POV-Ray : Newsgroups : povray.general : A good blurred reflection with bumps : Re: A good blurred reflection with bumps Server Time
3 Aug 2024 22:14:02 EDT (-0400)
  Re: A good blurred reflection with bumps  
From: Christopher James Huff
Date: 7 Jan 2004 09:14:54
Message: <cjameshuff-38C74C.09145807012004@netplex.aussie.org>
In article <vcs### [at] tritonimagicode>,
 Christoph Hormann <chr### [at] gmxde> wrote:

> No.  The problem with blurred reflection is not a resolution problem, if 
> it was you could render the scene at larger size (without aa) and get a 
> nice image.  Blurred reflections is about blur, i.e. averaging of color 
> values.  This is not unrealistic at all, in real life the averaging is 
> mostly matter of interference, diffraction, etc.

A blurred reflection is the result of small surface features causing a 
reflections from nearby points on the surface to go in different 
directions. The area of a receptor in the eye covers an area of the 
surface, with many reflections from microfacets. And this is exactly 
what antialiasing is intended to do...it samples the area covered by a 
pixel, rather than a single point. Micronormals combined with very high 
supersampling would be the most accurate method. However, supersampling 
the surface geometry is usually a waste of time, as well as the diffuse 
and highlight aspects of the texture, so a method that samples only the 
reflections would be quite a bit more efficient.

There is a blurring effect in the eye and brain, which is why things 
like dithering work, but it results in a grainy appearance even when 
individual features can not be perceived. You can tell sand, salt, and 
sugar are granular even when you can't see individual grains. Objects 
that appear to have a smooth blurryness to their reflections have 
surface features too small for this to come into play.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: <chr### [at] tagpovrayorg>
http://tag.povray.org/


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