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2 Jul 2024 11:21:49 EDT (-0400)
  light diffraction using photons (Message 1 to 3 of 3)  
From: Herbert Koob
Subject: light diffraction using photons
Date: 12 Nov 2010 14:30:35
Message: <op.vl2og7jg3wevk9@amilo.fritz.box>
Hello,

I want to deal with light diffraction using photons. In the PovRay manua
l  

chapter 3.6.3.1.1 there are shown
two examples. Where can I find the related source code?


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From: Alain
Subject: Re: light diffraction using photons
Date: 12 Nov 2010 20:11:55
Message: <4cdde5db$1@news.povray.org>

> Hello,
>
> I want to deal with light diffraction using photons. In the PovRay
> manual chapter 3.6.3.1.1 there are shown
> two examples. Where can I find the related source code?
>
>

POV-Ray support reflection and refraction. Refraction also support 
chromatic dispersion.

Diffraction is NOT supported as it depends on waves interference and 
there is no light waves in the model used.

You should continue your reading for the following sections: 3.6.3.2 to 
3.6.4

There is no diffraction in either of those scenes. There is also NO 
dispersion.
The first image show only a single white light_source.
The second one DON'T actualy use dispersion but fake it using 3 
light_sources, one red, one green and one blue.

To my knowlege, the POV files for those scenes are not included with the 
distribution.

The following sample files use photons and are included in the 
distribution. They can be found in the advanced folder:
diffract.pov
newdiffract.pov
optics.pov
grenadine.pov

NONE of those show any diffraction.

What is important to know:
1 - You must turn photons ON in the global_settings, and specify ether 
the total number of photons (count) to shoot OR the density of the 
photons (spacing). There are other oprional parameters.

2 - The objects that are meant to interact with the photons need a 
photons block to set them as target and enable reflection or refraction.

3 - You don't need any photons block for the light_source. ALL 
light_source without "shadowless" automaticaly shoot photons whenever 
photons are enabeled.
  - shadowless light_source NEVER shoot any protons. They also never 
cause any highlight.

4 - For ANY transparent object that have an ior and dispersion set to a 
value different than 1 AND zero, the dispersion will affect photons. 
There is nothing else to add.

Thin film interference CAN be simulated using irid in the finish.



Alain


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From: Herbert Koob
Subject: Re: light diffraction using photons
Date: 14 Nov 2010 09:48:42
Message: <op.vl50rd2h3wevk9@amilo.fritz.box>
Hello Alain,

thank you for the hints. I will study the mentioned sample files. If I  

have further questions, I will come back to here.

Herbert





Am 13.11.2010, 02:11 Uhr, schrieb Alain <aze### [at] qwertyorg>:


>> Hello,
>>
>> I want to deal with light diffraction using photons. In the PovRay
>> manual chapter 3.6.3.1.1 there are shown
>> two examples. Where can I find the related source code?
>>
>>
>
> POV-Ray support reflection and refraction. Refraction also support  

> chromatic dispersion.
>
> Diffraction is NOT supported as it depends on waves interference and  

> there is no light waves in the model used.
>
> You should continue your reading for the following sections: 3.6.3.2 t
o  

> 3.6.4
>
> There is no diffraction in either of those scenes. There is also NO  

> dispersion.
> The first image show only a single white light_source.
> The second one DON'T actualy use dispersion but fake it using 3  

> light_sources, one red, one green and one blue.
>
> To my knowlege, the POV files for those scenes are not included with t
he  

> distribution.
>
> The following sample files use photons and are included in the  

> distribution. They can be found in the advanced folder:
> diffract.pov
> newdiffract.pov
> optics.pov
> grenadine.pov
>
> NONE of those show any diffraction.
>
> What is important to know:
> 1 - You must turn photons ON in the global_settings, and specify ether
  

> the total number of photons (count) to shoot OR the density of the  

> photons (spacing). There are other oprional parameters.
>
> 2 - The objects that are meant to interact with the photons need a  

> photons block to set them as target and enable reflection or refractio
n.
>
> 3 - You don't need any photons block for the light_source. ALL  

> light_source without "shadowless" automaticaly shoot photons whenever 
 

> photons are enabeled.
>   - shadowless light_source NEVER shoot any protons. They also never  

> cause any highlight.
>
> 4 - For ANY transparent object that have an ior and dispersion set to 
a  

> value different than 1 AND zero, the dispersion will affect photons.  

> There is nothing else to add.
>
> Thin film interference CAN be simulated using irid in the finish.
>
>
>
> Alain


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