Hugo Elias has an interesting method to create spherical planetoids:

  http://freespace.virgin.net/hugo.elias/models/m_landsp.htm

I tried to implement his method by recursively splitting an object (started
as a sphere) in random halves, and scaling one half slightly larger than the
other, then doing it over and over again. The method seems to work at low
iterations (<15), but when I went ahead and tried, say, 100 iterations, it
was taking *forever* to parse, and never did start rendering, my computer
locked on me, probably not enough memory. I'm interesting in implementing
this technique in POV-Ray, does anyone have any ideas to use less memory and
speed it up? I have included my source.

Or, does anyone have a better method to create planetoids such as these?

--
Paul Vanukoff
van### [at] primenetcom


// source follows //


#include "colors.inc"

#declare s1=seed(95937);

#declare Planetary=
sphere
{
    < 0, 0, 0> 1
}

#declare K=0;
#while (K<15)        // number of iterations

#declare rotX=360*rand(s1);
#declare rotY=360*rand(s1);
#declare rotZ=360*rand(s1);

#declare HalfOne=
intersection
{
    box
    {
        <-1.2,0,-1.2>,<1.2,1.2,1.2>
        rotate <rotX, rotY, rotZ>
    }

    object
    {
        Planetary
    }
    scale 1.001
}

#declare HalfTwo=
intersection
{
    box
    {
        <-1.2,-1.2,-1.2>,<1.2,0,1.2>
        rotate <rotX, rotY, rotZ>
    }

    object
    {
        Planetary
    }
    scale 0.999
}

#declare Planetary=
merge
{
    object
    {
        HalfOne
    }

    object
    {
        HalfTwo
    }
}

#declare K=K+1;
#end

camera
{
    location < 0, 0, -3>
    look_at < 0, 0, 0>
}

light_source
{
    < 0, 9, -3>
    color White
}

light_source
{
    < 0, -9, 0>
    color White/3
}

object
{
    Planetary

    pigment
    {
        color White
    }
}

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Paul Vanukoff wrote:

> Or, does anyone have a better method to create planetoids such as these?

John Beale's OrbCyl progam comes to mind -
http://shell3.ba.best.com/~beale/gforge/

-- 
Wishing you Seasons Greetings, A Merry Christmas, Happy New Millennium !
Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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You can do it with a hf used as a isosurface pigment mapped onto a sphere.

I'll look it up and send  an example to you.

Mick

--
*************************************************************
Have a merry Christmas and a happy new year.
 Please visit my web site at:-
       http://www.minda.swinternet.co.uk/index.htm

*************************************************************
Paul Vanukoff <van### [at] primenetcom> wrote in message
news:386252b0@news.povray.org...
>
> Hugo Elias has an interesting method to create spherical planetoids:
>
>   http://freespace.virgin.net/hugo.elias/models/m_landsp.htm
>
> I tried to implement his method by recursively splitting an object
(started
> as a sphere) in random halves, and scaling one half slightly larger than
the
> other, then doing it over and over again. The method seems to work at low
> iterations (<15), but when I went ahead and tried, say, 100 iterations, it
> was taking *forever* to parse, and never did start rendering, my computer
> locked on me, probably not enough memory. I'm interesting in implementing
> this technique in POV-Ray, does anyone have any ideas to use less memory
and
> speed it up? I have included my source.
>
> Or, does anyone have a better method to create planetoids such as these?
>
> --
> Paul Vanukoff
> van### [at] primenetcom
>
>
> // source follows //
>
>
> #include "colors.inc"
>
> #declare s1=seed(95937);
>
> #declare Planetary=
> sphere
> {
>     < 0, 0, 0> 1
> }
>
> #declare K=0;
> #while (K<15)        // number of iterations
>
> #declare rotX=360*rand(s1);
> #declare rotY=360*rand(s1);
> #declare rotZ=360*rand(s1);
>
> #declare HalfOne=
> intersection
> {
>     box
>     {
>         <-1.2,0,-1.2>,<1.2,1.2,1.2>
>         rotate <rotX, rotY, rotZ>
>     }
>
>     object
>     {
>         Planetary
>     }
>     scale 1.001
> }
>
> #declare HalfTwo=
> intersection
> {
>     box
>     {
>         <-1.2,-1.2,-1.2>,<1.2,0,1.2>
>         rotate <rotX, rotY, rotZ>
>     }
>
>     object
>     {
>         Planetary
>     }
>     scale 0.999
> }
>
> #declare Planetary=
> merge
> {
>     object
>     {
>         HalfOne
>     }
>
>     object
>     {
>         HalfTwo
>     }
> }
>
> #declare K=K+1;
> #end
>
> camera
> {
>     location < 0, 0, -3>
>     look_at < 0, 0, 0>
> }
>
> light_source
> {
>     < 0, 9, -3>
>     color White
> }
>
> light_source
> {
>     < 0, -9, 0>
>     color White/3
> }
>
> object
> {
>     Planetary
>
>     pigment
>     {
>         color White
>     }
> }
>
>

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Ken wrote in message <38625546.33CE31F7@pacbell.net>...

>John Beale's OrbCyl progam comes to mind -
>http://shell3.ba.best.com/~beale/gforge/

Oh, that's really neat. Thanks!

--
Paul Vanukoff
van### [at] primenetcom

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I made a macro to do this quite a while ago, but it is pretty much 
useless, because the render time at a good level of recursion is 
huge(because of the deeply nested difference operations). However, it 
shouldn't be too hard to make a macro which outputs a mesh, this 
wouldn't have that problem.
Of course, then you have the usual problems with meshes.(faceting, high 
memory usage, etc.

-- 
Chris Huff
e-mail: chr### [at] yahoocom
Web page: http://chrishuff.dhs.org/

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I've never been good at effecient scenes, but this sounds like a cool idea and
I'll have to try it...

--
Homepage: http://www.faricy.net/~davidf/
___     ______________________________
 | \     |_       <dav### [at] faricynet>
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