POV-Ray : Newsgroups : povray.news-submissions : Spectral Rendering with POV-Ray V0.2 available : Re: Spectral Rendering with POV-Ray V0.2 available Server Time
6 Jun 2023 23:01:21 EDT (-0400)
  Re: Spectral Rendering with POV-Ray V0.2 available  
From: CAS
Date: 2 Apr 2014 04:05:01
Message: <web.533bc3af894b4d246a92a3a00@news.povray.org>
Ive <ive### [at] lilysoftorg> wrote:
> Am 02.12.2013 23:56, schrieb clipka:
> > How are you addressing the problem of synthesizing spectra from RGB values?
> >
> I did use the blue, green, red patch of row 3 from the color checker
> chart - assuming that the color experts at Gretag have had reasons to
> choose these -  together with a "luminance" multiplier to make sure
> equal values do produce something like gray.
> Someone more serious than me would have used one of the CIE color match
> functions, after all these represent what an average human calls pure
> red, green and blue.
> > One thought: Shouldn't it be possible to support image maps by wrapping
> > them in a pigment function? It'll still be synthesized from RGB, but
> > better than no support at all (or so I think).
> >
> Hm, I did not think of that, but now that you mention it, this should
> certainly be possible. Maybe something for version 0.3.
> > Oh, and one more thing: I understand that you have the necessary
> > equipment to measure materials' spectra. Would you mind providing a few
> > selected plastic materials like, say... LEGO bricks? (both opaque and
> > transparent, please) ;-)
> >
> Funny that you think of LEGO bricks. I had exactly the same idea of
> using them as "reference colors" when I discussed lightsys with Jaime
> about 10 years ago. But meanwhile I do not have a single brick anymore.
> But I did measure them and might still have the data on some old hard
> disk within some Pentium 3 machine, me thinks ;)
> I will look for it, but I'm really not sure, so any other ideas...
> -Ive

Hey,my name is miaoyu, I am a student,I have read your article about "spectral
rendering with pov-ray".And I also have visited  your website
http://lilysoft.org. How beautiful your works are! But I want to beg a help from
you. I am studying pov to do my graduation project.I have confronted some
confusions,please give me a help,expecting your replying!Greate gratitudes!
My questions:
1: The value of solar irradiance in 817nm is 1.08279W/(m2*nm).How can I set
related statements in pov?
2:How can I make the value of each pixel of final image be radiance? not color.

My codes are as bolow:
#version 3.7;
global_settings{ assumed_gamma 1.0 }  #include "spectral.inc" #declare
SpectralWavelength = 817nm;
angle  7.54371
location <camera_x,camera_y,camera_z >
look_at <0,0,0>
rotate <0,-31,0>
right x
up y
light_source {<sun_x,sun_y,sun_z>
            color rgb  1.08279 }

#declare geom_file_name = "pov-xyz.txt";
#declare spec_file_name = "pov-ref.txt";
#declare n=o;
#fopen   Input_geom_file geom_file_name read
#fopen   Input_spec_file spec_file_name read
#while(defined(Input_geom_file Input_spec_file))
        <x1-center_x,y1-center_y,z1-center_z>, //sphere location
         1.55     //sphere radius
        finish {specular ref}  //sphere BRDF
    #declare n = n + 1;

Can you help me to check it,Beg a help! Greate gratitudes!

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