> As long as only YOU render a scene, then, it's ok.
> If you create your scene and you plan to have it rendered at various 
> aspect ratio, then it's also workable. You made it so that it's complete 
> even if parts are not visible, and it's modeled outside the visible area.

Sure.

> If you create a scene using a specific aspect ratio and publish it, then 
> it's not ok anymore.

The problem is though the alternative is also not ok (but in a different 
way).  In extreme cases it's obvious, but if someone renders a 1280x1024 
desktop wallpaper at 1600x1200 it might not be obvious things are a little 
distorted.  Currently as scene-author you need to decide which behaviour you 
prefer when your scene gets rendered at a different aspect ratio (even if 
you're rendering it yourself, eg for different monitors).

As has been discussed many times here before, it would be nice for the scene 
author to have a little more control over the aspect ratio the scene gets 
rendered at, and for the person starting the render to choose what to do in 
case of a mismatch.

BTW the point in the FAQ about the "angle" keyword is clutching at straws, 
if you're already using the image_width and image_height variables, then 
just use them in the angle statement as well if you want to control the FOV 
differently.

Post a reply to this message

Am 08.12.2010 09:40, schrieb scott:

>> If you create a scene using a specific aspect ratio and publish it,
>> then it's not ok anymore.
>
> The problem is though the alternative is also not ok (but in a different
> way). In extreme cases it's obvious, but if someone renders a 1280x1024
> desktop wallpaper at 1600x1200 it might not be obvious things are a
> little distorted. Currently as scene-author you need to decide which
> behaviour you prefer when your scene gets rendered at a different aspect
> ratio (even if you're rendering it yourself, eg for different monitors).

This topic has been discussed over and over and over again - so rather 
than discuss what is the best approach to solve the issue with the tools 
available, I propose to fast-forward the discussion to the point where 
POV-Ray's current toolbox for handling aspect ratio issues is found to 
be incomplete.

See http://bugs.povray.org/task/85 for information on feature proposals 
to mitigate this issue.

For the time being, my personal recommendation for people like me who 
don't want to bother much about aspect ratio is to use the famous 
image_width/image_height approach, irregardless of what that 
equally-famous but somewhat outdated FAQ recommends - because chances 
are they won't be rendering to non-square-pixel targets, nor be too 
outraged if someone happened to render their scene at a "wrong" aspect 
ratio.

For all those who want their scenes to be "aspect-ratio safe", I'd 
suggest to use a simple workaround like:

#define AspectRatio = 4/3;
camera {
   up    y/AspectRatio
   right x
   #if (image_width/image_height <> AspectRatio)
     #warning "Unexpected aspect ratio.\n"
     #error "Comment out this line if you know what you are doing.\n"
   #end
}

And finally, for people who want to be constructive about this issue, 
I'd suggest picking up the glove to write a macro library to help 
dealing with aspect ratio.

Post a reply to this message

Am 07.12.2010 15:20, schrieb Le_Forgeron:
> Le 07/12/2010 14:37, daedalouse a écrit :
>> But it did not work out. I render with Width=1280 Height=1024.
>
> If you are rendering the scene at the root of the thread, it cannot work
> with +W1280 +H1024
>
> 1280 / 1024 is a 5:4 ratio.
> Default (3.6) ratio is 4:3;
> No Cigare!

Actually, 3.6 (and also 3.7, as of beta 40) defaults to an aspect ratio 
of 1.330 : 1, which is almost but not quite 4:3...

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well...yes, my fault :-)

1280 / 1024 = 5/4  != 4/3 ^^


right x*image_width/image_height


did the trick.

Thanks, a lot

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