POV-Ray : Newsgroups : povray.newusers : render on transparent background ? Server Time
13 Nov 2024 03:49:38 EST (-0500)
  render on transparent background ? (Message 1 to 10 of 10)  
From: Lothar Esser
Subject: render on transparent background ?
Date: 23 Apr 2001 16:59:47
Message: <3AE497C5.83697719@helix.nih.gov>
Hi,

  I would like to know if it is possible to render an image on
transparent background. Initially I thought of
something like background {color <1,1,1> transmit 1} but it does not
seem to work ( background is still white )
I know that I can post-process an image by using say ImageMagick and set
all white background pixels to fully transparent. However I would like
to skip this extra step if possible.

Thanks.

Lothar.

--
Dr. Lothar Esser
NIH / NCI
Tel. 301-435-6163
email les### [at] helixnihgov


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From: Ron Parker
Subject: Re: render on transparent background ?
Date: 23 Apr 2001 17:03:28
Message: <slrn9e9652.3ri.ron.parker@fwi.com>
On Mon, 23 Apr 2001 16:59:49 -0400, Lothar Esser wrote:
>Hi,
>
>  I would like to know if it is possible to render an image on
>transparent background. Initially I thought of
>something like background {color <1,1,1> transmit 1} but it does not
>seem to work ( background is still white )
>I know that I can post-process an image by using say ImageMagick and set
>all white background pixels to fully transparent. However I would like
>to skip this extra step if possible.

You might try rendering to a format that supports an alpha channel, and
turn on the +UA option.  Beware, though, that antialiasing will introduce
a "fringe" of your background color.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.


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From: Lothar Esser
Subject: Re: render on transparent background ?
Date: 23 Apr 2001 18:02:43
Message: <3AE4A686.2FD2273B@helix.nih.gov>
Ron Parker wrote:

> On Mon, 23 Apr 2001 16:59:49 -0400, Lothar Esser wrote:
> >Hi,
> >
> >  I would like to know if it is possible to render an image on
> >transparent background. Initially I thought of
> >something like background {color <1,1,1> transmit 1} but it does not
> >seem to work ( background is still white )
> >I know that I can post-process an image by using say ImageMagick and set
> >all white background pixels to fully transparent. However I would like
> >to skip this extra step if possible.
>
> You might try rendering to a format that supports an alpha channel, and
> turn on the +UA option.  Beware, though, that antialiasing will introduce
> a "fringe" of your background color.
>
> --
> Ron Parker   http://www2.fwi.com/~parkerr/traces.html
> My opinions.  Mine.  Not anyone else's.

Excellent, thanks a bundle !

--
Dr. Lothar Esser
NIH / NCI
Tel. 301-435-6163
email les### [at] helixnihgov


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From: Warp
Subject: Re: render on transparent background ?
Date: 24 Apr 2001 06:37:11
Message: <3ae55757@news.povray.org>
Ron Parker <ron### [at] povrayorg> wrote:
: You might try rendering to a format that supports an alpha channel, and
: turn on the +UA option.  Beware, though, that antialiasing will introduce
: a "fringe" of your background color.

  I think this will be fixed.

-- 
#local D=array[6]{11117333955,7382340,3358,3900569407,970,4254934330}
#local I=0;#macro M()<mod(D[I],13)-6,mod(div(D[I],13),8)-3,10>#end
#while(I<6)cylinder{M()#local D[I]=div(D[I],104);M().1
pigment{rgb M()}}#local I=(D[I]>99?I:I+1);#end              /*- Warp -*/


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From: Ron Parker
Subject: Re: render on transparent background ?
Date: 24 Apr 2001 09:19:13
Message: <slrn9eavaj.48d.ron.parker@fwi.com>
On 24 Apr 2001 06:37:11 -0400, Warp wrote:
>Ron Parker <ron### [at] povrayorg> wrote:
>: You might try rendering to a format that supports an alpha channel, and
>: turn on the +UA option.  Beware, though, that antialiasing will introduce
>: a "fringe" of your background color.
>
>  I think this will be fixed.

It's true that this has been fixed in 3.5, but 3.5 isn't the current version
yet.  I thought it might be useful to give fair warning for those who are
using today's version today.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.


