Hi,

Is it possible to make a noise3d isosurface on a sphere_sweep ?

Thanks in advance,

JT

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On Mon, 07 Apr 2003 18:54:11 +0200, J Tellings <jte### [at] chellonl> wrote:
> Is it possible to make a noise3d isosurface on a sphere_sweep ?

No doubts it is possible with linear path using smart script. But other paths
need very complex math which is hard to code within function. I did patch with
polynomiar solver support in function engine for such purposes but never made
practical test. Once I tried but couldn't finish.

ABX

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Wasn't it J Tellings who wrote:
>Hi,
>
>Is it possible to make a noise3d isosurface on a sphere_sweep ?

It's possible to approximate some sphere_sweeps with isosurfaces, using
the spline functions as parameters to the isosurface function.

Observe the fourth and fifth examples on 
<http://www.econym.demon.co.uk/isotut/more.htm>
and imagine also using a second spline function to specify the square of
the radius instead of using the fixed value (0.05 in the example)
(assuming you do want to vary the radius in your particular example).

You have to use a second spline, because spline functions only have
three co-ordinates whereas the splines used within sphere_sweeps control
an <x,y,z> position plus a radius.

Those examples are actually "hoop sweeps" rather than a sphere_sweeps,
but if your particular sphere_sweep doesn't twist too much, such a hoop
sweep might well look reasonable. 

Once you've got it as an isosurface, you can add f_noise3d() to it.

-- 
Mike Williams
Gentleman of Leisure

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J Tellings <jte### [at] chellonl> wrote:
> Is it possible to make a noise3d isosurface on a sphere_sweep ?

  Isosurfaces do not have magical properties. An isosurface is a primitive
like any other primitive in povray, with the exact same limitations.
  You could ask if you can make a torus on a sphere_sweep and the question
would make the same sense.

  "Can I make an isosurface which follows a spline, in a similar way a
sphere_sweep does?" would make more sense, but it's a difficult question.
Someone with more experience with splines+isosurfaces may answer it better
than me.

-- 
#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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