"Hugo" <hua### [at] post3teledk> wrote in message
news:3cdbb971@news.povray.org...
> > Lately, in my modeling of textures, I have been trying to avoid using
> > specular or phong highlight models (in fact, I don't know when the last
> time
> > I used them was) in favour of fresnel reflection, visible light sources
> and
> > surface 'micro-normals'
>
> May sound attractive to use such techniques but the rendertime > down the
> abyss... And doesn't look much different in the end, based on my tries...
> Does fresnel make any difference unless a material has an IOR value?  I
> think, only transparant objects should have IOR... Tell me I'm wrong?
>

In order for fresnel to work (in 3.5) you need an ior.  Read the 3.5 docs on
fresnel for a better understanding and explanation of how it works.  giving
an opaque object an ior value will only affect fresnel reflections since you
can't see through the object anyways.
As for the results looking the same, this is somewhat true for circular
light sources, but not for light sources with other shapes. i.e., ambient
light coming from a square window.
I guess when it comes down to it, I'm a bit of a perfectionist and would
rather try to produce highlights in a more realistic fashion than using
highlight simulation models.

-tgq

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