POV-Ray : Newsgroups : povray.pov4.discussion.general : New feature : Re: New feature Server Time
21 Feb 2024 23:19:45 EST (-0500)
  Re: New feature  
From: clipka
Date: 3 Feb 2009 07:20:00
Message: <web.4988364b805a7c7eea031d410@news.povray.org>
"JayWiz" <nomail@nomail> wrote:
> The normal lathe uses straight lines to connect the "dots". If a curve could be
> used then the polyline object from autocad (or TurboCAD which I also use) could
> be easily translated. The other lathe types are not really condusive to the
> objects I use.

"Curve" is a bit vague, as all the quadratic_spline, cubic_spline and
bezier_spline would fall into that category.

I just googled for what type of spline AutoCAD's "polyline" actually is,
mathematically, only to find that it's not a classic spline at all...

From a geometric point of view, a polyline lathe should be representable as an
(albeit possibly non-trivial) CSG object composed entirely of linear_spline
lathes and tori, and a polyline prism as a CSG object composed entirely of
standard linear_spline prisms and cylinders.


So that might be a point for the To-Do list: Implement a new spline type,
defining a path made up of straight lines and circular arcs.

Question to you as someone familiar with AutoCAD: How's a polyline actually
defined in AutoCAD? Is it basically a polygon, with corners rounded using a
standard radius? Is it a polygon with corners rounded using different radius
for each corner? Or a free intermix of straight lines and arcs?


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