POV-Ray : Newsgroups : povray.general : Glass for v3.8 finish features : Re: Glass for v3.8 finish features Server Time
8 Aug 2022 22:06:04 EDT (-0400)
  Re: Glass for v3.8 finish features  
From: Alain Martel
Date: 3 Aug 2022 13:00:06
Message: <62eaa996$1@news.povray.org>
Le 2022-08-02 à 11:29, Chris R a écrit :
> Whenever I create a scene that contains objects made of glass, I spend a lot of
> time tweaking the various pigment, finish, and interior parameters of the
> material to try and get something that looks realistic.  Sometimes I start with
> what I can find in glass.inc, but it doesn't appear to have been updated since
> v3.5.
> 
> Has anyone worked on something similar to RC3Metal for glass that takes
> advantage of all of the new finish features in later versions?  It might be
> something I'd be willing to explore, but I don't have a great grasp on how all
> of combinations, including fresnel interact, so it's going to be hit and miss.
> 
> Thanks,
> 
> -- Chris R.
> 
> 

Normally, for a transparent object having an IOR, you use reflection{1 
fresnel} to control the reflectivity. There is usually no need to use 
another value here.
Fresnel reflection depends entirely on the ratio between the ior on each 
sides of the surface and the angle of incidence. A ratio of 1 mean NO 
reflection. A standalone object without an interior defining an ior 
different from 1 will also show no fresnel reflection.

When the fresnel keyword is present, it always default to ON.
falloff and exponent should be left to their default values. Don't use 
those.
Do not use metallic.

Then, you should also use the fresnel option for the highlights. Need 
the latest version. IIRC, it was not implemented in version 3.7, but is 
supported in the latest V1.8 beta.
Examples : specular 0.7 fresnel roughness 0.001, phong 0.7 fresnel 
phong_size 500

Also, you should use transmit 1 or filter 1 as your pigment.
If you want the object to be coloured, use fading in the interior 
statement :
interior{ior 1.5 fade_color rgb<1, 0.6, 0.6> fade_distance 1 fade_power 
1001}// A pink object.
Adjust fade_distance for the dimension and scale of your object. It's 
easily the most important parameter when using fading colours in an 
interior.

ALWAYS use conserve_energy.

Sample glass :
texture{
	pigment{rgbt 1}
	finish{specular 1 roughness 0.001 fresnel
		ambient 0 diffuse 0
		reflection{ 1 fresnel }
		conserve_energy
	}
}
interior{ ior 1.5 //typical glass IOR
	fade_color rgb<0.9, 1, 0.9>//slightly greenish
	fade_distance 2 // Adjust to the size and scale of the object
	fade_power 1001}


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