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22 Dec 2024 11:04:19 EST (-0500)
  using camera (Message 1 to 5 of 5)  
From: CRIS
Subject: using camera
Date: 31 Jul 2012 04:55:01
Message: <web.50179c9f86e2ae6da2ae615c0@news.povray.org>
Hi, i would like to know if, with pov ray, and in particulary with the use of

sees in reality and how it sees; this in order to check for occlusion with other
objects in the scene.
thanks
Cris


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From: Stephen
Subject: Re: using camera
Date: 31 Jul 2012 13:55:53
Message: <50181c29$1@news.povray.org>
On 31/07/2012 9:51 AM, CRIS wrote:
> Hi, i would like to know if, with pov ray, and in particulary with the use of
> the object 'camera' i'm able to simulate and know which object  a real camera
> sees in reality and how it sees; this in order to check for occlusion with other
> objects in the scene.
> thanks
> Cris
>
>
Hi Cris,
	I am not too sure what you mean. I think that the best way to see what 

picking up your meaning.
On the other hand, if you use a PovRay modeller then you get an OpenGL 
view from the camera. As well as plan and elevation views.


-- 
Regards
     Stephen


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From: CRIS
Subject: Re: using camera
Date: 1 Aug 2012 04:20:01
Message: <web.5018e5d6e553e0e2a2ae615c0@news.povray.org>
Stephen <mcavoys_at@aoldotcom> wrote:
> On 31/07/2012 9:51 AM, CRIS wrote:
> > Hi, i would like to know if, with pov ray, and in particulary with the use of
> > the object 'camera' i'm able to simulate and know which object  a real camera
> > sees in reality and how it sees; this in order to check for occlusion with other
> > objects in the scene.
> > thanks
> > Cris
> >
> >
> Hi Cris,
>  I am not too sure what you mean. I think that the best way to see what

> picking up your meaning.
> On the other hand, if you use a PovRay modeller then you get an OpenGL
> view from the camera. As well as plan and elevation views.
>
>
> --
> Regards
>      Stephen

In fact I have not explained very well;  in practice I want to know if povray
faithfully reproduces the view of a real camera, but i think the answer is 'yes'
because this is the main functionality of povray.
thanks


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From: Le Forgeron
Subject: Re: using camera
Date: 1 Aug 2012 04:32:43
Message: <5018e9ab$1@news.povray.org>
Le 01/08/2012 10:16, CRIS a écrit :
> Stephen <mcavoys_at@aoldotcom> wrote:
>> On 31/07/2012 9:51 AM, CRIS wrote:
>>> Hi, i would like to know if, with pov ray, and in particulary with the use of
>>> the object 'camera' i'm able to simulate and know which object  a real camera
>>> sees in reality and how it sees; this in order to check for occlusion with other
>>> objects in the scene.
>>> thanks
>>> Cris
>>>
>>>
>> Hi Cris,
>>  I am not too sure what you mean. I think that the best way to see what
>> the camera sees is to render the scene. So I don’t think that I am
>> picking up your meaning.
>> On the other hand, if you use a PovRay modeller then you get an OpenGL
>> view from the camera. As well as plan and elevation views.
>>
>>
>> --
>> Regards
>>      Stephen
> 
> In fact I have not explained very well;  in practice I want to know if povray
> faithfully reproduces the view of a real camera, but i think the answer is 'yes'
> because this is the main functionality of povray.
> thanks
> 
> 

It depends on the kind of camera you use and the kind of camera you
specify for povray.

See:
> http://wiki.povray.org/content/Reference:Camera#Types_of_Projection

For instance, you might want to specify the actual angle of a
perspective camera. (not all real camera have the same angle, a zoom
might change it too!)


-- 
Those who would give up Essential Liberty to purchase <
a little Temporary Safety, deserve neither Liberty nor Safety.

Benjamin Franklin


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From: clipka
Subject: Re: using camera
Date: 1 Aug 2012 10:54:43
Message: <50194333@news.povray.org>
Am 01.08.2012 10:16, schrieb CRIS:

> In fact I have not explained very well;  in practice I want to know if povray
> faithfully reproduces the view of a real camera, but i think the answer is 'yes'
> because this is the main functionality of povray.

Actually, it's much more complicated than that.

What it /does/ faithfully reproduce is a pinhole camera (using the 
"perspective" camera), or a single-lens camera; but those distort 
objects seen at wide angles in an undesired fashion, so modern lens 
systems introduce additional "shaping" of the image countering this 
effect. OTOH this "shaping" has the unintended but inevitable side 
effect of bending straight lines, so camera manufacturers always need to 
make a trade-off there, and might make different choices for individual 
lens models.

So faithfully reproducing "a" real camera would require knowledge about 
that particular camera's exact properties, and a way to inform POV-Ray 
about it. POV-Ray doesn't go as far as that - it just offers /one/ 
individual choice of such trade-off (using the "ultra_wide_angle" camera).


That said, if you are only interested in the question of which objects 
are occluded by other objects, there is no difference between individual 
camera lens systems: As long as you ignore focal blur, they're all 
equivalent to using a classic pinhole camera and then applying some 
distortion filter to the resulting 2D image.


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