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  A Question about Image Maps (Message 1 to 6 of 6)  
From: Wykan
Subject: A Question about Image Maps
Date: 21 Apr 1998 15:56:53
Message: <01bd6d5f$83df1d80$24f239d1@wykan.siscom.net>
Okay, I've figured out how to use image maps to apply pre-existing images
to POV objects as surface pigments. And I've figured out the difference
between the three currently available image map types.

What I can't figure out is how to apply an image map to an irregular shape
without distorting portions of the image. I want to take a .gif (an actual
map of the world, not that it matters) and put it on an object (a map, of
course) laying in a drawer, such that part of it is laying flat within the
drawer, part of it curls up over the faceplate of the drawer, and the rest
is hanging down out of the drawer.

The obvious problem is that the various surfaces of the map object are at
severe angles to one another. When I try to apply the image map, whichever
surface was upright (facing the z-axis) will get mapped properly, and all
the rest gets distorted.

Can anyone help me with this?


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From: Jon A  Cruz
Subject: Re: A Question about Image Maps
Date: 21 Apr 1998 16:25:02
Message: <353D009E.8E50B933@geocities.com>
I've seen a method in a tutorial that might work in some cases. Start
with an image map that is some sort of grid (squares of assorted colors
are good) and render that on the object. Then see where the squares fall
and create a distorted map that maps out to what you want.


Wykan wrote:
> 
> Okay, I've figured out how to use image maps to apply pre-existing images
> to POV objects as surface pigments. And I've figured out the difference
> between the three currently available image map types.
> 
> What I can't figure out is how to apply an image map to an irregular shape
> without distorting portions of the image. I want to take a .gif (an actual
> map of the world, not that it matters) and put it on an object (a map, of
> course) laying in a drawer, such that part of it is laying flat within the
> drawer, part of it curls up over the faceplate of the drawer, and the rest
> is hanging down out of the drawer.
> 
> The obvious problem is that the various surfaces of the map object are at
> severe angles to one another. When I try to apply the image map, whichever
> surface was upright (facing the z-axis) will get mapped properly, and all
> the rest gets distorted.
> 
> Can anyone help me with this?


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From: Jerry Anning
Subject: Re: A Question about Image Maps
Date: 21 Apr 1998 17:23:49
Message: <353D0E64.38CCB228@dhol.com>
Wykan wrote:
> 
> Okay, I've figured out how to use image maps to apply pre-existing images
> to POV objects as surface pigments. And I've figured out the difference
> between the three currently available image map types.
> 
> What I can't figure out is how to apply an image map to an irregular shape
> without distorting portions of the image. I want to take a .gif (an actual
> map of the world, not that it matters) and put it on an object (a map, of
> course) laying in a drawer, such that part of it is laying flat within the
> drawer, part of it curls up over the faceplate of the drawer, and the rest
> is hanging down out of the drawer.
> 
> The obvious problem is that the various surfaces of the map object are at
> severe angles to one another. When I try to apply the image map, whichever
> surface was upright (facing the z-axis) will get mapped properly, and all
> the rest gets distorted.
> 
> Can anyone help me with this?

What you want to do is called "uv mapping".  Standard POV does not yet
do this.  The Isosurface patch version of POV can do it. Get it at:

http://www.public.usit.net/rsuzuki/e/povray/iso/index.html

or

http://www.etl.go.jp/~rsuziki/e/povray/iso/index.html

Jerry Anning
cle### [at] dholcom


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From: Wykan
Subject: Isosurface Patch for POV
Date: 22 Apr 1998 02:42:10
Message: <01bd6db9$a82ada80$17f239d1@wykan.siscom.net>
Many thanks for the tip! I have downloaded the patch already, and will let
you all know whether I can get it to work. (I have no doubt about ITS
abilities ... )


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From: POVRAY
Subject: Re: Isosurface Patch for POV
Date: 22 Apr 1998 07:28:32
Message: <353DD460.C1350AC6@aol.com>
You may also want to pick up sPatch since, last I tried it, the isosurface
patch only did uv mapping with bezier patches.

-Mike

Wykan wrote:

> Many thanks for the tip! I have downloaded the patch already, and will let
> you all know whether I can get it to work. (I have no doubt about ITS
> abilities ... )


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From: Wykan
Subject: Re: Isosurface Patch for POV
Date: 23 Apr 1998 13:44:52
Message: <01bd6edf$653cfce0$03f239d1@wykan.siscom.net>
Fortunately, I already have sPatch -- it was the only thing that let me
create the map object in the shape I wanted, without having to make an
incredibly complex CSG object (which I also tried, and soon gave up on).

POVRAY <POV### [at] aolcom> wrote in article <353DD460.C1350AC6@aol.com>...
> You may also want to pick up sPatch since, last I tried it, the
isosurface
> patch only did uv mapping with bezier patches.
> 
> -Mike


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