POV-Ray : Newsgroups : povray.binaries.images : Ambient and cast shadows on metallic textures : Re: Ambient and cast shadows on metallic textures Server Time
28 Jan 2022 04:16:02 EST (-0500)
  Re: Ambient and cast shadows on metallic textures  
From: Alain Martel
Date: 26 Nov 2021 13:02:13
Message: <61a12125$1@news.povray.org>
Le 2021-11-25 à 14:00, Cousin Ricky a écrit :
> On 2021-11-25 1:06 PM (-4), Alain Martel wrote:
>>
>> I came to the conclusion that metallic finishes should have zero ambient
>> through my own experimentation. The metallic textures from the various
>> includes looked just wrong to me.
> 
> Yes, they do look horrible!  My experiments with better metallic
> textures began very soon after I downloaded POV-Ray.
> 
>> I started by commenting out the
>> ambient. I got a massive improvement. Then, I tested with an explicit
>> zero ambient and got the best, most realistic, result.
> 
> As I implied in the OP, I adopted the policy of reducing the ambient in
> proportion to the diffuse, and wrote a macro to do this automatically.
> Since a highly specular surface would have a low diffuse component, this
> naturally leads to very low ambients.  But the ambients in metals.inc
> are *way* out of proportion to the diffuse components!
> 
>> When I first posted about it, I was unaware of Clipka's position on that
>> subject.
>>
>> The metallic finishes from metals.inc have been made to look acceptable
>> in an empty scene against a black background, and that's the only
>> situation where they look somewhat correct.
> 
> Or, how about using a bright sky_sphere along with a large hollow black
> sphere with no_reflection.  Our realistic low-ambient and no-ambient
> metals will show up fine, no need for metals.inc's insane ambients.
> 

Here is my edited versions of metals.inc and golds.inc.
I explicitly set all ambient to zero.


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