POV-Ray : Newsgroups : povray.pov4.discussion.general : Aspect Ratio Handling Server Time
14 Jul 2024 06:55:38 EDT (-0400)
  Aspect Ratio Handling (Message 1 to 8 of 8)  
From: Greg Kennedy
Subject: Aspect Ratio Handling
Date: 24 Jul 2023 00:50:00
Message: <web.64be0248be2530f65f52366d3f6a0c2d@news.povray.org>
The default POV-Ray camera setting for "right" is a 4:3 ratio, designed to match
the default 4:3 output (for 4:3 screens) leading to a 1:1 pixel aspect ratio.

A common stumbling block for new users is attempting to render a 16:9 image,
which leads to non-square pixels and the output appearing horizontally
stretched.  This means a search in the manual until you discover the magic words
"right x*ImageWidth/ImageHeight" to produce the desired aspect ratio.

The rationale for 4:3 default in the manual FAQ section is pretty thin these
days, as people are not rendering Windows XP startup screens any more, and it
seems FAR more likely that users will want a 1:1 PAR by default (which they can
change if needed for special cases).

I suggest for 4.0, that the default for camera Right be automatically set to the
same ratio as the requested image output ratio, which means 16:9 resolutions
will work "out of the box", and that users wanting an anamorphic ratio should
instead tweak Right themselves (overriding the default).


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From: jr
Subject: Re: Aspect Ratio Handling
Date: 24 Jul 2023 04:10:00
Message: <web.64be310c33bc165780c03e9d6cde94f1@news.povray.org>
hi,

"Greg Kennedy" <ken### [at] gmailcom> wrote:
> The default POV-Ray camera setting for "right" is a 4:3 ratio, designed to match
> the default 4:3 output (for 4:3 screens) leading to a 1:1 pixel aspect ratio.
>
> A common stumbling block for new users is attempting to render a 16:9 image,
> which leads to non-square pixels and the output appearing horizontally
> stretched.  This means a search in the manual until you discover the magic words
> "right x*ImageWidth/ImageHeight" to produce the desired aspect ratio.
>
> The rationale for 4:3 default in the manual FAQ section is pretty thin these
> days, as people are not rendering Windows XP startup screens any more, and it
> seems FAR more likely that users will want a 1:1 PAR by default (which they can
> change if needed for special cases).
>
> I suggest for 4.0, that the default for camera Right be automatically set to the
> same ratio as the requested image output ratio, which means 16:9 resolutions
> will work "out of the box", and that users wanting an anamorphic ratio should
> instead tweak Right themselves (overriding the default).

you already can, and are "encouraged to do", adjust the global 'povray.ini' file
after installation; simply add the desired 'Width's and 'Height's ?

also, fwiw and afaik, I've not had any "non-square pixels and the output
appearing horizontally stretched" problems.  (rendering 16:9 and 16:10 regularly
on a machine with a 5:4 monitor)


regards, jr.


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From: Bald Eagle
Subject: Re: Aspect Ratio Handling
Date: 24 Jul 2023 07:25:00
Message: <web.64be5f4a33bc16571f9dae3025979125@news.povray.org>
"Greg Kennedy" <ken### [at] gmailcom> wrote:
> The default POV-Ray camera setting for "right" is a 4:3 ratio, designed to match
> the default 4:3 output (for 4:3 screens) leading to a 1:1 pixel aspect ratio.
>
> A common stumbling block for new users is attempting to render a 16:9 image,
> which leads to non-square pixels and the output appearing horizontally
> stretched.  This means a search in the manual until you discover the magic words
> "right x*ImageWidth/ImageHeight" to produce the desired aspect ratio.
>
> The rationale for 4:3 default in the manual FAQ section is pretty thin these
> days, as people are not rendering Windows XP startup screens any more, and it
> seems FAR more likely that users will want a 1:1 PAR by default (which they can
> change if needed for special cases).
>
> I suggest for 4.0, that the default for camera Right be automatically set to the
> same ratio as the requested image output ratio, which means 16:9 resolutions
> will work "out of the box", and that users wanting an anamorphic ratio should
> instead tweak Right themselves (overriding the default).

I, and others completely understand these little things that drive new users
crazy - since we were all once new users, and sometimes get caught making newbie
mistakes even now.

