hello!

Is it possible to define a plane
which is transparent for light only in one direction and doesnt appear
as object at all  ( it mustn't be seen!) and it mustn't be reflective on
both sides.


like a Glass throuh which i can look only through one direction 
I need it for the following:

I stand at a point and look out through something like a window.
I want to see everything outside the window.
I also want to see if a spotlight from inside illuminates something
outside the window.
But if a spotlight outside the window points at my window, it mustn't
illuminate anything in my room.
Is such a thing possible?
And how?
Thanks for every answer
Matthias

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> 
> [...]
> 
> like a Glass throuh which i can look only through one direction
> I need it for the following:
> 
> I stand at a point and look out through something like a window.
> I want to see everything outside the window.
> I also want to see if a spotlight from inside illuminates something
> outside the window.
> But if a spotlight outside the window points at my window, it mustn't
> illuminate anything in my room.
> Is such a thing possible?
> And how?

You could try megapov's 'interior_texture' feature

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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On Fri, 18 May 2001 10:50:32 +0200, Christoph Hormann wrote:
>You could try megapov's 'interior_texture' feature

Or megapov's light groups, or projected_through.  For this, projected_through
would probably be the most elegant solution.

-- 
#macro R(L P)sphere{L F}cylinder{L P F}#end#macro P(V)merge{R(z+a z)R(-z a-z)R(a
-z-z-z a+z)torus{1F clipped_by{plane{a 0}}}translate V}#end#macro Z(a F T)merge{
P(z+a)P(z-a)R(-z-z-x a)pigment{rgbf 1}hollow interior{media{emission 3-T}}}#end 
Z(-x-x.2x)camera{location z*-10rotate x*90normal{bumps.02scale.05}}

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> 
> hello!
> 
> Is it possible to define a plane
> which is transparent for light only in one direction and doesnt appear
> as object at all  ( it mustn't be seen!) and it mustn't be reflective on
> both sides.

Just as a remark: there is no glass in reality that you can only
look through in one direction. It all depends on the lighting
on either side of the glass...

Markus

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"Markus Becker" <bec### [at] aicossde> wrote in message
news:3B261608.4B31A78F@aicoss.de...

> >
> > hello!
> >
> > Is it possible to define a plane
> > which is transparent for light only in one direction and doesnt appear
> > as object at all  ( it mustn't be seen!) and it mustn't be reflective on
> > both sides.
>
> Just as a remark: there is no glass in reality that you can only
> look through in one direction. It all depends on the lighting
> on either side of the glass...
>
> Markus

Actually, this type of object does exist in reality.  It is usually called a
one way mirror.  (Found in stores with offices on the side that can see out
into the store without the shoppers knowing they can be seen)  It works by
using a flat (not shiny) reflective coating on one side of a piece of glass.
This is the best description I can think of off the top of my head.

N Shomber

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N Shomber wrote:
> 
> > Just as a remark: there is no glass in reality that you can only
> > look through in one direction. It all depends on the lighting
> > on either side of the glass...

> Actually, this type of object does exist in reality.  It is usually called a

No, it does not. See below.

> one way mirror.  (Found in stores with offices on the side that can see out
> into the store without the shoppers knowing they can be seen)  It works by
> using a flat (not shiny) reflective coating on one side of a piece of glass.

What you are describing here is a normal mirror.
It only works, when the "office" behind the mirror is dark
compared to the store side of the mirror and the mirror is only half
reflecting.

Markus

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