POV-Ray : Newsgroups : povray.unofficial.patches : Sphere-sweep Variations : Re: Sphere-sweep Variations Server Time
2 Sep 2024 12:14:04 EDT (-0400)
  Re: Sphere-sweep Variations  
From: J  Kim
Date: 11 Jan 2000 20:15:26
Message: <387BD5A5.1411B85B@mm.ewha.ac.kr>
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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