Alain <aze### [at] qwertyorg> wrote:

> >
> >
> > Alain<azerty [at] qwertyorg>  wrote:

> >>> Alain wrote:

> >>>>> Hi All,
> >>>>>
> >>>>> I'm new to POV-Ray and I'm trying to create a "bent cylinder" or a thick arc
> >>>>> that passes through 5 points. I think that a quadratic spline might do it, but
> >>>>> I'm not sure exactly how to go about it... The five points I would like it to
go
> >>>>> through are the following and I would like are:
> >>> [snip]
> >>>>
> >>>> You can use the sphere_sweep primitive. Try the b_spline and
> >>>> cubic_spline. Be warned that those splines uses the first and last
> >>>> points as control points and that the actual ubject don't reatch those.
> >>>>
> >>> [snip]
> >>>
> >>> I just wrote something similar and found a sphere_sweep with a cubic_spline
> >>> works well by making the first point equal to the second, and the next-to-last
> >>> equal to the last.  In my case I was only connecting (for example) two corner
> >>> points c1 and c2 through a side point s5 in two dimensions.  The radius of the
> >>> "bent cylinder" is r.
> >>>
> > [snip]
> >>
> >> Up until the 2 last 3.7 betas, the sphere_sweep had some bugs causing
> >> all sort of artefacts.
> >> Also, if you have a control point coincident with an end point, it can
> >> missbehave. It can work some times, and have some strange effects at others.
> >>
> >>
> >>
> >> Alain
> >
> >
> > Thanks for your help!
> >
> > I've got it working now to some extent based on the splinefollow example, I can
> > get the cylinder to start at one point (purple top), trace through the others in
> > order but not have it end at the point I would like (purple bottom). It seems to
> > go through no matter what I do...! Could it be a problem with the while? the
> > file is pasted below.
> >
> > Thanks in advance,
> >
> > Jack
> >
>
> Played with that a bit and found that removing the following point seems
> to solve the overshot problem:
> 06, < 15.646700,9.031800,10.928100>,
>
>
> Alain

Thanks Alain,

That certainly solves the overshoot... but now it doesn't quite make it to the
final ball?
I guess I could try and deal with this by increasing the ball size, but it would
be great if it could actually make it to the ball!

Jack

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