Warp <war### [at] tagpovrayorg> wrote:
> CAS <sup### [at] cstnetcn> wrote:
> > I have known the value of solar irradiance in 817nm band is 1.08279
> > W/(m2*nm).How can I define it?  "light_source {<sun_x,sun_y,sun_z> color rgb
> > 1.08279 } "I set statement as above in pov,but I doublt it is wrong,because
> > 1.08279 is a solar irradiance,color rgb is color ，but I donnot know how
> > to convert them or how to define solar irradiance.beg a hot to help me !thank
> > you!
>
> Note that for the most part POV-Ray uses a quite simplistic Phong
> lighting model with RGB values. It does not model light at different
> wavelengths, nor is it able to process colors in any more complicated
> ways than manipulating RGB values, nor are most of its lighting
> calculations any more complex than the simple Phong lighting model.
>
> (Note that "Phong lighting model", or "Phong reflection model", should
> not be confused with "phong highlights". The lighting model is an
> illumination model that simply adds three components to the color of
> a surface: ambient (a constant), diffuse (a lighting component that's
> independent of the viewing angle) and specular (a lighting component
> that's dependent on the viewing angle).)
>
> Far from me to disparage POV-Ray, but to be completely honest, the
> Phong lighting model is quite poor and simplistic. (It's *major*
> advantage is that it's very fast and can produce, when properly used,
> acceptable results.)
>
> If you want to convert a unit of irradiance into RGB, you'll have to
> figure out the conversion formula. This is probably not a trivial task,
> nor is it probably very productive because of the limitations of the
> lighting model described above.
>
> (There are many problems in getting an "accurate" conversion from some
> standard irradiance unit to RGB. One of them is that the relation between
> irradiance and the apparent brightness of what ends up on your monitor
> screen is subject to rather complex gamma curve functions, which are not
> only dependent on the gamma used by POV-Ray and the image file, but also
> the gamma correction performed by your display hardware and the screen.)
>
> --
>                                                           - Warp
I have tryed to modify my code "light_source {<sun_x,sun_y,sun_z>
            color rgb <1.00229e-005,3.46021e-006,-5.65828e-007>*10}"or *100,I
find the result is the same as the "light_source {<sun_x,sun_y,sun_z>
            color rgb <1.00229e-005,3.46021e-006,-5.65828e-007>".
what I know is the value of reflection of each sphere .this reflection is amount
to specular (a lighting component that's dependent on the viewing
angle)."pigment {color rgb spectral}"maybe this sentence is wrong,this sentence
I defined in order to describe the spectral of each sphere.Maybe I should use
"finish {spectral X}".
I know pov is a render ,if I define light_source ,camera,objects,it will get a
image,I am not quite clear how pov to calculate  color of each pixel,only use
photon model?

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