POV-Ray : Newsgroups : povray.newusers : "ultra_wide_angle" use perspective? Server Time: 22 Nov 2019 04:23:13 GMT
  "ultra_wide_angle" use perspective? (Message 1 to 3 of 3)  
From: fuyok
Subject: "ultra_wide_angle" use perspective?
Date: 25 Oct 2019 07:00:00
Message: <web.5db29c35e36875162dc3df130@news.povray.org>
Hello.

I'm a Japanese student. I use POV-Ray for my research.

I would like to hear about the projection method of "ultra_wide_angle" camera.
CG drawn with an ultra-wide-angle camera shows a distortion of the curve that
cannot be seen with perspective, but the actual wide-angle camera is due to
perspective projection, so there is almost no distortion. In POV-Ray, I would
like to know how the super wide angle is expressed and what projection method is
used.


In addition, I would like to know if there is a way to manipulate “distortion”
in POV-Ray. (A real lens has a theory that formalizes distortion called
"distortion aberration")

I'm sorry in my very poor English.


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From: Alain Martel
Subject: Re: "ultra_wide_angle" use perspective?
Date: 25 Oct 2019 15:16:54
Message: <5db311e6$1@news.povray.org>
Le 2019-10-25 à 02:54, fuyok a écrit :
> Hello.
> 
> I'm a Japanese student. I use POV-Ray for my research.
> 
> I would like to hear about the projection method of "ultra_wide_angle" camera.
> CG drawn with an ultra-wide-angle camera shows a distortion of the curve that
> cannot be seen with perspective, but the actual wide-angle camera is due to
> perspective projection, so there is almost no distortion. In POV-Ray, I would
> like to know how the super wide angle is expressed and what projection method is
> used.

This is explained in the documentation, section 3.4.2.2 «Types of 
projection».
It start here :
https://www.povray.org/documentation/3.7.0/r3_4.html#r3_4_2_2

> 
> 
> In addition, I would like to know if there is a way to manipulate “distortion”
> in POV-Ray. (A real lens has a theory that formalizes distortion called
> "distortion aberration")
> 
> I'm sorry in my very poor English.
> 
> 

You can make a lens and place it just in front of the camera.
#declare Lens=intersection{
   sphere{0 1} // at the origin, radius of 1 unit
   box{<1,1,1><-1,-1,0.1>} // remove the rear part
   pigment{rgbt 1} // perfectly transparent
   translate -0.88*z // 0.02 unit in front of the default camera
   interior{ior 1.5 dispersion 1.01 dispersion_sample 12}
   // make it optically active
}

This will create a basic plano-convex lens that show some chromatic 
aberration.
It is located and oriented correctly for the default camera orientation 
and location.
You can scale is to better suit your need. You can scale unevenly.
You can change the dispersion to make the dispersion more or less obvious.

You should have some basic to start experimenting.


Alain


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From: fuyok
Subject: Re: "ultra_wide_angle" use perspective?
Date: 5 Nov 2019 04:55:00
Message: <web.5dc100696ee857672dc3df130@news.povray.org>
Thank you for the hint.


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