In article <4224eba5$1@news.povray.org>, "Eli" <eli### [at] jehoelnet> wrote:

> Taken from http://www.dotcsw.com/doc/options.html: "While the Perlin 
> algorithm is widely used and efficient to generate, it suffers from 
> directional artifacts and always returns 0.5 when passed whole numbers."
> 
> So that explains the rectangular artifacts we have been encountering! 

Is this in response to my Lewis noise patch? It could as well be a 
separate message that got sent as a reply by accident...

There is an updated version of Perlin noise which makes the lattice 
artifacts less obvious (though it doesn't solve the problem of always 
equalling 0.5 at regular intervals), as well as giving an overall 
speedup and improvement in overall evenness of the noise. It doesn't 
entirely eliminate the problem, though. Also, the POV team has been 
aware of this for some time...probably the only reason it's not in 3.6 
is lack of time. Lewis noise is an entirely different algorithm.

-- 
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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