The Insert menu is there to solve many of these problems, along with example
scenes, and scenes posted my users to the forum.   There kind of is a FAQ that
covers stuff like this - maybe it should be made more prominent, and maybe a
VERY simple new user guide should be written walking someone through the various
necessary and sufficient steps to writing a basic scene.

The paradox of all of this is that the more you hand them, the less they learn,
and the more disconnected they get from the HOWs and WHYs of everything - which
just winds up kicking the stumbling block further down the road.

The Shadertoy community has some amazing content, and they write ALL of the code
for ALL of the elements of their scenes from scratch.   Camera, lighting, the
functions for all of the shapes and colors - everything.

So, I would say that there ought to be a two-prong approach, one addressing the
quick and easy copy-paste to speed the creation of a working scene, but with the
proviso and caveat that the user should work through a more technical version of
the scene to gain an understanding of WHAT they are doing with the various
commands, arguments, and values, and WHY.

Mindlessly plopping text into a .pov file without understanding any of it is a
sure recipe for greater eventual frustration, when they want to start really
making nice looking scenes, and still don't for the life of them know HOW.


That's the just way of things, I guess..

- BW


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From: Thomas de Groot
Subject: Re: Aspect Ratio Handling
Date: 24 Jul 2023 10:25:18
Message: <64be89ce$1@news.povray.org>
Op 24-7-2023 om 13:23 schreef Bald Eagle:
> "Greg Kennedy" <ken### [at] gmailcom> wrote:
>> The default POV-Ray camera setting for "right" is a 4:3 ratio, designed to match
>> the default 4:3 output (for 4:3 screens) leading to a 1:1 pixel aspect ratio.
>>
>> A common stumbling block for new users is attempting to render a 16:9 image,
>> which leads to non-square pixels and the output appearing horizontally
>> stretched.  This means a search in the manual until you discover the magic words
>> "right x*ImageWidth/ImageHeight" to produce the desired aspect ratio.
>>
>> The rationale for 4:3 default in the manual FAQ section is pretty thin these
>> days, as people are not rendering Windows XP startup screens any more, and it
>> seems FAR more likely that users will want a 1:1 PAR by default (which they can
>> change if needed for special cases).
>>
>> I suggest for 4.0, that the default for camera Right be automatically set to the
>> same ratio as the requested image output ratio, which means 16:9 resolutions
>> will work "out of the box", and that users wanting an anamorphic ratio should
>> instead tweak Right themselves (overriding the default).
> 
> I, and others completely understand these little things that drive new users
> crazy - since we were all once new users, and sometimes get caught making newbie
> mistakes even now.
> 
> The Insert menu is there to solve many of these problems, along with example
> scenes, and scenes posted my users to the forum.   There kind of is a FAQ that
> covers stuff like this - maybe it should be made more prominent, and maybe a
> VERY simple new user guide should be written walking someone through the various
> necessary and sufficient steps to writing a basic scene.
> 
> The paradox of all of this is that the more you hand them, the less they learn,
> and the more disconnected they get from the HOWs and WHYs of everything - which
> just winds up kicking the stumbling block further down the road.
> 
> The Shadertoy community has some amazing content, and they write ALL of the code
> for ALL of the elements of their scenes from scratch.   Camera, lighting, the
> functions for all of the shapes and colors - everything.
> 
> So, I would say that there ought to be a two-prong approach, one addressing the
> quick and easy copy-paste to speed the creation of a working scene, but with the
> proviso and caveat that the user should work through a more technical version of
> the scene to gain an understanding of WHAT they are doing with the various
> commands, arguments, and values, and WHY.
> 
> Mindlessly plopping text into a .pov file without understanding any of it is a
> sure recipe for greater eventual frustration, when they want to start really
> making nice looking scenes, and still don't for the life of them know HOW.
> 
> 
> That's the just way of things, I guess..
> 
> - BW
> 

A page that can help (new) users is:

https://wiki.povray.org/content/Reference:Keywords

The advantage is that it is the latest up-to-date version, including 
changes related to version 3.8.

