POV-Ray : Newsgroups : povray.beta-test : Problem with "no_image" and transparency? Server Time
24 Apr 2024 01:18:21 EDT (-0400)
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From: Ansgar
Subject: Re: Problem with "no_image" and transparency?
Date: 25 Sep 2007 04:15:00
Message: <web.46f8c270aff96f2fcb86afba0@news.povray.org>
It does not happen in 3.6.
Transparent or semi-transparent parts let the background color of the scene
show through, as it should be.


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From: Ansgar
Subject: Re: Problem with "no_image" and transparency?
Date: 25 Sep 2007 05:10:00
Message: <web.46f8d032aff96f2fcb86afba0@news.povray.org>
I just went through the POV-Ray help and found this in the section about
"no_image".

"When no_image is used, the object will not be seen by the camera, either
directly or through transparent/refractive objects. However, it will still
cast shadows, and show up in reflections (unless no_reflection and/or
no_shadow is used also)."

There you go. The object is not supposed to be seen through
transparent/refractive objects.


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From: Warp
Subject: Re: Problem with "no_image" and transparency?
Date: 25 Sep 2007 06:55:34
Message: <46f8e926@news.povray.org>
Ansgar <Tem### [at] gmxde> wrote:
> There you go. The object is not supposed to be seen through
> transparent/refractive objects.

  Then it's probably a bug in 3.7.

-- 
                                                          - Warp


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From: Chris Cason
Subject: Re: Problem with "no_image" and transparency?
Date: 25 Sep 2007 19:17:43
Message: <46f99717@news.povray.org>
Ansgar wrote:
> I just went through the POV-Ray help and found this in the section about
> "no_image".
> 
> "When no_image is used, the object will not be seen by the camera, either
> directly or through transparent/refractive objects. However, it will still
> cast shadows, and show up in reflections (unless no_reflection and/or
> no_shadow is used also)."
> 
> There you go. The object is not supposed to be seen through
> transparent/refractive objects.

Please post a minimal sample scene for us to work with.

thanks,

-- Chris


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From: Alain
Subject: Re: Problem with "no_image" and transparency?
Date: 26 Sep 2007 09:17:46
Message: <46fa5bfa$1@news.povray.org>
Chris Cason nous apporta ses lumieres en ce 2007/09/25 19:17:
> Ansgar wrote:
>> I just went through the POV-Ray help and found this in the section about
>> "no_image".
>>
>> "When no_image is used, the object will not be seen by the camera, either
>> directly or through transparent/refractive objects. However, it will still
>> cast shadows, and show up in reflections (unless no_reflection and/or
>> no_shadow is used also)."
>>
>> There you go. The object is not supposed to be seen through
>> transparent/refractive objects.
> 
> Please post a minimal sample scene for us to work with.
> 
> thanks,
> 
> -- Chris
As minimal as you can:

plane{z, 15 pigment{checker}finish{ambient 1} no_image}
sphere{<0,0,3>,1 pigment{rgbt 1}}

It should be all black but you see the checker pigment through the sphere.

-- 
Alain
-------------------------------------------------
Documentation; The worst part of programming.


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From: Le Forgeron
Subject: Re: Problem with "no_image" and transparency?
Date: 26 Sep 2007 11:41:42
Message: <46fa7db6@news.povray.org>
Le 26.09.2007 15:17, Alain nous fit lire :

> As minimal as you can:
> 
> plane{z, 15 pigment{checker}finish{ambient 1} no_image}
> sphere{<0,0,3>,1 pigment{rgbt 1}}
> 
> It should be all black but you see the checker pigment through the sphere.
> 
does it mean we need no_transmission and no_refraction also ?

-- 
The superior man understands what is right;
the inferior man understands what will sell.
-- Confucius


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From: Alain
Subject: Re: Problem with "no_image" and transparency?
Date: 26 Sep 2007 14:56:50
Message: <46faab72$1@news.povray.org>
Le Forgeron nous apporta ses lumieres en ce 2007/09/26 11:41:
> Le 26.09.2007 15:17, Alain nous fit lire :
> 
>> As minimal as you can:
>>
>> plane{z, 15 pigment{checker}finish{ambient 1} no_image}
>> sphere{<0,0,3>,1 pigment{rgbt 1}}
>>
>> It should be all black but you see the checker pigment through the sphere.
>>
> does it mean we need no_transmission and no_refraction also ?
> 
No. Just make no_image work coherently between versions, and according to the 
documentations.

An object with no_image is normaly invisible, but still cast shadows and show in 
reflections.

An object with no_reflection is visible, cast shadow, but don't show in reflections.

An object with no_shadow is visible normaly and in reflections but don't cast 
any shadow.

-- 
Alain
-------------------------------------------------
WARNING: The consumption of alcohol is a major factor in dancing like a retard.


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From: Nicolas Alvarez
Subject: Re: Problem with "no_image" and transparency?
Date: 29 Sep 2007 16:55:05
Message: <46febba9@news.povray.org>
Alain escribió:
> Le Forgeron nous apporta ses lumieres en ce 2007/09/26 11:41:
>> Le 26.09.2007 15:17, Alain nous fit lire :
>> does it mean we need no_transmission and no_refraction also ?
>>
 >
> No. Just make no_image work coherently between versions, and according 
> to the documentations.
> 

Why not? We could have no_image work coherently between versions and new 
no_transmission and no_refraction keywords too ;-)


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From: Alain
Subject: Re: Problem with "no_image" and transparency?
Date: 29 Sep 2007 21:39:05
Message: <46fefe39@news.povray.org>
Nicolas Alvarez nous apporta ses lumieres en ce 2007/09/29 16:57:
> Alain escribió:
>> Le Forgeron nous apporta ses lumieres en ce 2007/09/26 11:41:
>>> Le 26.09.2007 15:17, Alain nous fit lire :
>>> does it mean we need no_transmission and no_refraction also ?
>>>
>  >
>> No. Just make no_image work coherently between versions, and according 
>> to the documentations.
>>
> 
> Why not? We could have no_image work coherently between versions and new 
> no_transmission and no_refraction keywords too ;-)
You could add those, yes, but you don't need to.
no_transmition would work relative to transparent objects that don't have an 
ior. You don't see the object through a transparent object, but will see it 
through one with an ior.
no_refraction would work for those that do have an ior. You see that through a 
transparent object but not if that object have any ior different than 1.

-- 
Alain
-------------------------------------------------
Idolism: Let's bronze this shit.


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From: Chris Cason
Subject: Re: Problem with "no_image" and transparency?
Date: 11 May 2008 08:35:35
Message: <4826e817$1@news.povray.org>
Alain wrote:
> plane{z, 15 pigment{checker}finish{ambient 1} no_image}
> sphere{<0,0,3>,1 pigment{rgbt 1}}
> 
> It should be all black but you see the checker pigment through the sphere.

This is fixed in beta 26 (better late than never ;)

-- Chris


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