I searched the newsgroups and failed to find if anyone had tried "fiber
optics" by using photons yet and posted results here. Must be people that
have tried it too. I remember doing so, long before the photons feature
existed just to see what would happen. I didn't know any better back then.

Well, it does work now in POV-Ray 3.5, to some extent anyway. This
sphere_sweep tube uses a highly reflective interior_texture and is 100%
clear (rgbf 1) with a ior 1.5 throughout. Ends were CSG differenced away so
they wouldn't reflect there. The red cone points the same as the narrow-beam
spotlight except its tip is where the light source is located. I thought I
would get a more concentrated point of light below the opposite end. This
isn't too far off from expectations anyhow though once considering light
bounce and spreading. At least perhaps not.
--
Farewell,
Bob

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Attachments:
Download 'fiberoptictest1.jpg' (10 KB)

Preview of image 'fiberoptictest1.jpg'

"hughes, b." <omn### [at] charternet> wrote in
news:3de09ecb@news.povray.org 

[...]

interesting, but shouldn't faber-optics have larger IOR ?

-- 
#macro g(U,V)(.4*abs(sin(9*sqrt(pow(x-U,2)+pow(y-V,2))))*pow(1-min(1,(sqrt(
pow(x-U,2)+pow(y-V,2))*.3)),2)+.9)#end#macro p(c)#if(c>1)#local l=mod(c,100
);g(2*div(l,10)-8,2*mod(l,10)-8)*p(div(c,100))#else 1#end#end light_source{
y 2}sphere{z*20 9pigment{function{p(26252423)*p(36455644)*p(66656463)}}}//M

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"Rafal 'Raf256' Maj" <raf### [at] raf256com> wrote in message
news:Xns### [at] 204213191226...
>
> interesting, but shouldn't fiber-optics have larger IOR ?

Only now checked on it and it averages 1.468, according to one source I
found. I had only used 1.5 as a guess of glass-like fiber optic cable. I
wasn't simulating a real one anyway because I knew they don't have truly
reflective interiors, but it seemed the only way for me to be sure and get a
light beam transported through it. I think I'll rerender a more realistic
model and see if photons can be used on that.

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"hughes, b." <omn### [at] charternet> wrote in message
news:3de14cd4@news.povray.org...
> wasn't simulating a real one anyway because I knew they don't have truly
> reflective interiors, but it seemed the only way for me to be sure and get
a
> light beam transported through it. I think I'll rerender a more realistic
> model and see if photons can be used on that.

Didn't work. Refraction alone doesn't seem to guide the light rays well
enough, or simply not in the way intended. Which is, the inner core has a
higher IOR than an outer layer. I won't bother to post the image file, same
as other without the smudge of red light.

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You also have to remember that there's only so much you can bend a real
fiber optic line before the light will escape out.  Mabye your tube is bent
too much in the IOR only test?

Andrew Wilcox

> Didn't work. Refraction alone doesn't seem to guide the light rays well
> enough, or simply not in the way intended. Which is, the inner core has a
> higher IOR than an outer layer. I won't bother to post the image file,
same
> as other without the smudge of red light.
>
>

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You need reflection too to get total internal reflection
Marc


3de24cd0$1@news.povray.org...
> You also have to remember that there's only so much you can bend a real
> fiber optic line before the light will escape out.  Mabye your tube is
bent
> too much in the IOR only test?
>
> Andrew Wilcox
>
> > Didn't work. Refraction alone doesn't seem to guide the light rays well
> > enough, or simply not in the way intended. Which is, the inner core has
a
> > higher IOR than an outer layer. I won't bother to post the image file,
> same
> > as other without the smudge of red light.
> >
> >
>
>

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Marc Jacquier wrote:

> You need reflection too to get total internal reflection
> Marc

Hmm... AFAIK POV handles that automatically for you.

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Gee, you know how long it took me to line that light up with the tube end?
;-)  I wasn't thinking to well when I put it together.

Okay, maybe it will be different if I use a straighter fiber tube then, as
suggested. Guess I better not rescale it all, to hasten that try, or it'd
get flat places in it. I can use the coordinates of the spline of the
sphere_sweep I think.

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