POV-Ray : Newsgroups : povray.object-collection : Sphere Sweep 1.2 Quadratic spline question : Re: Sphere Sweep 1.2 Quadratic spline question Server Time: 26 Oct 2020 12:51:36 GMT
  Re: Sphere Sweep 1.2 Quadratic spline question  
From: Bald Eagle
Date: 31 Aug 2020 23:35:00
Cousin Ricky <ric### [at] yahoocom> wrote:

> SVG's quadratic curve uses 2nd order Bézier splines, while
> SSWP_QUADRATIC_SPLINE uses POV-Ray's built-in quadratic spline type,
> which connects the control points with parabolic curves.  They are two
> different spline types.

I /thought/ that might be the case.

> To get an SVG style quadratic curve, you would need to use
> SSWP_BEZIER_SPLINE, and clone the middle control point:

> Unfortunately, the Bézier algorithm in SphereSweep 1.2 does not handle
> such cloning properly.  You'll need to replace macro SSwp__Bezier_calc()
> in spheresweep.inc with the following:

Weird, but glad you had a quick fix all ready to plug in.  :)

> It is under consideration.  In any case, the Bézier algorithm patch will
> definitely be in the next update.


Thanks very much - that fixed the bumpiness of the outlines.
Now I have to figure out why the SVG splines render oh-so-very nicely in a
browser, but have all sorts of apparently extraneous lines and scribble when
converted over to sphere sweeps...


Post a reply to this message

Copyright 2003-2008 Persistence of Vision Raytracer Pty. Ltd.