POV-Ray : Newsgroups : povray.binaries.images : Fresnel reflection { 0 } vs. Lambertian : Re: Fresnel reflection { 0 } vs. Lambertian Server Time: 8 Mar 2021 13:18:55 GMT
  Re: Fresnel reflection { 0 } vs. Lambertian  
From: Cousin Ricky
Date: 24 Jun 2020 03:34:56
On 2020-05-06 12:16 PM (-4), William F Pokorny wrote:
> It looks like the parser defaults the finish fresnel to 1.0 if no float 
> specified so you are turning it on in both cases despite not passing a 
> non-zero float - and you have the required ior.
> When the reflection block precedes the finish block's fresnel, the 
> fresnel keyword in the reflection block is turned on. Otherwise it is 
> only on if you specify fresnel in the reflection block yourself.
>  From this, I don't think you are getting fresnel 'reflections' in any 
> case.
> Fresnel is on always though, so it's still doing whatever it does to the 
> other finish components - which I suspect explains the darker result. 
> The idea of the finish level fresnel wasn't much about the reflection 
> block as far as I knew, but about the behavior with respect to other 
> finish elements when you know the (surface) IOR.

This was exactly the situation.  Giving fresnel an argument solved the 
problem.  Thanks!

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