POV-Ray : Newsgroups : povray.general : 2D function to 3D tube : Re: 2D function to 3D tube Server Time
4 Feb 2023 01:04:30 EST (-0500)
  Re: 2D function to 3D tube  
From: Droj
Date: 6 Jan 2023 12:30:00
Message: <web.63b85996560d616820e7fc03b2af915@news.povray.org>
"Droj" <803### [at] drojde> wrote:
> "Droj" <803### [at] drojde> wrote:
> > I was interested to see how can a 2D curve get a more interesting life in a 3D
> > world.
> > And I found a promising approach in the Internet on B. Frassek's website
> > https://www.frassek.org (sorry, the site is in German but an automatic
> > translation is available). Look for 'function graph as pipe/tube'.
> > The steps are outlined here:
> >
> >  - take the parametric function of a circle as cross section for the tube
> >  - determin the gradient of the 2D curve you want to use (derivatives must
> > exist)
> >  - let the center of the cross section travel along the 2D curve (e.g. like
> > insulation on a copper wire)
> >
> > Alas, that's it.
> >
> > So I started to adapt all the functions to Povray. I am aware that using atan2
> > is an unexplicable mystery but what the heck.
> >
> > The result was sort of sobering as the tube was flatend in some parts and bulgy
> > in others.
> > I upload the POV-Script I generated to show the problem.
> >
> > Any suggestions (if there are any) on how to get a perfectly round tube are
> > welcome but I need the parametric approach as I want to use the .inc/.obj output
> > for more things to come.
> Hi to all,
> I guess this subject is rather exhausted.
> Don't take me wrong I have the highest esteem for those who developed the
> meshmaker macros and I am not happy to be the igorant, bloody user finding the
> fly in the ointment - provided there is any as there is no proof.
> Be assured the meshmaker macros work flawlessly with a heap of parametric
> functions I tested.
> My thanks to all who took part in this fruitful discussion and for actively
> sharing their knowledge.
> For the time being I will use Bill's solution to test some more curves and
> produce interesting tubes including the .obj/.inc files.
> And finally here's something I made in a jiffy - no great artistic work I admit.

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