I've got the following problem: when i create a sphere sweep like this

sphere_sweep {
    linear_spline
    4,
    <0, height, 0>, 0.05,
    <0, height+1, 0>, 0.05,
    <0, height+2, 0>, 0.05,
    <0, height+3, 0>, 0.05
}

the produced body looks as it should be. But when i use b_spline (or
cubic_spline) it is cut off in y-direction, so that effectively it looks
like:

sphere_sweep {
    linear_spline
    4,
    <0, height+2, 0>, 0.05,
    <0, height+2, 0>, 0.05,
    <0, height+2, 0>, 0.05,
    <0, height+3, 0>, 0.05
}

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Ed,
I am a newbie here too but my understanding is that with the b_spline, there
are points before and after the ones that you want "visible" that direct the
shapes entry and exit from the scene.

Have a look at the following web page:
http://www.cse.unsw.edu.au/~lambert/splines/Bspline.html

You will notice that points '0' and '3' don't "show" in the curve but have a
strong effect on how the curve starts and ends.

Neil

"Ed Mann" <nomail@nomail> wrote in message
news:web.41c8cdaaa10ca6393028a1b20@news.povray.org...
> I've got the following problem: when i create a sphere sweep like this
>
> sphere_sweep {
>     linear_spline
>     4,
>     <0, height, 0>, 0.05,
>     <0, height+1, 0>, 0.05,
>     <0, height+2, 0>, 0.05,
>     <0, height+3, 0>, 0.05
> }
>
> the produced body looks as it should be. But when i use b_spline (or
> cubic_spline) it is cut off in y-direction, so that effectively it looks
> like:
>
> sphere_sweep {
>     linear_spline
>     4,
>     <0, height+2, 0>, 0.05,
>     <0, height+2, 0>, 0.05,
>     <0, height+2, 0>, 0.05,
>     <0, height+3, 0>, 0.05
> }
>
>
>
>

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"Neil Kolban" <kol### [at] kolbancom> wrote:
> Ed,
> I am a newbie here too but my understanding is that with the b_spline, there
> are points before and after the ones that you want "visible" that direct the
> shapes entry and exit from the scene.
>
> Have a look at the following web page:
> http://www.cse.unsw.edu.au/~lambert/splines/Bspline.html
>
> You will notice that points '0' and '3' don't "show" in the curve but have a
> strong effect on how the curve starts and ends.
>
> Neil

Ah I see. In the meanwhile I had a look at
(http://www.povray.org/documentation/view/3.6.1/63/). Thanks anyway.

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