For the present topic, the default for right is:

right <image_width/image_height,0,0>

-- 
Thomas


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From: Cousin Ricky
Subject: Re: Aspect Ratio Handling
Date: 24 Jul 2023 12:55:00
Message: <web.64beabb033bc165760e0cc3d949c357d@news.povray.org>
"Greg Kennedy" <ken### [at] gmailcom> wrote:
>
> I suggest for 4.0, that the default for camera Right be automatically set to the
> same ratio as the requested image output ratio, which means 16:9 resolutions
> will work "out of the box", and that users wanting an anamorphic ratio should
> instead tweak Right themselves (overriding the default).

This is already done in POV-Ray 3.8, so long as the scene file starts with

  #version 3.8;


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From: Alain Martel
Subject: Re: Aspect Ratio Handling
Date: 24 Jul 2023 13:05:38
Message: <64beaf62$1@news.povray.org>
Le 2023-07-24 à 00:47, Greg Kennedy a écrit :
> The default POV-Ray camera setting for "right" is a 4:3 ratio, designed to match
> the default 4:3 output (for 4:3 screens) leading to a 1:1 pixel aspect ratio.
> 
> A common stumbling block for new users is attempting to render a 16:9 image,
> which leads to non-square pixels and the output appearing horizontally
> stretched.  This means a search in the manual until you discover the magic words
> "right x*ImageWidth/ImageHeight" to produce the desired aspect ratio.
> 
> The rationale for 4:3 default in the manual FAQ section is pretty thin these
> days, as people are not rendering Windows XP startup screens any more, and it
> seems FAR more likely that users will want a 1:1 PAR by default (which they can
> change if needed for special cases).
> 
> I suggest for 4.0, that the default for camera Right be automatically set to the
> same ratio as the requested image output ratio, which means 16:9 resolutions
> will work "out of the box", and that users wanting an anamorphic ratio should
> instead tweak Right themselves (overriding the default).
> 
As of version 3.8, the default right vector is now :
x*image_width/image_height

That mean that there is no more stretching/squishing.
So, your request is already fulfilled.


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From: Alain Martel
Subject: Re: Aspect Ratio Handling
Date: 24 Jul 2023 13:07:41
Message: <64beafdd$1@news.povray.org>
Le 2023-07-24 à 12:49, Cousin Ricky a écrit :
> "Greg Kennedy" <ken### [at] gmailcom> wrote:
>>
>> I suggest for 4.0, that the default for camera Right be automatically set to the
>> same ratio as the requested image output ratio, which means 16:9 resolutions
>> will work "out of the box", and that users wanting an anamorphic ratio should
>> instead tweak Right themselves (overriding the default).
> 
> This is already done in POV-Ray 3.8, so long as the scene file starts with
> 
>    #version 3.8;
> 
> 
Or
	#version version;

The above will automatically set the used version to the actual version 
of the program.


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From: Greg Kennedy
Subject: Re: Aspect Ratio Handling
Date: 3 Aug 2023 16:25:00
Message: <web.64cc0c4133bc16575f3255453f6a0c2d@news.povray.org>
Alain Martel <kua### [at] videotronca> wrote:

> > The default POV-Ray camera setting for "right" is a 4:3 ratio, designed to match
> > the default 4:3 output (for 4:3 screens) leading to a 1:1 pixel aspect ratio.
> >
> > A common stumbling block for new users is attempting to render a 16:9 image,
> > which leads to non-square pixels and the output appearing horizontally
> > stretched.  This means a search in the manual until you discover the magic words
> > "right x*ImageWidth/ImageHeight" to produce the desired aspect ratio.
> >
> > The rationale for 4:3 default in the manual FAQ section is pretty thin these
> > days, as people are not rendering Windows XP startup screens any more, and it
> > seems FAR more likely that users will want a 1:1 PAR by default (which they can
> > change if needed for special cases).
> >
> > I suggest for 4.0, that the default for camera Right be automatically set to the
> > same ratio as the requested image output ratio, which means 16:9 resolutions
> > will work "out of the box", and that users wanting an anamorphic ratio should
> > instead tweak Right themselves (overriding the default).
> >
> As of version 3.8, the default right vector is now :
> x*image_width/image_height
>
> That mean that there is no more stretching/squishing.
> So, your request is already fulfilled.

Oh that's great!  I didn't realize it was already changed (still using 3.7) and
assumed that my next chance to get a feature request in would be 4.0.  Thanks
for the clarification :)


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