Dear all,
   I understand there is a sphere-sweeping function(sphere-sweep-spline)
in the superpatchPOV. Would it be possible to start from something else
other than a
sphere? For example, sweeping with some egg-like primitives, or
triangle-shaped sphere-variants, or torus along a predefined curve/path.
If I could possibly choose a torus as a starting primitive for the
sweeping, that would generate a hollow tube, or pipe.
 I would like to know whether this is some sort of built-in function by
changing some options  in the patch, or somewhat involving task like
writing lines-and-lines of programming.

Thanks in advance,
  Jong

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J Kim <sjy### [at] shinbirocom> writes:
>
>    I understand there is a sphere-sweeping function(sphere-sweep-spline)
> in the superpatchPOV. Would it be possible to start from something else
> other than a
> sphere? For example, sweeping with some egg-like primitives, or
> triangle-shaped sphere-variants, or torus along a predefined curve/path.
> If I could possibly choose a torus as a starting primitive for the
> sweeping, that would generate a hollow tube, or pipe.
>  I would like to know whether this is some sort of built-in function by
> changing some options  in the patch, or somewhat involving task like
> writing lines-and-lines of programming.

As far as I know, it the latter case is true. The implementation of the 
sphere_sweep object is tied with the shape of a sphere. In fact, there is 
no object swept internally. The shape of the sphere_sweep has been 
calculated "by hand" up to parameterization. By this, the intersection of 
the ray and the sphere_sweep can be determined efficently.

Perhaps you should have a look at the original page of the creator of this
patch:
http://www.informatik.uni-bremen.de/~vader/pss/pss.html

When you want to sweep other objects, I suggest that you create a bunch
of objects. This can be done either directly or with one of the various 
macros mentioned by others.

On the other hand, substracting two sphere_sweeps with different radii
may be close to your desired torus_sweep.

Happy tracing
Thomas

-- 
http://thomas.willhalm.de/ (includes pgp key)

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Thomas Willhalm wrote:

> When you want to sweep other objects, I suggest that you create a bunch
> of objects. This can be done either directly or with one of the various
> macros mentioned by others.

This is an interesting macro that might do the job -
http://members.xoom.com/dvarrazzo/epov.htm

-- 
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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Dear Thomas,

 I really appreciate your help.

Jong.

Thomas Willhalm wrote:

> J Kim <sjy### [at] shinbirocom> writes:
> >
> >    I understand there is a sphere-sweeping function(sphere-sweep-spline)
> > in the superpatchPOV. Would it be possible to start from something else
> > other than a
> > sphere? For example, sweeping with some egg-like primitives, or
> > triangle-shaped sphere-variants, or torus along a predefined curve/path.
> > If I could possibly choose a torus as a starting primitive for the
> > sweeping, that would generate a hollow tube, or pipe.
> >  I would like to know whether this is some sort of built-in function by
> > changing some options  in the patch, or somewhat involving task like
> > writing lines-and-lines of programming.
>
> As far as I know, it the latter case is true. The implementation of the
> sphere_sweep object is tied with the shape of a sphere. In fact, there is
> no object swept internally. The shape of the sphere_sweep has been
> calculated "by hand" up to parameterization. By this, the intersection of
> the ray and the sphere_sweep can be determined efficently.
>
> Perhaps you should have a look at the original page of the creator of this
> patch:
> http://www.informatik.uni-bremen.de/~vader/pss/pss.html
>
> When you want to sweep other objects, I suggest that you create a bunch
> of objects. This can be done either directly or with one of the various
> macros mentioned by others.
>
> On the other hand, substracting two sphere_sweeps with different radii
> may be close to your desired torus_sweep.
>
> Happy tracing
> Thomas
>
> --
> http://thomas.willhalm.de/ (includes pgp key)

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Dear Ken,

 I really thank you for your help.

Jong

Ken wrote:

> Thomas Willhalm wrote:
>
> > When you want to sweep other objects, I suggest that you create a bunch
> > of objects. This can be done either directly or with one of the various
> > macros mentioned by others.
>
> This is an interesting macro that might do the job -
> http://members.xoom.com/dvarrazzo/epov.htm
>
> --
> 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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