I have a problem that I need help with!
I have a image map that has a white background that I am trying to make
transparent. The index of the color is 0 so I am using "filter 0,1".
povray 3.1 makes the background transparent ok; but it leaves an
artifact of the box or plane that it is mapped to, like the transparent
part is refracting the light or something. How do I get rid of the
artifact so that the only thing left is the non transparent part of the
image?

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James Wood wrote:
> 
> I have a problem that I need help with!
> I have a image map that has a white background that I am trying to make
> transparent. The index of the color is 0 so I am using "filter 0,1".
> povray 3.1 makes the background transparent ok; but it leaves an
> artifact of the box or plane that it is mapped to, like the transparent
> part is refracting the light or something. How do I get rid of the
> artifact so that the only thing left is the non transparent part of the
> image?

I devised a simple test for this and was unable to duplicate your problem.
I made a simple image with a black dot on a white background. I then named
it itest.gif and saved it as a 256 color gif image - in my case the black
index is zero and the white index is 215. Using the scene code below the
box was completely transparent except for were the black dot was in the
image. Perhaps if you could paste in the problem part of your code we
might be able to see if it is a proceedural problem. The only other thing
I can think of is that your image background is not completely solid and
your artifacts are caused by this. Also mention what image format your
image_map image is, color depth, and what platform and version of POV-Ray
you are running.

background{rgb 1}

camera {location <0, 0, -3 >look_at  0}

box{-0.5,0.5 pigment{image_map{ gif "imap.gif" filter 215, 1}translate -0.5}}

light_source{< 0, 0, -29>rgb<1,1,1>}

-- 
Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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Try making the box in fluege2 hollow, or try replacing it with two triangles.
The media won't appear because the box is technically closed, and has an
interior that is unaffected by the media

James Wood wrote:

> James Wood wrote:
> >
> > I have a problem that I need help with!
> > I have a image map that has a white background that I am trying to make
> > transparent. The index of the color is 0 so I am using "filter 0,1".
> > povray 3.1 makes the background transparent ok; but it leaves an
> > artifact of the box or plane that it is mapped to, like the transparent
> > part is refracting the light or something. How do I get rid of the
> > artifact so that the only thing left is the non transparent part of the
> > image?
>
> This is the entire scene file. The only difference is that the index has
> changed from 0 to 255. attached is the scene that this creates. also
> attached is the gif file for the image map
>
> <snip>
> #declare wing_file2="c:\images\vbutterfly.gif"  //wing texture file
>
>    #declare wing_angle = 40
>   #declare scale_butterfly = .5
>  #declare trans_butterfly = <0,0,0>
>  #declare rotate_butterfly = <0,0,0>
> #declare fluege2=box{<0,0,0>,<1,1,0>
>  pigment{
>   image_map{
>    gif wing_file2
>    filter 255,1
>      }
>    }
>    finish{ambient 0.0}
>    finish{diffuse 1}
>    scale <0.5596,1,1>
>    translate<-0.5796,0,0>
>  }
>
> <snip>

--
Josh English
eng### [at] spiritonecom
"May your hopes, dreams, and plans not be destroyed by a few zeros."

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This is not a GIF transparency issue. You need to add 'hollow' to the union
"butterfly2" otherwise the media showing through it is not rendered, which
causes the artifact you see.

Also, you should not post a scene file or a binary attachment in this group.
Please see povray.announce.frequently-asked-questions for posting guidelines on
this server.
It would be polite to at least try to make the example scene shorter and easier
to read.

Margus

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Thank you for your quick response. It worked generally; now to put the
thing inside a glass ball or globe it comes back. Now how do I get rid
of it?

Margus Ramst wrote:
> 
> This is not a GIF transparency issue. You need to add 'hollow' to the union
> "butterfly2" otherwise the media showing through it is not rendered, which
> causes the artifact you see.
> 
> Also, you should not post a scene file or a binary attachment in this group.
> Please see povray.announce.frequently-asked-questions for posting guidelines on
> this server.
> It would be polite to at least try to make the example scene shorter and easier
> to read.
> 
> Margus

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How about:
global_settings { max_trace_level 10 }
will that make any difference in it?
I saw that you fixed the missing 'hollow'.  Is there filtered or transmitted
color in the glass?

You should try to cancel your binary attachment post, please.

Bob

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This time, I suspect your problem is too low max_trace_level.
If your glass globe is constructed of a difference of 2 spheres, you need a
max_trace_level of at least 5 to see through it (this the default level). Add 
butterfly wings and the required max_trace_level is 6.
You can check the render statistics, it contains the 'Max Level' entry. The
first number here is the minimum required level. Second is the level you are
currently using.

Margus

James Wood wrote:
> 
> Thank you for your quick response. It worked generally; now to put the
> thing inside a glass ball or globe it comes back. Now how do I get rid
> of it?
>

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I finally got it to work.

Hollow worked for the images outside the glass globe, but when I put
them inside the globe the transparent part of the images wanted to
refract the light soooooo I set interior ior to the same as the globe
and the artifacts went away. Thanks people for all your help.   I will
be an expert sooooooon. (Hopefully)

As far as canceling the binary posts in this newsgroup; can any one
advise me as to how to do that. Once I know; I surely will do so, Thanks
again
JW

Bob Hughes wrote:
> 
> How about:
> global_settings { max_trace_level 10 }
> will that make any difference in it?
> I saw that you fixed the missing 'hollow'.  Is there filtered or transmitted
> color in the glass?
> 
> You should try to cancel your binary attachment post, please.
> 
> Bob

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James Wood wrote:

> As far as canceling the binary posts in this newsgroup; can any one
> advise me as to how to do that. Once I know; I surely will do so, Thanks
> again
> JW

It appears you are using Netscape so I can advise you on this one.
open the message with the binary attachement. Right click on the
message body and a menu will pop up with several choices. Choose
"cancel message". A dialog should appear asking if you are sure
that you want to cancel this message. Choose yes. The message
should now be deleted. 

-- 
Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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You can also right-click on the message title in the message list, and select
'cancel' from there.

Margus

Ken wrote:
> 
> It appears you are using Netscape so I can advise you on this one.
> open the message with the binary attachement. Right click on the
> message body and a menu will pop up with several choices. Choose
> "cancel message". A dialog should appear asking if you are sure
> that you want to cancel this message. Choose yes. The message
> should now be deleted.
> 
> --
> Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
> http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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