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this is me <nomail@nomail> wrote:
> I'd like my objects to be against a transparent background to make compositing
> within a video editor much easier, but I'm not sure POVRAY can be set up to do
> this. Any thoughts?
Use the command-line option +ua (in the Windows version you can write
command-line options on the textfield at the top of the window, at the
right of the resolution selection dropdown menu) and use as output an
image format which supports alpha channel, such as png (+fn) or tga (+ft).
--
- Warp
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>
> Use the command-line option +ua (in the Windows version you can write
> command-line options on the textfield at the top of the window, at the
> right of the resolution selection dropdown menu) and use as output an
> image format which supports alpha channel, such as png (+fn) or tga (+ft).
>
> --
>
- Warp
I have the same question as the original post...
I have seen a lot of info about using "transmit" and making sure that I am
outputting a PNG or TGA but I have not had any success getting these things to
actually work.
I do not have a usable alpha channel when I open my image in photoshop.
When I export a TGA (by using "Output_File_Type=C") I get an "alpha" channel in
photoshop but it fills the entire image it does not apply only to the
background.
When I export a PNG (by using "Output_File_Type=N") I do not get an alpha
channel at all.
I am a total newbie to rendering but I am trying to stitch together enough
scenes to simulate a rotating model of a building and therefore it would be
great to not have ANY background behind the model.
I have attached some info from my POV file and my INI file that I am using to
render with:
POV FILE:
background{ color rgbt<0,0,0,1> }
INI FILE:
[4966x2464, AA 0.3]
Output_File_Type=N
Output_Alpha=on
Bits_Per_Color=8
Width=4966
Height=2464
Antialias=On
Antialias_Threshold=0.3
What do I have to do to get a truly transparent background?
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gbclemson <nomail@nomail> wrote:
> I have seen a lot of info about using "transmit" and making sure that I am
> outputting a PNG or TGA but I have not had any success getting these things to
> actually work.
"transmit" has nothing to do with the output file alpha channel (I really
don't understand where you or anyone else got that idea). What you need is:
1) Use the command-line option +ua
2) Output to an image format that supports alpha channel, such as
png or tga.
3) Have some visible background on your scene (in other words, parts
of the image which do not have *anything* at all, just empty background).
Example scene:
//-------------------------------------------------------------------------
camera { location -z*5 look_at 0 angle 35 }
light_source { <100, 200, -300>, 1 }
sphere
{ 0, 1
pigment { rgb <1, 0, 0> }
finish { specular .5 }
}
//-------------------------------------------------------------------------
I rendered that scene at 320x240, using antialiasing and +ua, and
outputting to a png file, and the result was:
http://warp.povusers.org/images/test.png
If your image manipulation program cannot correctly read the alpha
channel from that image file, then your image manipulation program is
broken.
--
- Warp
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