Imagine that you want to obtain an object, located in front of a mirror,
gives back a different image. Easy!  you will say, the new feateure
"no_reflection" should perfect for this....

In this image, we see a red sphere located in front of a mirror, marked with
no_reflection
http://usuarios.lycos.es/game2413/galeria/untitled1.jpg
Problem 1, the shade is visible through the mirror.

Good, you will say, I can fix it with "no_shadow"
http://usuarios.lycos.es/game2413/galeria/untitled2.jpg
Problem 2, the shade has disappeared.... but to this side of the mirror,
too! The absence of shades prevents to locate correctly to the sphere in the
image

Try to think about another thing...  we left the sphere, marked with
"no_reflection" and locate a box, only visible across the mirror, marked
with "no_image"

Problem 3, well, the shade of the box projects in the "real" side... but
over the sphere too.
http://usuarios.lycos.es/game2413/galeria/untitled3.jpg

we proved to clear box's shadows...
http://usuarios.lycos.es/game2413/galeria/untitled4.jpg
aha, now we have a box that projects round shades...

do anybody have an idea?

Bruno Gimeno
solo tendreis mi ordenador
cuando me arranqueis el teclado
de mis frios dedos muertos

PS using photohop is cheat!
http://usuarios.lycos.es/game2413/galeria/untitled5.jpg

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Bruno Gimeno wrote:
> 
> Imagine that you want to obtain an object, located in front of a mirror,
> gives back a different image. Easy!  you will say, the new feateure
> "no_reflection" should perfect for this....
> 
> In this image, we see a red sphere located in front of a mirror, marked with
> no_reflection
> http://usuarios.lycos.es/game2413/galeria/untitled1.jpg
> Problem 1, the shade is visible through the mirror.
> 
> [...]

I think this is a design feature and can't be changed easily, but i can't
say for sure since i don't know how exactly 'no_reflection' etc. are
implemented.  I suppose you can solve it in your case by having two
instances of the floor object, one with diffuse finish and
'no_reflection', one without and 'no_image'.  

Christoph

-- 
POV-Ray tutorials, IsoWood include,                 
TransSkin and more: http://www.tu-bs.de/~y0013390/  
Last updated 05 May. 2002 _____./\/^>_*_<^\/\.______

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imagine a second mirror in your scene, that's supposed to show both ojects ...
how should it deal with the shadows ?

now, wouldn't this end up with a list, that for every object and every declared
finish describes how to deal appearance ? ... probably, so this problem comes
from the design ...

I was never a fan of using such faking effects like no_* ... and it seems I'll
never be ...

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Bruno Gimeno wrote:
> do anybody have an idea?
> 

Are you suggesting that instead of:
 no_image
 no_reflection
 no_shadow

Pov would need something like:
 no_image
 no_reflection
 no_real_shadow
 no_reflected_shadow

?

Would there be any interest for such things ?

What about also then about highlight effect ?
Shouldn't then Pov need something like:
 no_image
 no_reflection
 no_real_highlight
 no_real_shadow
 no_reflected_highlight
 no_reflected_shadow

Moreover, what about refracted rays :
 no_refraction
 no_refracted_highlight
 no_refracted_shadow 

And lastly, what about transmited rays:
 no_transmition
 no_transmited_highlight
 no_transmited_shadow

Wouldn't then using a paint program instead of a raytracer be simpler ?
Or does someone really see a utility for that level of detail ?
-- 
Non Sine Numine
http://grimbert.cjb.net/
Etiquette is for those with no breeding;
fashion for those with no taste.

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Bruno Gimeno wrote:
>
> PS using photohop is cheat!

Cheating is in the eye of the loser :^)


_____________
Kari Kivisalo

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I concede now that shadows are not affected by no_reflection and/or no_image
themselves when involving mirrors. Maybe you will too.  ;-)

Please see my reply to TinCanMan's lightgroup message, recently posted to
povray.beta-test.

bob h

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Bruno Gimeno wrote:
> 
> Imagine that you want to obtain an object, located in front of a mirror,
> gives back a different image. Easy!  you will say, the new feateure
> "no_reflection" should perfect for this....
> [...snip...]
>do anybody have an idea?


Not so easy, as your full message points out. But here's something
you could do, although you would probably need to experiment a bit
to get it to look right.

1.) Create a scene with the cut box alone where the sphere is. Use a
   camera looking back at it from the other side of the mirror, removing
   the back wall, mirror and sphere. Render this.

2.) Use the results of 1.) as an image map on the "mirror" instead of
   "real" reflection. This is where the a lot of experimentation is
   needed: you must get the reverse camera's angle right to look 
   like a believable reflection (not perfectly right, of course:
   this is a surreal scene you describe, so to some degree we expect 
   it to look "unreal") 

3.) Add back in the rest of the scene and remove the cut box. 

This should make even a "no-post processing" purists happy, since
the map comes from POV itself even if it is from a separate step.

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