POV-Ray : Newsgroups : povray.advanced-users : Bezier spline deformation : Bezier spline deformation Server Time 7 Dec 2023 08:44:55 EST (-0500)
 Bezier spline deformation
 From: yesbird Date: 14 Mar 2023 07:01:55 Message: <64105423\$1@news.povray.org>
```
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Hi,

while working on C4D->POV converter, I've discovered a strange form
deviation of prism, extruded from bezier spline (see attachment).

I claim, that exported data is absolutely correct (checked many times),
and no any useful info found here:
https://www.povray.org/documentation/view/3.7.0/62/
https://wiki.povray.org/content/Reference:Prism

I'm not sure about collisions, but only wonder how the same data with
the algorithm can produce different results. It seams to me, that
interpretation is different or maybe some additional scaling is applied
to tangents, for example.

Code is below, any ideas ?

//----------------------------------------------------------------------------
camera{	perspective
location  <0, 0, 0>
angle 53.130102

matrix
<1.000000, -0.000000, 0.000000,
0.000000, 0.000000, 1.000000,
-0.000000, -1.000000, 0.000000,
0.058724, 5.575552, -0.059483>

}

#declare Extrude = prism { linear_sweep bezier_spline 0, 1.000000, 16

<1.500000, 0.000000>
<1.500000, 0.450694>
<0.450694, 1.000000>
<0.000000, 1.000000>
<0.000000, 1.000000>
<-0.450694, 1.000000>
<-1.500000, 0.450694>
<-1.500000, 0.000000>
<-1.500000, 0.000000>
<-1.500000, -0.450694>
<-0.450694, -1.000000>
<0.000000, -1.000000>
<0.000000, -1.000000>
<0.450694, -1.000000>
<1.500000, -0.450694>
<1.500000, 0.000000>
matrix
<1.000000, 0.000000, 0.000000,
0.000000, 1.000000, 0.000000,
0.000000, 0.000000, 1.000000,
0.000000, 0.000000, 0.000000>

material { mat_default }
}

object{ Extrude }
//----------------------------------------------------------------------------
```

Attachments: