Hi,

I_m trying to create an opaque texture. Does anybody have an idea
whether this is possible with povray,
and if yes how it works.

thanks a lot for a hint

Rainer

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Rainer Ludwig <Rai### [at] gmxnet> wrote:
: I_m trying to create an opaque texture.

  AFAIK all textures are opaque if you don't specify filter nor transmit in
their pigment.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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Hi,

thanks for the quick answer, so I expressed myself the wrong way. I'm talking
about texture that is translucent, but not transparent, i.e. if there would be
a light source behind it one would notice it, without seeing it.

That's the problem

ciao

Rainer

Nieminen Juha schrieb:

> Rainer Ludwig <Rai### [at] gmxnet> wrote:
> : I_m trying to create an opaque texture.
>
>   AFAIK all textures are opaque if you don't specify filter nor transmit in
> their pigment.
>
> --
> main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
> ):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

--
II*

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Rainer Ludwig <Rai### [at] gmxnet> wrote:
: thanks for the quick answer, so I expressed myself the wrong way. I'm talking
: about texture that is translucent, but not transparent, i.e. if there would be
: a light source behind it one would notice it, without seeing it.

  Sorry, I didn't understand what do you mean. I'm not sure if I know what's
the difference between transparency and translucency...

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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Hello,

Transparency: you see perfectly well the shape of the object but more or
less bright, clearly (sorry but english is not my language so I cannot
always say exactly what I think :)). This is like sunny glasses! this is
transparency but the glasses can be more or less transparent but you
will always see the object perflectly (the shape of the object will be
the same with or without the glasses). A tranparent object just change
the quantity of light you will received (ok if ior != 1 so the shape of
the object is modified, but for this discution suppose ior = 1, because
this is not the purpose here).

Translucency: the light is scattered. For example, imagine a light
behing something which is translucent. So you will see that there are
something luminous behind the object but you cannot tell and see the
shape of the object. Many lamp have something (I don't know the word)
translucent to not see directly the light.

Example: a simple sheet of paper is translucent, not transparent. Glass
(even dark brown glass) is transparent.

I think that translucent object is difficult to do. Any clue?

Thanks

Nieminen Juha wrote:
> 
> Rainer Ludwig <Rai### [at] gmxnet> wrote:
> : thanks for the quick answer, so I expressed myself the wrong way. I'm talking
> : about texture that is translucent, but not transparent, i.e. if there would be
> : a light source behind it one would notice it, without seeing it.
> 
>   Sorry, I didn't understand what do you mean. I'm not sure if I know what's
> the difference between transparency and translucency...
> 
> --
> main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
> ):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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Fabian Brau <fab### [at] umhacbe> wrote:
: Translucency: the light is scattered. For example, imagine a light
: behing something which is translucent. So you will see that there are
: something luminous behind the object but you cannot tell and see the
: shape of the object. Many lamp have something (I don't know the word)
: translucent to not see directly the light.

  I think that the lighting model used in povray does not support this
kind of effect. You might get some results in a few cases using tricks,
but I don't think you can do it in general.
  I don't think that this is because povray is limited, but it's because
raytracing is limited.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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Nieminen Juha wrote:
> 
> Fabian Brau <fab### [at] umhacbe> wrote:
> : Translucency: the light is scattered. For example, imagine a light
> : behing something which is translucent. So you will see that there are
> : something luminous behind the object but you cannot tell and see the
> : shape of the object. Many lamp have something (I don't know the word)
> : translucent to not see directly the light.
> 
>   I think that the lighting model used in povray does not support this
> kind of effect. You might get some results in a few cases using tricks,
> but I don't think you can do it in general.
>   I don't think that this is because povray is limited, but it's because
> raytracing is limited.

You might be able to simulate this effect using media but it would take
some experimenting to make it work. Candle wax is a good example of
something that has translucent properties.

-- 
Ken Tyler -  1200+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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Hello Ken,

yes candle wax is another example (there are plenty...). I have tried to
do this (it was for a friend). I didnt't try a long time but is not
simple :)!!

Fabian.

Ken wrote:
> 
> Nieminen Juha wrote:
> >
> > Fabian Brau <fab### [at] umhacbe> wrote:
> > : Translucency: the light is scattered. For example, imagine a light
> > : behing something which is translucent. So you will see that there are
> > : something luminous behind the object but you cannot tell and see the
> > : shape of the object. Many lamp have something (I don't know the word)
> > : translucent to not see directly the light.
> >
> >   I think that the lighting model used in povray does not support this
> > kind of effect. You might get some results in a few cases using tricks,
> > but I don't think you can do it in general.
> >   I don't think that this is because povray is limited, but it's because
> > raytracing is limited.
> 
> You might be able to simulate this effect using media but it would take
> some experimenting to make it work. Candle wax is a good example of
> something that has translucent properties.
> 
> --
> Ken Tyler -  1200+ Povray, Graphics, 3D Rendering, and Raytracing Links:
> http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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this seems sort of like something you'd want to do using radiosity or something.

Fabian Brau wrote:

> Hello Ken,
>
> yes candle wax is another example (there are plenty...). I have tried to
> do this (it was for a friend). I didnt't try a long time but is not
> simple :)!!
>
> Fabian.
>
> Ken wrote:
> >
> > Nieminen Juha wrote:
> > >
> > > Fabian Brau <fab### [at] umhacbe> wrote:
> > > : Translucency: the light is scattered. For example, imagine a light
> > > : behing something which is translucent. So you will see that there are
> > > : something luminous behind the object but you cannot tell and see the
> > > : shape of the object. Many lamp have something (I don't know the word)
> > > : translucent to not see directly the light.
> > >
> > >   I think that the lighting model used in povray does not support this
> > > kind of effect. You might get some results in a few cases using tricks,
> > > but I don't think you can do it in general.
> > >   I don't think that this is because povray is limited, but it's because
> > > raytracing is limited.
> >
> > You might be able to simulate this effect using media but it would take
> > some experimenting to make it work. Candle wax is a good example of
> > something that has translucent properties.
> >
> > --
> > Ken Tyler -  1200+ Povray, Graphics, 3D Rendering, and Raytracing Links:
> > http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/



--
The problem with the gene pool is that there is no lifeguard.

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> this seems sort of like something you'd want to do using radiosity
> or something.
 
yes... but radiosity doesn't simulate light passing through an object,
but from before (as it replaces ambient).

Maybe a new thing to think about for those POV-Ray core engine
makers... it should be something like focal blur, but only locally.
I think it could be done.

Florian

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