POV-Ray : Newsgroups : povray.binaries.images : Highlight bug in Object Collection metals : Re: Highlight bug in Object Collection metals Server Time
11 Aug 2022 18:55:37 EDT (-0400)
  Re: Highlight bug in Object Collection metals  
From: Cousin Ricky
Date: 18 Jan 2022 16:31:18
Message: <61e731a6@news.povray.org>
On 2022-01-17 19:52 (-4), Cousin Ricky wrote:
> 
>   It seems logical that if two spheres present the same color, the
> macro setting the highlight should give both spheres the same highlight.
> 
> ... and I need to fix that.

Last night, while I was trying to get to sleep with a streetlight
shining through my window (long story), a solution came to me.  There is
still a slight difference that I can't explain.  My guess is that even
with a totally black pigment, there is some Fresnel effect, which
POV-Ray applies, while as far as my proposed solution is concerned,
diffuse 0 + reflection 0 = specular 0.  I doubt the difference will be
significant in practice, but I may take a look at the Fresnel formula
anyway.

These are the textures used on the two black spheres:

----------[LEFT SPHERE (BLACK PIGMENT)]----------
  pigment
  { color <0.0000, 0.0000, 0.0000, 0.0000, 0.0000>
    quick_color <0.0000, 0.0000, 0.0000>
  }
  finish
  { reflection { 0.0000 metallic }
    diffuse 1.0000
    ambient rgb <0.0000, 0.0000, 0.0000>
    emission 0
    brilliance 1.6667
    specular albedo 0.2500 metallic
    roughness 0.02500
  }
----------[RIGHT SPHERE (ZERO DIFFUSE)]----------
  pigment
  { color <0.9900, 0.7600, 0.3300, 0.0000, 0.0000>
    quick_color <0.9900, 0.7600, 0.3300>
  }
  finish
  { reflection { 0.0000 metallic }
    diffuse 0.0000
    ambient rgb <0.0000, 0.0000, 0.0000>
    emission 0
    brilliance 1.6667
    specular albedo 0.000 metallic
    roughness 0.02500
  }
----------[END CODE]----------

P.S. About using zero reflection and a high diffuse in a metallic
texture, I did mention that I was cheating, right?


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