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18 Nov 2024 20:37:46 EST (-0500)
  variable density (Message 1 to 8 of 8)  
From: Urs Holzer
Subject: variable density
Date: 26 Mar 2004 12:33:52
Message: <4064697a@news.povray.org>
I played with scattering media and variable density. All spheres have a
density pattern with its standard parameters and its standard color_map. I
adjusted only the scaling. It's quite interresting what you can do with
media.


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From: Dan P
Subject: Re: variable density
Date: 27 Mar 2004 13:29:03
Message: <4065c7ef@news.povray.org>
"Urs Holzer" <win### [at] hpksorg> wrote in message
news:4064697a@news.povray.org...
I played with scattering media and variable density. All spheres have a
density pattern with its standard parameters and its standard color_map. I
adjusted only the scaling. It's quite interresting what you can do with
media.


Neat! It looks like the transmit value might be a bit high -- what happens
if you set transmit to 0?

-- 
- Respectfully,
Dan
http://<broken link>


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From: Urs Holzer
Subject: Re: variable density
Date: 28 Mar 2004 02:09:20
Message: <40667a20@news.povray.org>
Dan P wrote:

> Neat! It looks like the transmit value might be a bit high -- what happens
> if you set transmit to 0?

I don't understand you. Changing the transmit value of the pigment of the
spheres wouldn't make any sense because you would only see white balls.
This is the only transmit in this scene. All other transmit values should
be 0.


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From: Dan P
Subject: Re: variable density
Date: 28 Mar 2004 12:41:47
Message: <40670e5b$1@news.povray.org>
Urs Holzer wrote:

> Dan P wrote:
> 
> 
>>Neat! It looks like the transmit value might be a bit high -- what happens
>>if you set transmit to 0?
> 
> 
> I don't understand you. Changing the transmit value of the pigment of the
> spheres wouldn't make any sense because you would only see white balls.
> This is the only transmit in this scene. All other transmit values should
> be 0.

I need to see the code to understand what you mean. The marbles looked 
like you had a transmit value to them because of the unnatural look 
inside. But, I could be totally off my rocker on this (making this just 
another one of the billions of things I'm off my rocker on) so without 
the code, I'm just making wild guesses. :-)

-- 
Respectfully,
Dan P
http://<broken link>


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From: Urs Holzer
Subject: Re: variable density
Date: 29 Mar 2004 09:53:40
Message: <40683874@news.povray.org>
Dan P wrote:
 
> I need to see the code to understand what you mean. The marbles looked
> like you had a transmit value to them because of the unnatural look
> inside. But, I could be totally off my rocker on this (making this just
> another one of the billions of things I'm off my rocker on) so without
> the code, I'm just making wild guesses. :-)

A ball looks like this:

sphere {
  0, 0.5
  pigment { rgbt 1 }
  finish { phong 0.8 }
  hollow
  interior {
    ior 1.5
    media {
      scattering { 1, rgb 1 extinction 1 }
      density {
        crackle
        scale 0.1
      }
    }
  }
}


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From: Dan P
Subject: Re: variable density
Date: 29 Mar 2004 22:36:50
Message: <4068eb52@news.povray.org>
Urs Holzer wrote:
> Dan P wrote:
>  
> 
>>I need to see the code to understand what you mean. The marbles looked
>>like you had a transmit value to them because of the unnatural look
>>inside. But, I could be totally off my rocker on this (making this just
>>another one of the billions of things I'm off my rocker on) so without
>>the code, I'm just making wild guesses. :-)
> 
> 
> A ball looks like this:
> 
> sphere {
>   0, 0.5
>   pigment { rgbt 1 }
>   finish { phong 0.8 }
>   hollow
>   interior {
>     ior 1.5
>     media {
>       scattering { 1, rgb 1 extinction 1 }
>       density {
>         crackle
>         scale 0.1
>       }
>     }
>   }
> }

I played around with it a bit and came up with this scene for fun:

#include "colors.inc"


// radiosity (global illumination) settings
global_settings {
   radiosity {
     pretrace_start 0.08           // start pretrace at this size
     pretrace_end   0.04           // end pretrace at this size
     count 35                      // higher -> higher quality (1..1600) 
[35]
     nearest_count 5               // higher -> higher quality (1..10) [5]
     error_bound 1.8               // higher -> smoother, less accurate 
[1.8]
     recursion_limit 3             // how much interreflections are 
calculated (1..5+) [3]
     low_error_factor .5           // reduce error_bound during last 
pretrace step
     gray_threshold 0.0            // increase for weakening colors 
(0..1) [0]
     minimum_reuse 0.015           // reuse of old radiosity samples [0.015]
     brightness 1                  // brightness of radiosity effects 
(0..1) [1]

     adc_bailout 0.01/2
     //normal on                   // take surface normals into account 
[off]
     //media on                    // take media into account [off]
     //save_file "file_name"       // save radiosity data
     //load_file "file_name"       // load saved radiosity data
     //always_sample off           // turn sampling in final trace off [on]
     //max_sample 1.0              // maximum brightness of samples
   }
}




camera
{
	location <0, 0.7, -2>
	look_at <0, 0, 0>
	
	up y
	right image_width / image_height * x
}




background
{
	rgb 0
}




sphere
{
	0, 0.5
	hollow

	pigment { rgbft <1, 1, 1, 1, 0> }

	finish
	{
		//phong 0.8
		specular 0.8 // New syntax is "specular"
		reflection 0.1
		
		conserve_energy // Often helps, but does not affect this image.
	}

	interior
	{
		ior 1.5
		
		media
		{
			absorption 0.1
			
			scattering
			{
				1, rgb 1
				extinction 1
			}
			
			density
			{
				crackle
				scale 0.1
				
				color_map
				{
					[0 rgb 0 ]
					[1 rgb <0.4, 0.6, 0.9>*-1*10 ]
				}
			}
		}
	}
}




plane
{
	y, -0.5
	
	pigment
	{
		checker rgb 0 rgb 2
		
		scale <0.3, 0.3, 0.3>
		rotate 30*y		
	}
	
	finish
	{
		ambient 1
		reflection 0.6
		specular 1
	}
}



sphere
{
	0, 6
	hollow
	
	pigment
	{
		color rgbft <1, 1, 1, 1, 0>
	}
	
	finish
	{
		ambient 0
		reflection 0
		specular 0	
	}
	
	interior
	{
		media
		{
			emission rgb 1
			absorption 1
			
			scattering
			{
				3, 1			
			}
			
			density
			{
				wrinkles
				scale <1, 0.1, 1>
			}
		}
	}
}

-- 
Respectfully,
Dan P
http://<broken link>


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From: Urs Holzer
Subject: Re: variable density
Date: 30 Mar 2004 04:24:00
Message: <40693cb0@news.povray.org>
Dan P wrote:

> 
> I played around with it a bit and came up with this scene for fun:
> 

Fantastic! You use nice tricks in this scene. I will remember them ...


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From: Dan P
Subject: Re: variable density
Date: 30 Mar 2004 20:25:44
Message: <406a1e18$1@news.povray.org>
Urs Holzer wrote:

> Dan P wrote:
> 
> 
>>I played around with it a bit and came up with this scene for fun:
>
> Fantastic! You use nice tricks in this scene. I will remember them ...

Thanks :-)

-- 
Respectfully,
Dan P
http://<broken link>


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