pic image I've created in HDRShop, 
> the pixel
> values aren't the same as when I generate a text file of their colours 
> using
> vwrays.

I first read this as if you had created the .pic in HDRShop, which 
didn't make sense.  I assume now you are only viewing it with HDRShop.  
What do you mean that the pixel values aren't the same?  The same as 
what?  The same as eachother?  You are expecting them all to be the 
same?  ??

> I wnat a green box's surface reflectances in the pic file so I do
>
> ./vwrays.exe -fd greenbox.pic | rtrace -fda `vwrays -d greenbox.pic`
> -ovm `if(s='green_plastic')` testroom.oct  | grep "green_plastic" > 
> rays.txt

Ignoring the `if(s='green_plastic')` nonsense, which I'm hoping doesn't 
do anything, this command might give you the luminance at each visible 
point on the green surface, but not its reflectance.  If you want the 
reflectance, just look at the Radiance scene file.  It's right there in 
the definition of "green_plastic".

-Greg