POV-Ray : Newsgroups : povray.newusers : the background color : can it be faked ? Server Time
1 Nov 2024 19:14:43 EDT (-0400)
  the background color : can it be faked ? (Message 1 to 6 of 6)  
From: Hal
Subject: the background color : can it be faked ?
Date: 21 Feb 2005 10:30:00
Message: <web.4219fe5796c27f36a655690@news.povray.org>
i dont know if this has a solution , but i hope so ...

imagine that i have some metal letters (say T_Chrome_5E ) in the middle of
space , with just 2 or 3 lights more , and whithout any other object or
plain

the letters will shine a lot , and we will see metal letters with a black
background

but i want to make the same letters , with a white background,

so i would add :    background {color rgb <1,1,1> }

but the problem is that the reaction wont be the same , bcoz its everything
in white, and the letters wont even be visible , bcoz the scene shines too
much !!!


so .... my question is ....  can i make a scene reacting to a black
backgroung , but with a white background visible ?

i could make it with a black background and then , using a good software
like photoshop to fill the black around the letters with white , but  the
edges of the letters would be too much aliased ....
its very very hard to fill the space around the letters with white properly
.....

any help ?

or it cant do done ?    :(

*sorry for my english ... i only had 2 years of english at my school .... :(
*


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From: Marc Jacquier
Subject: Re: the background color : can it be faked ?
Date: 21 Feb 2005 10:48:19
Message: <421a02c3$1@news.povray.org>

news:web.4219fe5796c27f36a655690@news.povray.org...
If what worries you is the  background reflections in the letters, you could
try to put a  white plane behind the letters with the keyword no_reflection
so it doesn't reflects in the letters

plane{-z, 100 // or any orientation or distance you want
texture{
            pigment{color rgb 1}
            finish{ambient 1 diffuse 0}// not light-dependant
            }
no_reflection
}

Another way is to choose an output file format that supports alpha channel
( transparency channel) and put  +UA in your command line (or "Output_Alpha=
on" in your .ini file)
TGA and PNG support alpha channel.
render with a black background.
Then you can paste your output file including alpha channel on a white
background in an image editing software

Hope that helps

Marc


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From: Hal
Subject: Re: the background color : can it be faked ?
Date: 21 Feb 2005 11:05:01
Message: <web.421a058a37532c7aa655690@news.povray.org>
so , in the case of a white plane in the back of my scene , i would get a
white background (from the plane) , but that plane wouldnt change anything
in the scene bcoz it has no_reflection keyword , right ?

so , i see a white plane , but the plane its not really in there, right ?

i forgot that ....  :)

tanks .. i'll try that ....


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From: Marc Jacquier
Subject: Re: the background color : can it be faked ?
Date: 21 Feb 2005 11:14:47
Message: <421a08f7@news.povray.org>

news:web.421a058a37532c7aa655690@news.povray.org...
> so , in the case of a white plane in the back of my scene , i would get a
> white background (from the plane) , but that plane wouldnt change anything
> in the scene bcoz it has no_reflection keyword , right ?
>
> so , i see a white plane , but the plane its not really in there, right ?
>
> i forgot that ....  :)
>
> tanks .. i'll try that ....
>
>
>
The plane just does not reflect anywhere but it can been seen directly or in
refractions,
 influence radiosity, cast shadow, hide other objects... all but
reflection...
 as a vampire in a mirror  (though I don't think garlic, a sharpened wood
stick or a cross have any power against your plane ;-)

Marc


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From: Hal
Subject: Re: the background color : can it be faked ?
Date: 21 Feb 2005 11:20:01
Message: <web.421a096a37532c7aa655690@news.povray.org>
but i also need to add the no_shadow keyword , right ?

so i can make a think such as this one :

a plane visible that doesnt change a thing in the scene, right ?

http://img128.exs.cx/img128/3959/wineglass9qg.jpg


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From: Marc Jacquier
Subject: Re: the background color : can it be faked ?
Date: 21 Feb 2005 11:26:07
Message: <421a0b9f@news.povray.org>

news:web.421a096a37532c7aa655690@news.povray.org...
> but i also need to add the no_shadow keyword , right ?
>
> so i can make a think such as this one :
>
> a plane visible that doesnt change a thing in the scene, right ?
>
> http://img128.exs.cx/img128/3959/wineglass9qg.jpg
>
>
Well if you have no light behind your plane no_shadow is useless, if you
have one or more , it is usefull of course.
Marc


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