POV-Ray : Newsgroups : povray.general : Glass texture and interior problem Server Time
31 Jul 2024 18:17:31 EDT (-0400)
  Glass texture and interior problem (Message 1 to 6 of 6)  
From: dave vanhorn
Subject: Glass texture and interior problem
Date: 18 Dec 2006 22:14:30
Message: <45875916$1@news.povray.org>
Well, things are going better, but I have a problem with my glass texture.
I posted the scene file in scene-files, and the image in images.

What's happening is that the red is exactly what I want, but the blue, which 
is the same texture, is barely visible.. Not sure what I need to do to fix 
this.

The two objects are using exactly the same texture.

The relevant bits below, compressed


#declare Col_Sapphire_06 = color rgbf  <0.0784, 0.1706, 1.0000, 0.99>;
#declare Col_Ruby_06     = color rgbf  <1.0000, 0.1706, 0.0784, 0.99>;


#declare Glass_Interior = interior { ior 2.5
                                     caustics 1.0
                                   }

#declare Glass = texture { pigment { rgbf <0.98, 1.0, 0.99, 0.99> }
                           finish { ambient 0.0 //0.10 // As if from 
scattered light in the scene
                                    diffuse 0.0 //0.10 // reflections from 
light sources
                                    brilliance 0.0 // higher makes more 
metallic appearance
                                    #ifndef (Phong_Off)
                                      phong 1.0
                                      phong_size 50 // higher = more 
polished
                                      metallic 0.5 // 0 - 1
                                    #end

                                    reflection { .01 // mirror-like quality 
, min max
                                                 fresnel on
                                                 metallic 0 // 0-> 1
                                               }

                                    specular 0.25 //Similar to phong, all 
over the surface
                                                   // too much spec looks 
like pool balls
                                    roughness .02 //This gives a nice shine, 
0.00005 - 1.0 (rough)
                                    conserve_energy
                                  }
                         }

// Ruby glass
#declare Ruby_Glass = texture { Glass
                                pigment { Col_Ruby_06 }
                              }

// Saphire glass
#declare Saph_Glass = texture { Glass
                                pigment { Col_Sapphire_06 }
                              }

#declare M_Ruby_Glass = material { texture {Ruby_Glass}
                                   interior {Glass_Interior}
                                 }

#declare M_Saph_Glass = material { texture {Saph_Glass}
                                   interior {Glass_Interior}
                                 }


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From: Grassblade
Subject: Re: Glass texture and interior problem
Date: 19 Dec 2006 16:10:01
Message: <web.458853d7fde9e5dae6efd0310@news.povray.org>
That's a pretty cool picture.
The black background conspires with the dark blue to make the red much more
apparent. Pick a lighter background colour like a neutral gray, or go all
the way to white.
Colour-wise, <0.0784, 0.1706, 1.0000> is somewhat different from <1.0000,
0.1706, 0.0784>, I mean, apart from the obvious hue change. In The Gimp the
red <255,40,20> looks significantly brigther to me than the blue <20,40,255>
(I obtained these values by multiplying your colour vector by 256). It could
be just monitor settings, though. :p


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From: dave vanhorn
Subject: Re: Glass texture and interior problem
Date: 19 Dec 2006 18:43:50
Message: <45887936@news.povray.org>
"Grassblade" <nomail@nomail> wrote in message 
news:web.458853d7fde9e5dae6efd0310@news.povray.org...
> That's a pretty cool picture.
> The black background conspires with the dark blue to make the red much 
> more
> apparent. Pick a lighter background colour like a neutral gray, or go all
> the way to white.

I tried white as background, and as sky sphere, looked like hell.
Also, both background and sky sphere seemed to illuminate the scene pretty 
powerfully. I had my single light set to 0.00 and ambient set globally to 0.

> Colour-wise, <0.0784, 0.1706, 1.0000> is somewhat different from <1.0000,
> 0.1706, 0.0784>, I mean, apart from the obvious hue change. In The Gimp 
> the
> red <255,40,20> looks significantly brigther to me than the blue 
> <20,40,255>
> (I obtained these values by multiplying your colour vector by 256). It 
> could
> be just monitor settings, though. :p

Yeah, it looks ok on my monitor, but not nearly as bright as the red.
I will post another version that uses just the hearts, and the exact same 
material in blue looks fabulous.
 Must be the lighting angles?


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From: St 
Subject: Re: Glass texture and interior problem
Date: 20 Dec 2006 03:47:14
Message: <4588f892@news.povray.org>
"dave vanhorn" <mic### [at] gmailcom> wrote in message 
news:45887936@news.povray.org...

> Yeah, it looks ok on my monitor, but not nearly as bright as the red.
> I will post another version that uses just the hearts, and the exact same 
> material in blue looks fabulous.
> Must be the lighting angles?

    Dave, I tried your original code with black background and turned rad 
and photons off. The blue to me, looked better.

    ~Steve~


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From: "Jérôme M. Berger"
Subject: Re: Glass texture and interior problem
Date: 20 Dec 2006 07:03:12
Message: <45892680$1@news.povray.org>
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Hash: SHA1

Grassblade wrote:
> That's a pretty cool picture.
> The black background conspires with the dark blue to make the red much more
> apparent. Pick a lighter background colour like a neutral gray, or go all
> the way to white.
> Colour-wise, <0.0784, 0.1706, 1.0000> is somewhat different from <1.0000,
> 0.1706, 0.0784>, I mean, apart from the obvious hue change. In The Gimp the
> red <255,40,20> looks significantly brigther to me than the blue <20,40,255>
> (I obtained these values by multiplying your colour vector by 256). It could
> be just monitor settings, though. :p
> 
	It's not just your monitor settings: perceptually, the same value
is significantly darker if it's blue than red (and green is the
brightest). When computing the equivalent brightness for a colour,
you should use the following coefficients:

In the Gimp on a PC (Macs have different values):
brightness = blue * 0.11 + green * 0.54 + red * 0.35

In Povray the coefficients should be gamma corrected:
brightness = blue * 0.02 + green * 0.71 + red * 0.27

		Jerome
- --
+------------------------- Jerome M. BERGER ---------------------+
|    mailto:jeb### [at] freefr      | ICQ:    238062172            |
|    http://jeberger.free.fr/     | Jabber: jeb### [at] jabberfr   |
+---------------------------------+------------------------------+
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From: dave vanhorn
Subject: Re: Glass texture and interior problem
Date: 20 Dec 2006 23:13:37
Message: <458a09f1$1@news.povray.org>
I know about the perceptual difference, but the same material really lights 
up at a different angle. But, that won't work with the scene.


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