POV-Ray : Newsgroups : povray.newusers : camera usage (correct aspect ratio) Server Time
30 Jul 2024 16:16:19 EDT (-0400)
  camera usage (correct aspect ratio) (Message 1 to 4 of 4)  
From: Matthew Pace
Subject: camera usage (correct aspect ratio)
Date: 27 Oct 2003 19:14:14
Message: <matt-pace-71382B.16141427102003@netplex.aussie.org>
Hello, I have been away for awhile, although you may not remember 
because I was not here long to be gin with.  Anyways, I am back for now, 
with another question:  How can I set up the camera so that no matter 
what custom size I use for the picture (whether it be 1024x768 or 
468x48), the image does not get distorted.  I tried using the "right" 
keyword mixed with variations of image_height/image_width and such, but 
my image always came out stretched, not entirely on screen, backwards, 
or with the camera looking in from the back side of the scene.  I am 
sure there is a way to set it up so that every image comes out 
correctly, I just need help finding it.  I could not locate it at any 
tutorial site.  Thanks a lot, Matthew


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From: Hughes, B 
Subject: Re: camera usage (correct aspect ratio)
Date: 27 Oct 2003 20:23:20
Message: <3f9dc508@news.povray.org>
"Matthew Pace" <mat### [at] lycoscom> wrote in message
news:mat### [at] netplexaussieorg...
> Hello, I have been away for awhile, although you may not remember
> because I was not here long to be gin with.  Anyways, I am back for now,

I remember you.

> with another question:  How can I set up the camera so that no matter
> what custom size I use for the picture (whether it be 1024x768 or
> 468x48), the image does not get distorted.  I tried using the "right"
> keyword mixed with variations of image_height/image_width and such, but
> my image always came out stretched, not entirely on screen, backwards,

right image_width/image_height*x

This way you get the aspect ratio needed. You just had it opposite based on
what you stated above. Maybe you missed this variation?

If that wasn't the reason you found to do this correctly the other thing
that matters here is the image output resolution needs to match at least the
aspect ratio. So... if image_height=480 and image_width=640, dividing them
makes 1.333333 for the aspect ratio, then you could conceivably use any
other such resolution for the image output size as long as keeping the same
ratio. Anyway, it's height divided by width for 'right'.
-- 
Bob H.
http://www.3digitaleyes.com


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From: Matthew Pace
Subject: Re: camera usage (correct aspect ratio)
Date: 27 Oct 2003 20:37:43
Message: <matt-pace-F76DE9.17374227102003@netplex.aussie.org>
> right image_width/image_height*x
> 
> This way you get the aspect ratio needed. You just had it opposite based on
> what you stated above. Maybe you missed this variation?
> 
> If that wasn't the reason you found to do this correctly the other thing
> that matters here is the image output resolution needs to match at least the
> aspect ratio. So... if image_height=480 and image_width=640, dividing them
> makes 1.333333 for the aspect ratio, then you could conceivably use any
> other such resolution for the image output size as long as keeping the same
> ratio. Anyway, it's height divided by width for 'right'.

Ok, thanks for the corrected version, I will try it out.  Can you 
clarify what the second part is?  Do you mean that if I start a scene at 
640x480, I could render the image at 800x600 and have it look the same 
(except bigger), but if i were to render it the second time at 500x250 , 
it would come out distorted?

thanks for your help,
Matt


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From: Hughes, B 
Subject: Re: camera usage (correct aspect ratio)
Date: 27 Oct 2003 22:04:32
Message: <3f9ddcc0@news.povray.org>
"Matthew Pace" <mat### [at] lycoscom> wrote in message
news:mat### [at] netplexaussieorg...
> > right image_width/image_height*x
> >
> > This way you get the aspect ratio needed. You just had it opposite based
on
> > what you stated above. Maybe you missed this variation?
> >
> > If that wasn't the reason you found to do this correctly the other thing
> > that matters here is the image output resolution needs to match at least
the
> > aspect ratio. So... if image_height=480 and image_width=640, dividing
them
> > makes 1.333333 for the aspect ratio, then you could conceivably use any
> > other such resolution for the image output size as long as keeping the
same
> > ratio. Anyway, it's height divided by width for 'right'.
>
> Ok, thanks for the corrected version, I will try it out.  Can you
> clarify what the second part is?  Do you mean that if I start a scene at
> 640x480, I could render the image at 800x600 and have it look the same
> (except bigger), but if i were to render it the second time at 500x250 ,
> it would come out distorted?

Exactly. It's all about aspect ratio of the resulting resolution when you're
using image_width divided by image_height, since those two values are
creating a new different value to multiply by x (if x is your camera's left
to right direction). Should always be okay until you use non-default values
for 'up' or other camera changes.

Glad to help.


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