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Here's a simple enough question...
Is it possible for a transparent substance to be non-reflective? Or are all
transparent substances inherantly reflective to a certain degree?
Just wondering...
Andrew.
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> Is it possible for a transparent substance to be non-reflective? Or
are all
> transparent substances inherantly reflective to a certain degree?
I doubt such a substance exists. If something was truly non-reflective,
it would be perfectly invisible, unless it was absorbing light against a
background or was emitting light itself. I can't think of anything that
is perfectly invisible like that, though I should think that some gases
come close, but perhaps only on account of their low density under
Earthly conditions.
And there would also be the problem of total internal reflection.
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Andrew Coppin wrote:
> Here's a simple enough question...
>
> Is it possible for a transparent substance to be non-reflective? Or are
> all transparent substances inherantly reflective to a certain degree?
>
> Just wondering...
> Andrew.
Certainly within the realm of the visible. You don't see your reflection in
the air do you?
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Hmm... gases don't *appear* reflective... but does a gas have a surface???
Andrew.
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On Thu, 8 May 2003 08:32:30 +0100, "Andrew Coppin" <orp### [at] btinternet com> wrote:
> Hmm... gases don't *appear* reflective... but does a gas have a surface???
Between your eye and gas ?
ABX
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> Is it possible for a transparent substance to be non-reflective? Or are all
> transparent substances inherantly reflective to a certain degree?
I always assumed that if light travels into a denser medium (with higher
ior), some of it will be reflected, because "the light does not want to
go through the trouble of traveling through a dense medium". On the other
hand there will be no reflection (except total reflection), when light
travels into a coarser (?English? less dense?) medium.
To make this post on-topic: That's why I always switch reflection off for
the interior_texture of glass and water materials.
Now all of that was assumptions. Can anybody who knows better please
- tell us if that was right?
- give us a formula for the correct reflection value between different
ior's (assuming it does not depend on anything else)?
--
merge{#local i=-11;#while(i<11)#local
i=i+.1;sphere{<i*(i*i*(.05-i*i*(4e-7*i*i+3e-4))-3)10*sin(i)30>.5}#end
pigment{rgbt 1}interior{media{emission x}}hollow}// Mark Weyer
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OK, well, a lump of shashed up ice doesn't look reflective at all... but
take a bit and polish it to give it a nice smooth surface and you find that
it actually IS reflective. Was thinking, if you have a layer of gas, it's
surface probably isn't smooth, which might explain why it doesn't look
reflective.
If that makes sense.
Andrew.
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On Thu, 8 May 2003 08:48:09 +0100, "Andrew Coppin" <orp### [at] btinternetcom> wrote:
> OK, well, a lump of shashed up ice doesn't look reflective at all...
But I think it is reflective, just with a lot of blur :-)
> Was thinking, if you have a layer of gas, it's
> surface probably isn't smooth, which might explain why it doesn't look
> reflective.
On desert you can see images in the air. You know how ?
http://www.islandnet.com/~see/weather/graphics/photos/supmirag.gif
ABX
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Andrew <ast### [at] hotmailcom> wrote:
> If something was truly non-reflective,
> it would be perfectly invisible
A transparent object which refracts light is never invisible.
--
plane{-x+y,-1pigment{bozo color_map{[0rgb x][1rgb x+y]}turbulence 1}}
sphere{0,2pigment{rgbt 1}interior{media{emission 1density{spherical
density_map{[0rgb 0][.5rgb<1,.5>][1rgb 1]}turbulence.9}}}scale
<1,1,3>hollow}text{ttf"timrom""Warp".1,0translate<-1,-.1,2>}// - Warp -
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Andrew Coppin wrote:
>
> Here's a simple enough question...
>
> Is it possible for a transparent substance to be non-reflective? Or are all
> transparent substances inherantly reflective to a certain degree?
Reflection is an inherent effect on all interfaces between materials of
different optical density (i.e. ior, speed of light in the material)
The amount of reflection depending on the incident angle and the materials
can be calculated with the fresnel equations. This works for both a
transit from less dense to more dense medium as well as the other way
round. More information can be found in the links from:
http://www-public.tu-bs.de:8080/~y0013390/pov/water/water_app1.html#reflect
Christoph
--
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 28 Feb. 2003 _____./\/^>_*_<^\/\.______
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