POV-Ray : Newsgroups : povray.newusers : Normal bumpiness : Re: Normal bumpiness Server Time
2 Nov 2024 17:20:14 EDT (-0400)
  Re: Normal bumpiness  
From: Christopher James Huff
Date: 18 Nov 2003 14:16:05
Message: <cjameshuff-9FEC18.14125118112003@netplex.aussie.org>
In article <3fba4cd2$1@news.povray.org>,
 "Tim Nikias v2.0" <tim.nikias (@) nolights.de> wrote:

> > I just discovered that each time I render the scene, the bumpiness stay
> the
> > same. Isn't a random function?

Pseudo-random, and reproduceable.


> Povray makes use of pseudo-random streams, but for normals, it uses the
> inbuilt patterns, and they're not random at all. And even if you use the
> rand()-stream to actually randomize the "location" of the pattern, then it
> will stay the same as long as the seed isn't changed. I'm not too sure about
> different platforms though, some Guru needs to answer that.

The noise patterns will be identical on any platform. The only things 
that vary from render to render are jitter and crand, which is one 
reason they are discouraged in animations.

-- 
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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