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26 Nov 2024 01:52:19 EST (-0500)
  f_noise3d deterministic (Message 1 to 3 of 3)  
From: Neil Kolban
Subject: f_noise3d deterministic
Date: 22 Dec 2004 18:56:29
Message: <41ca09ad@news.povray.org>
Folks,
I wanted to create some irregular spheres ... I created two of these using:

isosurface {
   function { f_sphere(x, y, z, 1)-f_noise3d(x, y, z) }
   contained_by { box { <-2,-2,-2>, <2,2,2> } }
}

this was performed twice.  My problem is that BOTH shapes were identical.  I
had imagined that multiple calls to f_noise3d() would have resulted in
different shapes.

Is this correct?  Any way I can preturb the output of f_noise3d()?

Neil


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From: Warp
Subject: Re: f_noise3d deterministic
Date: 22 Dec 2004 19:25:48
Message: <41ca108c@news.povray.org>
Neil Kolban <kol### [at] kolbancom> wrote:
> this was performed twice.  My problem is that BOTH shapes were identical.  I
> had imagined that multiple calls to f_noise3d() would have resulted in
> different shapes.

  If f_noise3d() would return different values for the exact same parameters
at each call, it would be pretty much useless. It would be just a random
number generator, which would not be usable at all in isosurfaces.

> Is this correct?  Any way I can preturb the output of f_noise3d()?

  Just add a constant to one or more parameters to the function
(ie like f_noise3d(x+10, y+5, z)).

-- 
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -


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From: Neil Kolban
Subject: Re: f_noise3d deterministic
Date: 23 Dec 2004 00:21:51
Message: <41ca55ef$1@news.povray.org>
Thank you my friend.  Just perfect!!

Neil


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