POV-Ray : Newsgroups : povray.general : disk bug? Server Time
6 Nov 2024 02:21:48 EST (-0500)
  disk bug? (Message 1 to 4 of 4)  
From: Tom Melly
Subject: disk bug?
Date: 14 Nov 2002 11:47:24
Message: <3dd3d39c@news.povray.org>
In the following scene, I get the "camera inside non-hollow object" warning - is
this a (previously unreported) bug?

I get the warning even when (as in the scene below) the camera is positioned
outside the radius of the disk. In other words the disk behaves like a plane.

Ideally, I suppose one might expect never to get this warning with a disk,
unless the camera was inside the radius of the disk and at the same height as
the disk, but I imagine that this is not possible. At anyrate, even if not a
bug, it might be worth a comment in the docs...

#version 3.5;

#include "colors.inc"

global_settings {
  assumed_gamma 1.0
}

camera {
  location  <0.0, 0, -20.0>
  look_at   <0.0, 0,  0.0>
}

light_source {
  0*x
  color rgb <1,1,1>
  translate <40, 80,0>
}

disc{<0,2,0>,z,1 pigment{White}}

--
#macro A(V,B,C,R)#while(B-256)#if(V-128/B>=0)sphere{0,.5translate<C-4R-1,9>
pigment{rgb<1-C/8R/2C/8>}}#local V=V-128/B;#end#local B=B*2;#local C=C+1;#
end#end A(234,1,0,2)A(85,1,0,1)A(81,1,0,0)light_source{-5 1}//Tom Melly


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From: hughes, b 
Subject: Re: disk bug?
Date: 14 Nov 2002 11:56:09
Message: <3dd3d5a9@news.povray.org>
"Tom Melly" <tom### [at] tomandlucouk> wrote in message
news:3dd3d39c@news.povray.org...
> In the following scene, I get the "camera inside non-hollow object"
warning - is
> this a (previously unreported) bug?
>
> I get the warning even when (as in the scene below) the camera is
positioned
> outside the radius of the disk. In other words the disk behaves like a
plane.
>
> Ideally, I suppose one might expect never to get this warning with a disk,
> unless the camera was inside the radius of the disk and at the same height
as
> the disk, but I imagine that this is not possible. At anyrate, even if not
a
> bug, it might be worth a comment in the docs...

I thought disc was described in the Doc as being like a plane.

Ah ha! Yes it is, just checked. Says:

Note: The inside of a disc is the inside of the plane that contains the
disc. Also note that it is not constrained by the radius of the disc.


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From: Tom Melly
Subject: Re: disk bug?
Date: 14 Nov 2002 12:14:25
Message: <3dd3d9f1@news.povray.org>
"hughes, b." <omn### [at] charternet> wrote in message
news:3dd3d5a9@news.povray.org...
>
> Ah ha! Yes it is, just checked. Says:
>
> Note: The inside of a disc is the inside of the plane that contains the
> disc. Also note that it is not constrained by the radius of the disc.
>

Oops - somehow (presumably because it's boxed) that was the only bit of the
entry on disks that I failed to read. Doh...


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From: Le Forgeron
Subject: Re: disk bug?
Date: 19 Nov 2002 06:41:33
Message: <3DDA236D.1030804@free.fr>
hughes, b. wrote:

> I thought disc was described in the Doc as being like a plane.
> 
> Ah ha! Yes it is, just checked. Says:
> 
> Note: The inside of a disc is the inside of the plane that contains the
> disc. Also note that it is not constrained by the radius of the disc.
> 


Now, I have a question: Why is it so ?
Moreover, excepted for 'Camera insideness', is the 'Inside' test of a 
disc ever used for something ? (media ? CSG intersection/difference 
seems out of range...)
Was it for some 'interior texture vs exterior texture' ?


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