POV-Ray : Newsgroups : povray.general : Widescreen Camera Trick? Server Time
2 Aug 2024 14:14:24 EDT (-0400)
  Widescreen Camera Trick? (Message 11 to 13 of 13)  
<<< Previous 10 Messages Goto Initial 10 Messages
From: Tom Galvin
Subject: Re: Widescreen Camera Trick?
Date: 11 Nov 2004 05:40:28
Message: <4193419c$1@news.povray.org>
Tim Nikias wrote:
> It would also take care that the
> resulting image would always be easily reproducable exactly without the need
> to measure pixels...
> 
> 

Or to avoid measuring pixels

3.1.2.2.2  Partial Output Options
....
Start_Row=0.n  Set first row to n percent of height
+SR0.n or +S0.n  Same as Start_Row=0.n

End_Row=0.n  Set last row to n percent of height
+ER0.n or +E0.n  Same as End_Row=0.n


Post a reply to this message

From: stm31415
Subject: Re: Widescreen Camera Trick?
Date: 11 Nov 2004 09:00:01
Message: <web.41936fc1cd7bbd6eb95333480@news.povray.org>
"Tim Nikias" <JUSTTHELOWERCASE:timISNOTnikias(at)gmx.netWARE> wrote:
> but if the area where the rays are
> shot were concave instead of flat, and every point's normal would point
> towards the camera, I think that the horizontal lines should stay
> horizontal, and the vertical lines vertical, with no distortion whatsoever.

A concave surface will result in curved horizontals. The distortion would be
minimal as far as perspective goes, but the only way it would lok vorrect
would be if the display survace were equally curved.

When thinking about this, I like to imagine that you are looking THROUGH the
final image. if the final image is based on a curved survace, the only way
to see the undistorted image again would be through a curved image.
Transparent graph paper helps, too.

What I *think* you want is the two-point perspective control I was asking
about earlier. 3D is *about* distortion... without it, the images would not
look real at all. The idea is to create a point at wich the viewer can look
at the image and the distortion of the image is the _same_ as the
distortion of the real world on thier eye, thus looking like a window into
another world, rather than just a distorted picture.

Look into two-point perspective. If you figure out how to control it in
POV-Ray, you can just put the second point further away. This will reduce
distortion. The only issue with the technique is that it also reduces depth
(i.e. the squares of a checkered plane will start more squished on the
depth axis).

Hope this helps (some),

-S
5TF!


Post a reply to this message

From: Tim Nikias
Subject: Re: Widescreen Camera Trick?
Date: 11 Nov 2004 10:44:12
Message: <419388cc@news.povray.org>
> What I *think* you want is the two-point perspective control I was asking
> about earlier.

Thanks, I'll look up on it and try to find out if its what I need. But,
knowing myself, I'll probably resort to using neither the macro linked to in
a different reply, nor the two-point perspective control, but instead use
some weirdo combination of angles, aspect-ratios and camera type to get
something that I find visually pleasing... :-)

Regards,
Tim

-- 
"Tim Nikias v2.0"
Homepage: <http://www.nolights.de>


Post a reply to this message

<<< Previous 10 Messages Goto Initial 10 Messages

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.