fls13 wrote:
> Ah, and how do you do that? :O) 

   Ouch! ...I thought the demos will show that, but obviously I 
commented them poorly.

> alone if I understood how. I set up a page with some figure meshes hacked
> into the demos and the camera moved about.
> http://www.geocities.com/fls13ec/PovTest-Lightsys4.html

   These look very nice... you seem to have fit the scale very well.

> For example, what do the .inc files actually include? I see in
> lightsys_constants.inc file certain brands of light bulbs are assigned a
> certain amount of lumens. Then there is a relationship with a spline that
> is defined in either espd_cie_standard.inc or espd_lightsys.inc. At least I
> think. 

   The contents of the include files are explained on the readme files, 
and it's too long to explain here, but about the constants, there are 
basically 3 types: typical lumens intensity values, typical color 
temperatures on kelvin degrees, and usual light colors in rgb format 
converted from spectral data (the splines contain the spectral data for 
the light bulbs, which are converted to rgb colors with the help of the 
CIE macros). You need usually these 3 types of data as parameters for 
the Lightsys and CIE macros.

> How do you insert in a scene a GE 100 watt lightbulb in a particular
> location, like a lamp? 

   Use the Light() macro supplying the desired parameters:

   object{
    Light(
     EmissiveSpectrum(ES_GE_SW_Incandescent_100w), // direct conversion
     Lm_Incandescent_100w, // from lightsys_constants.inc
     0,0,0,0,0 // no area_light nor cosine falloff spotlight
    )
   }

   or if you prefer to use the light_source directly (to tweak other 
features), there are some "sub-macros" which can be used to have the 
same result:

   light_source{
     <0,0,0>
     Light_Color(
      EmissiveSpectrum(ES_GE_SW_Incandescent_100w),
      Lm_Incandescent_100w
     )
     Light_Fading()
   }

> Or how about sunlight streaming through a window
> into a room?

   Just replace the spectrum with a sunlight one. Or use the Daylight() 
macro for a calculation based on the kelvin temperature: see the 
demo_outdoor scene... I know the demos are not very well commented, but 
I think it should not be too hard to simply grasp the basic usage of the 
main macros to use them on your own scenes. Or so I hope... perhaps I 
should write some more examples, if I find someday my didactic vein.

--
Jaime

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