POV-Ray : Newsgroups : povray.general : Superellipsoids & Orthographic Camera - Bug ? Server Time
9 Aug 2024 17:18:17 EDT (-0400)
  Superellipsoids & Orthographic Camera - Bug ? (Message 1 to 5 of 5)  
From: Peter Houston
Subject: Superellipsoids & Orthographic Camera - Bug ?
Date: 16 May 2000 05:55:44
Message: <39211b20@news.povray.org>
I believe there is a bug in the POV-Ray code, it is evident when you view a
superellipsoid with an orthographic camera and rotate it y*90 ( refer to
image in p.b.i and code in p.t.s-f)

I have noticed that it happens in Official 3.1g (Windows), MegaPov 0.4 and
MegaPOV 0.5

Regards,

Peter H.

--
____________________________________________________________________
 ___ _  _                                                  _______
| _ \ || | Peter Houston   Houston Graphics 3D Sketch Pad |__ /   \
|  _/ __ |       http://welcome.to/HoustonGraphics         |_ \ |) |
|_| |_||_| ICQ#  8770407     Latest Update : 11 May 2000  |___/___/


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From: Chris Huff
Subject: Re: Superellipsoids & Orthographic Camera - Bug ?
Date: 16 May 2000 22:25:58
Message: <chrishuff_99-794914.21292816052000@news.povray.org>
In article <39211b20@news.povray.org>, "Peter Houston" 
<hou### [at] inamecom> wrote:

> I believe there is a bug in the POV-Ray code, it is evident when you 
> view a superellipsoid with an orthographic camera and rotate it y*90 
> ( refer to image in p.b.i and code in p.t.s-f)
> 
> I have noticed that it happens in Official 3.1g (Windows), MegaPov 
> 0.4 and MegaPOV 0.5

This might be the problem:
camera {...
    location  <0.0, 0, -10>
    ...
    look_at   <0.0, 0.0,  0.0>
    ...
}

I seem to remember there being precision problems with cameras pointed 
along an axis...I could be wrong though. Anyway, try moving the camera 
slightly.

-- 
Christopher James Huff - Personal e-mail: chr### [at] yahoocom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Personal Web page: http://chrishuff.dhs.org/
TAG Web page: http://tag.povray.org/


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From: Ken
Subject: Re: Superellipsoids & Orthographic Camera - Bug ?
Date: 16 May 2000 22:59:26
Message: <39220A7A.96047D74@pacbell.net>
Chris Huff wrote:

> This might be the problem:
> camera {...
>     location  <0.0, 0, -10>
>     ...
>     look_at   <0.0, 0.0,  0.0>
>     ...
> }
> 
> I seem to remember there being precision problems with cameras pointed
> along an axis...I could be wrong though. Anyway, try moving the camera
> slightly.

There are no problems with the example above. This will usualy cause
Pov to freak out though -

camera {
        location <0,0,0>
        look_at <0,-1,0>
       }

-- 
Ken Tyler - 1400+ POV-Ray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/


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From: Peter Houston
Subject: Re: Superellipsoids & Orthographic Camera - Bug ?
Date: 17 May 2000 06:46:05
Message: <3922786d@news.povray.org>
I changed location to < 0 , 0.000000001 , -10 > and it worked fine.

Should it still be reported as a bug, as it only happens with a rotation
about y ?

Regards,


Peter H.

> This might be the problem:
> camera {...
>     location  <0.0, 0, -10>
>     ...
>     look_at   <0.0, 0.0,  0.0>
>     ...
> }
>
> I seem to remember there being precision problems with cameras pointed
> along an axis...I could be wrong though. Anyway, try moving the camera
> slightly.


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From: Peter Popov
Subject: Re: Superellipsoids & Orthographic Camera - Bug ?
Date: 17 May 2000 10:55:59
Message: <khc5is4eiq159lfthh178j9kq3dhithck9@4ax.com>
On Tue, 16 May 2000 21:29:28 -0500, Chris Huff
<chr### [at] yahoocom> wrote:

>I seem to remember there being precision problems with cameras pointed 
>along an axis...I could be wrong though. Anyway, try moving the camera 
>slightly.

This only holds true if the direction vector is parallel to the y
axis. However I am pretty certain that what we're seeing here is a
precision problem related to the bounding scheme and the fact that it
only manifests itself with the orthographic camera.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] usanet
TAG      e-mail : pet### [at] tagpovrayorg


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