Am I the only one that uses sphere_sweeps with linear_splines?

:-(

-- 
Jeremy
www.beantoad.com


"Jeremy M. Praay" <sla### [at] hotmailcom> wrote in message 
news:41dc9ae0$1@news.povray.org...
> Basically, if you take a sphere_sweep that's a linear_spline and scale it 
> rather small, you can get some very strange defects in the sphere_sweep. 
> Rotating the object and changing the scale seems to take care of the 
> problem in some cases.  I mentioned this quite awhile ago, but then I 
> never got back to it.  Additionally, it seems to worsened from 3.5 to 3.6.
>
> I would simply guess that the scale is too small (which can happen), 
> except for the fact that if you change it into a cubic_spline, the defect 
> goes away, and the sphere_sweep can be scaled much smaller.  I've scaled 
> sphere_sweeps in various sizes that were cubic_splines, and I've never 
> noticed this problem.
>
> Using the code below (complete scene meant to create an insect leg), you 
> can easily and quickly see how changing the scale from 0.3 to 0.05 
> increases the defect in the leg.  Rotating the leg can make the defect 
> disappear (in some cases), or make it much worse.  Uncommenting the code 
> in the "object" section (and keeping everything else) shows how the 
> problem can appear differently, depending on the rotation.
>
> Am I missing something?  Or is it a known issue?  Should this be reported 
> as a bug?
>
> (written for pov 3.6.1)
>
> ---------------
>
> camera {
>  location  <0.0, 0.5, -4.0>
>  look_at   <0.0, 0,  0.0>
> }
>
> background {rgb 1}
>
> #declare Leg=
>  sphere_sweep {
>    linear_spline
>    7,
>    <0,0>, 0.2,
>    <1,0>, 0.15,
>    <1.5,-1>, 0.15,
>    <3.75,-0.6>, 0.25,
>    <6,0>, 0.15,
>    <7,-4>, 0.1,
>    <8,-4.3>, 0.1
> }
>
> object { Leg
>  scale 0.2
>  //rotate x*-60
>  //rotate z*-40
>  //rotate y*52
>  //scale 0.2
> }
>
>
> -- 
> Jeremy
> www.beantoad.com
>

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