POV-Ray : Newsgroups : povray.beta-test : [SOR] Bug still there ... : Re: [SOR] Bug still there ... Server Time
31 Jul 2024 04:15:00 EDT (-0400)
  Re: [SOR] Bug still there ...  
From: Ron Parker
Date: 28 Sep 2001 10:28:38
Message: <slrn9r928n.5an.ron.parker@fwi.com>
On 28 Sep 2001 10:20:14 -0400, Ron Parker wrote:
>On Fri, 28 Sep 2001 00:29:01 -0400, Nathan Kopp wrote:
>>
>>"Jan Walzer" <jan### [at] lzernet> wrote...
>>>     sor {
>>>         #declare Value=0.2
>>>        5,
>>>        <0.0,   -1.0>
>>>        <0.0,   -0.5>
>>>        <Value,   0.5>   // <------ change Value to 0.15 or lower ... and
>>see
>>
>>It is possible that the first two points, combined with a third point with a
>>height of 0.15, will cause the cubic spline to dip below a height of 0.0.
>>That would cause problems for the root solver.  Render with the values below
>>to see how the curve is concave, and how two zero-height points could cause
>>the SOR height to drop below 0.0.
>>
>>Therefore, this is not really a bug, but a strange limitation of the SOR
>>object.
>
>It might be a bounding thing, too.  I'm not sure the bounding routines really
>care for negative-radius cylinders.

In fact, having just gone through the bcyl routines looking for the other
SOR bug, I can testify that they do not like bounding cylinders where the
curve crosses 0, and are VERY likely to fail to render large chunks of the 
part of the spline contained in such an interval.

-- 
#local R=<7084844682857967,0787982,826975826580>;#macro L(P)concat(#while(P)chr(
mod(P,100)),#local P=P/100;#end"")#end background{rgb 1}text{ttf L(R.x)L(R.y)0,0
translate<-.8,0,-1>}text{ttf L(R.x)L(R.z)0,0translate<-1.6,-.75,-1>}sphere{z/9e3
4/26/2001finish{reflection 1}}//ron.parker@povray.org My opinions, nobody else's


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