"Chaanakya" <nomail@nomail> wrote:
> clipka <ano### [at] anonymousorg> wrote:
> > Am 17.07.2012 18:09, schrieb Chaanakya:
> >
> > > 4) I have found that if I only specify the IOR, conserve_energy, and fresnel
> > > (with no pigment { transmit N.N } block), the object looks black.  This is the
> > > one thing I don't understand.
> >
> > Specify "transmit 1.0"; with conserve_energy, AFAIK you should be fine.
> >
> > POV-Ray doesn't automatically do that for you because some people
> > /might/ want to model non-transparent reflective materials, you know ;-)
> >
> > You might argue that specifying an ior should automatically imply
> > transparency, but this is not so: Real life opaque surfaces (or rather,
> > surfaces of opaque materials) obey fresnel's law as well, so for best
> > realism you need to use "fresnel on" and specify an ior for those as
> > well, and even top it off with "conserve_energy" to modulate the diffuse
> > reflection accordingly.
> >
> > (All non-metallic "opaque" materials are actually transparent with very
> > strong absorption and/or scattering effects; it would be too complex to
> > model them as such though, hence the shortcut with a "surface color".)
> >
> > If you have a scene with plenty of transparent stuff, you might want to
> > specify "default { pigment { rgbt 1 } }" at the beginning of your scene
> > file to save you a bit of typing.
>
> Something's not working correctly - if I make a cube with an IOR of 1.5
> (essentially a glass cube), I don't see a reflection.  There should be a
> reflection at some point of the cube, but I don't see that.  I should see a
> difference with conserve_energy toggled, but I'm not seeing that.  I think
> there's something else that needs to be done, but I'm not sure what.
>
> - Chaanakya

Also, the example given in this thread should work with this method and it
doesn't:
http://news.povray.org/povray.beta-test/message/%3Cweb.500469a1adf6cd217f523b7e0%40news.povray.org%3E/#%3Cweb.500469a1a
df6cd217f523b7e0%40news.povray.org%3E

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