Why do I get "error:  Too few points in prism." ??  I said 7 points.. I see
7 points... what's the deal??

prism {
        cubic_spline
        0,
        1,
        7,
        <-3, -4>,
        <-3,  3>,
        < 2,  4>,
        < 2,  0>,
        < 3, -4>,
        <-3, -4>,
        < 2,  4>
        pigment {
                color green 1
        }
}

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On Thu, 10 Jan 2002 01:51:33 -0500, "Dayv" <gda### [at] homecom> wrote:

> Why do I get "error:  Too few points in prism." ??  I said 7 points.. I see
> 7 points... what's the deal??

Works fine when you change 6th point with value of 2nd.

analyze comments from 3.5 documentation example, note where is <0,0>

prism {
   cubic_spline
   0, 1, 7,
   <1,-1>, <0,0>, <6,0>, //outer rim; First control is <1,-1> and
   <6,8>, <0,8>, <0,0>,  //<0,0> is first & last point.
   <-1,1>,               //Last control of first spline is <-1,1>
 }

"In the cubic_spline, each sub-prism needs two additional control points -- one
at the beginning of each sub-prisms' point sequence to determine the slope at
the start of the curve and one at the end. The first point specified is the
control point which is not actually part of the spline. The second point is the
start of the spline. The sub-prism ends when this second point is duplicated.
The next point is the control point of the end of the first sub-prism. Next is
the beginning control point of the next sub-prism. The point after that is the
first point of the second sub-prism."

ABX

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duh... I forgot to close it up!  should have been 8 points!  sigh.  That's
what I get for writing pov code at 2am!

Thanks!
-Dayv



news:kboq3uonjmoe0c1aaehn9m4b10o2ad9ml4@4ax.com...
> On Thu, 10 Jan 2002 01:51:33 -0500, "Dayv" <gda### [at] homecom>
wrote:
>
> > Why do I get "error:  Too few points in prism." ??  I said 7 points.. I
see
> > 7 points... what's the deal??
>
> Works fine when you change 6th point with value of 2nd.
>
> analyze comments from 3.5 documentation example, note where is <0,0>
>
> prism {
>    cubic_spline
>    0, 1, 7,
>    <1,-1>, <0,0>, <6,0>, //outer rim; First control is <1,-1> and
>    <6,8>, <0,8>, <0,0>,  //<0,0> is first & last point.
>    <-1,1>,               //Last control of first spline is <-1,1>
>  }
>
> "In the cubic_spline, each sub-prism needs two additional control
points -- one
> at the beginning of each sub-prisms' point sequence to determine the slope
at
> the start of the curve and one at the end. The first point specified is
the
> control point which is not actually part of the spline. The second point
is the
> start of the spline. The sub-prism ends when this second point is
duplicated.
> The next point is the control point of the end of the first sub-prism.
Next is
> the beginning control point of the next sub-prism. The point after that is
the
> first point of the second sub-prism."
>
> ABX

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