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From: Warp
Subject: Re: render on transparent background ?
Date: 24 Apr 2001 09:24:47
Message: <3ae57e9f@news.povray.org>
Ron Parker <ron### [at] povrayorg> wrote:
: It's true that this has been fixed in 3.5, but 3.5 isn't the current version
: yet.  I thought it might be useful to give fair warning for those who are
: using today's version today.

  That's why I used the future tense. I also think that it's equally fair
to tell that the problem is known and will be fixed :)

-- 
#local D=array[6]{11117333955,7382340,3358,3900569407,970,4254934330}
#local I=0;#macro M()<mod(D[I],13)-6,mod(div(D[I],13),8)-3,10>#end
#while(I<6)cylinder{M()#local D[I]=div(D[I],104);M().1
pigment{rgb M()}}#local I=(D[I]>99?I:I+1);#end              /*- Warp -*/


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From: Ron Parker
Subject: Re: render on transparent background ?
Date: 24 Apr 2001 09:27:49
Message: <slrn9eavqn.48d.ron.parker@fwi.com>
On 24 Apr 2001 09:24:47 -0400, Warp wrote:
>Ron Parker <ron### [at] povrayorg> wrote:
>: It's true that this has been fixed in 3.5, but 3.5 isn't the current version
>: yet.  I thought it might be useful to give fair warning for those who are
>: using today's version today.
>
>  That's why I used the future tense. I also think that it's equally fair
>to tell that the problem is known and will be fixed :)

Fair enough.

Though as long as we're talking tenses, the correct tense is "has been fixed."
Six months ago. :)

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.


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From: Warp
Subject: Re: render on transparent background ?
Date: 24 Apr 2001 09:42:35
Message: <3ae582cb@news.povray.org>
Ron Parker <ron### [at] povrayorg> wrote:
: Though as long as we're talking tenses, the correct tense is "has been fixed."
: Six months ago. :)

  Well, I was talking from the point of view of a user. That is, more like
"the problem you are having will be fixed when the new version is published".

-- 
#local D=array[6]{11117333955,7382340,3358,3900569407,970,4254934330}
#local I=0;#macro M()<mod(D[I],13)-6,mod(div(D[I],13),8)-3,10>#end
#while(I<6)cylinder{M()#local D[I]=div(D[I],104);M().1
pigment{rgb M()}}#local I=(D[I]>99?I:I+1);#end              /*- Warp -*/


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From: Lothar Esser
Subject: Re: render on transparent background ?
Date: 24 Apr 2001 10:46:54
Message: <3AE591E0.76A78D61@helix.nih.gov>
Warp wrote:

> Ron Parker <ron### [at] povrayorg> wrote:
> : Though as long as we're talking tenses, the correct tense is "has been fixed."
> : Six months ago. :)
>
>   Well, I was talking from the point of view of a user. That is, more like
> "the problem you are having will be fixed when the new version is published".

Since you guys seem to know what the future holds, may I ask whether the features
that I need will be available in some form in version 3.5 or 4.0 or 4.5 or 5.0 or
5.5 ..?

L.


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From: Warp
Subject: Re: render on transparent background ?
Date: 24 Apr 2001 14:25:06
Message: <3ae5c502@news.povray.org>
Lothar Esser <les### [at] helixnihgov> wrote:
: Since you guys seem to know what the future holds, may I ask whether the features
: that I need will be available in some form in version 3.5 or 4.0 or 4.5 or 5.0 or
: 5.5 ..?

  Rendering with alpha channel is already available in 3.1.
  A slightly fixed version will be available with 3.5.

  (The fix is that the color of the background should not affect the
color of a partially transparent pixel when using alpha channel, as the
background has no color in this case (it's transparent). This is
situation happens mainly with antialiasing.)

-- 
#local D=array[6]{11117333955,7382340,3358,3900569407,970,4254934330}
#local I=0;#macro M()<mod(D[I],13)-6,mod(div(D[I],13),8)-3,10>#end
#while(I<6)cylinder{M()#local D[I]=div(D[I],104);M().1
pigment{rgb M()}}#local I=(D[I]>99?I:I+1);#end              /*- Warp -*/


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