Alain <kua### [at] videotronca> wrote:
> Le 7/24/2012 6:45 PM, Chaanakya a écrit :
> > clipka <ano### [at] anonymousorg> wrote:
> >> Am 24.07.2012 22:02, schrieb Chaanakya:
> >>
> >>> My main issue is the transparency of the solid box when the outer box has an IOR
> >>> of 1.5 - the solid box should not be even slightly transparent!  Is there
> >>> something I'm doing wrong?  Is this a bug?
> >>
> >> The inner box isn't transparent - it just looks like that because the
> >> outer box reflects the pattern of the ground.
> >>
> >> Rotate the ground plane by y*15 (for instance) to see what I mean.
> >
> > Okay.  That makes sense.  But shouldn't the image change if I give it an IOR of
> > -1.5 (instead of 1.5)?  There's no change in the image.
> >
> > Thanks for your help!
> >
> > - Chaanakya
> >
> >
>
> An ior of -1.5! I've tested with negative ior and it gives me a perfect
> mirror. You are beter to use finish{reflection 1}
> This makes sence since the ior is the ratio between the speed of light
> in vacuum and it's speed inside the material.
> Inside_Light_Speed = c/ior.
> A negative ratio means that the direction of the light is reversed.
> With an ior of zero, the result is undefined: Divide by zero.
>
> In your sample, you use reflection{1.0 fresnel} (a prefect mirror! )
> whitch is equivalent to reflection 1. Note the single reflection value.
> As you also have conserve_energy, the 100% reflection means that you
> have 0% transmition. In this case, fresnel have no effect, and the ior
> is useless.
>
> To get a correct result, you should use:
> finish{reflection{0, 1 fresnel}conserve_energy}
> interior{ior Your_ior}
>
>
>
>
>
> Alain

I was told in this thread
(http://news.povray.org/povray.unix/thread/<web.500560817fd5a6c37f523b7e0@news.povray.org>/)
that I should be fine using

pigment { transmit 1 }
finish { reflection { 1 fresnel on } conserve_energy }
interior { ior -1.5 }

as conserve_energy would ensure that the correct amount of light was
transmitted/reflected.

Also, I was told (and the same message is in the docs) that reflection { 1 } is
the same as reflection { 0,1 } because by default it assumes reflection { 0,n }
where n is the float you give it.

Thanks!

- Chaanakya

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