POV-Ray : Newsgroups : povray.object-collection : SphereSweep 1.1, with B-splines : Re: SphereSweep 1.1, with B-splines Server Time
5 Dec 2021 00:49:55 EST (-0500)
  Re: SphereSweep 1.1, with B-splines  
From: And
Date: 5 Sep 2015 10:40:00
Message: <web.55eafdc7bb12a32f57fdff410@news.povray.org>
"Cousin Ricky" <rickysttATyahooDOTcom> wrote:
> "And" <49341109@ntnu.edu.tw> wrote:
> > Cousin Ricky <ric### [at] yahoocom> wrote:
> > >
> > > I am moving Bézier spline up on the priority list for a future version.
> > >   However, implementation will not be straightforward, due to the
> > > possibility of disjointed spline segments.
> >
> >
> > Hello, Cousin Ricky, I'm not sure that you have the plane to make the Bezier
> > spline sphere sweep macros during the next weeks. Basically I've written one, at
> >
> >
> > And maybe I will write a more general version that put a 'merge' feature and the
> > variant radius feature on it. We can discuss it.
> I began work on the Bezier sphere sweep last week.  The Bezier calculation macro
> is already complete, and accommodates variable radii.  The hard part is to
> integrate the Bezier calculation into my existing macros.
> I will take a look at your file.  Please be aware that the Object Collection
> requires the GNU Lesser General Public License (LGPL) 2.1, so if I end up
> borrowing any of your code, you will need to consent to offering that license
> before I can upload it.  The LGPL is just about the most generous license out
> there, leaving you with little more than token ownership of your intellectual
> property, so you'll want to read it very carefully before consenting to offer
> it.

Ok. Thank you very much.

Well, I wondering what the radius formula do others like you apply? I think that
it can be the similar form as the bezier curve in a sense:

r = r0*pow(1-t,3) + r1*pow(1-t,2)*t + r2*(1-t)*pow(t,2) + r3*pow(t,3)
0 <= t <= 1
That is, four points and four radii decide a segment.
Wondering how do you think?

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