I have created a paper on PovRay and have mapped a scanned newspaper onto
it. Now, the scanned newpaper appears on both sides on the newspaper.
Oneside is what I want and the other side is in reverse. I'd like to keep
the other side blank AND/OR and different image map on the other side. Can
anyone guide me to the two different possibilities?

BR/Saadat Saeed

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Saadat Saeed wrote:
> 
> I have created a paper on PovRay and have mapped a scanned newspaper onto
> it. Now, the scanned newpaper appears on both sides on the newspaper.
> Oneside is what I want and the other side is in reverse. I'd like to keep
> the other side blank AND/OR and different image map on the other side. Can
> anyone guide me to the two different possibilities?
> 
> BR/Saadat Saeed

Use two papers, one with image_map the other without (or with a different one)
and slightly translate the second down (relative to its orientation).

Good luck,

Remco

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Just to confirm, if I can, I believe Remco has the only answer there
is for that.  All objects are sort of one-sided while also being
double-sided, if that makes any sense. At least for the purposes of
texturing.  Takes the two objects then to make a true piece of paper.
Semi-transparency is another matter, in which case you'd want to make
the underside page a little filtered.

Bob

Remco de Korte <rem### [at] xs4allnl> wrote in message
news:37DB8166.CF82B685@xs4all.nl...
> Saadat Saeed wrote:
> >
> > I have created a paper on PovRay and have mapped a scanned
newspaper onto
> > it. Now, the scanned newpaper appears on both sides on the
newspaper.
> > Oneside is what I want and the other side is in reverse. I'd like
to keep
> > the other side blank AND/OR and different image map on the other
side. Can
> > anyone guide me to the two different possibilities?
> >
> > BR/Saadat Saeed
>
> Use two papers, one with image_map the other without (or with a
different one)
> and slightly translate the second down (relative to its
orientation).
>
> Good luck,
>
> Remco

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On Sun, 12 Sep 1999 12:35:05 -0500, Bob Hughes <inv### [at] aolcom> wrote:
>Just to confirm, if I can, I believe Remco has the only answer there
>is for that.  All objects are sort of one-sided while also being
>double-sided, if that makes any sense. At least for the purposes of
>texturing.  Takes the two objects then to make a true piece of paper.
>Semi-transparency is another matter, in which case you'd want to make
>the underside page a little filtered.

And yet we POV-Ray users feel free to comment on the fact that people
who use other modeling programs feel the need to double up mesh faces.
Aren't we a bunch of hypocrites. :)

Seriously, there is another way to get different textures on both sides
of a sheet of paper, but it's a little more difficult.  It requires 
you to use a radial texture, and it requires the paper to have at least
a little thickness so as to prevent weirdness in the texture.  If you're
using a patch object for the paper, I think I'd recommend doubling it
up as previously suggested.

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Ron Parker wrote:
> 
 
> Seriously, there is another way to get different textures on both sides
> of a sheet of paper, but it's a little more difficult.  It requires
> you to use a radial texture, and it requires the paper to have at least
> a little thickness so as to prevent weirdness in the texture.  If you're
> using a patch object for the paper, I think I'd recommend doubling it
> up as previously suggested.

I wonder: if it's a flat box would it work if you used a gradient pigment with
two image maps?
Something like:
pigment{
  gradient y
  pigment_map{
    [0 image1]
    [0.49 image1]
    [0.51 image2]
    [1 image2]
  }
}

Forgive the syntax-mistakes, I haven't tried this...

Remco

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There are pathological cases when the doubling method is practically impossible.

I wonder... Would it be difficult to implement separate textures for the two
sides of a surface? I.e. when the surface normal is >90 degrees from the current
ray, use one texture - and when <90 degrees use another. Sound simple, at least
in principle.

Margus

Ron Parker wrote:
> 
> Seriously, there is another way to get different textures on both sides
> of a sheet of paper, but it's a little more difficult.  It requires
> you to use a radial texture, and it requires the paper to have at least
> a little thickness so as to prevent weirdness in the texture.  If you're
> using a patch object for the paper, I think I'd recommend doubling it
> up as previously suggested.

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That would not be difficult at all, in fact, I was about to make an
"interior_texture" patch when this message came up. :-)
I have already done something similar for a reflection patch I did, to
make one-way mirrors, but this method will be much more versatile. My
patch was limited to specifying the reflection for the interior side of
the surface.
Oh, before you ask-this patch should work for triangles, beziers, etc,
because although they don't have an interior, they are two-sided shapes.

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On Mon, 13 Sep 1999 06:44:42 -0500, Chris Huff wrote:
>That would not be difficult at all, in fact, I was about to make an
>"interior_texture" patch when this message came up. :-)
>I have already done something similar for a reflection patch I did, to
>make one-way mirrors, but this method will be much more versatile. My
>patch was limited to specifying the reflection for the interior side of
>the surface.

One small note - beware the code that flips surface normals for shading 
purposes.  It might confuse your patch if it happens in the wrong place.

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: ) I was going to say the same thing when I saw Ron's "more
difficult" texturing method.  So THAT's why I saw someone mention
Ron's extravagant use of the radial pattern!
Anyway, for flat objects fine, but sounds like the need for isosurface
and isopigments to me if doing wrinkled or otherwise misshaped base
objects.

Bob

Remco de Korte <rem### [at] xs4allnl> wrote in message
news:37DCCE82.7DBB51CE@xs4all.nl...
> Ron Parker wrote:
> >
>
> > Seriously, there is another way to get different textures on both
sides
> > of a sheet of paper, but it's a little more difficult.  It
requires
> > you to use a radial texture, and it requires the paper to have at
least
> > a little thickness so as to prevent weirdness in the texture.  If
you're
> > using a patch object for the paper, I think I'd recommend doubling
it
> > up as previously suggested.
>
> I wonder: if it's a flat box would it work if you used a gradient
pigment with
> two image maps?
> Something like:
> pigment{
>   gradient y
>   pigment_map{
>     [0 image1]
>     [0.49 image1]
>     [0.51 image2]
>     [1 image2]
>   }
> }
>
> Forgive the syntax-mistakes, I haven't tried this...
>
> Remco

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On Mon, 13 Sep 1999 09:03:11 -0500, Bob Hughes wrote:
>: ) I was going to say the same thing when I saw Ron's "more
>difficult" texturing method.  So THAT's why I saw someone mention
>Ron's extravagant use of the radial pattern!

If you saw someone make a comment about my extravagant use of the
radial pattern, it was probably in reference to either my hextiles
or my star pigments.  That particular application of radial, to 
texture both sides of an object differently, is something I picked 
up from someone else; I think it was Chris Colefax.

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