Re: [CAD_CAM_EDM_DRO] Re: equation for locating the center of an arc knowing three points

Hi Charles,

Sorry! Thought you wanted a CAD solution! For an algorithm, you need
to create two cords (less then dia) to the circle, then erect
perpendiculars to the two cords. the intersection of the two lines is
the center. I think Machinery's Handbook has examples.

Alan KM6VV


Charles Hixon wrote:

>
> Hey Fred, Alan,
>
> Thanks, but those ideas about as fast as mine. I am really more
> interested in the equation to locate the center so I can finish
> generating the arrays in Excel.
>
> Charles
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Fred Smith" <imserv@v...>
> wrote:
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, Alan Marconett KM6VV
> > <KM6VV@a...> wrote:
> > > Hi Charles,
> > >
> > > I thought about recommending the Vector CAD (and probably
> others)
> > can
> > > find the center of an arc, or, as I did on a recent DXF import
> from
> > a
> > > Schematic capture program, edit on of the little arcs, and make
> it
> > a
> > > full circle (delete all the other fragments). Trouble is, I
> think
> > he
> > > has just short LINES, not ARCS. So it isn't as easy!
> >
> > The Vector, Arc-Spline function could be used. It fits arcs to
> cubic
> > splines or Nurbs curves and it has an arc-chordal error tolerance
> so
> > that an appropriate level of accuracy can be maintained in the
> > process. Most likely his software has something similar, just
> hard
> > to find it. ;-)
> >
> > Best Regards, Fred Smith- IMService
> >
> > Listserve Special discounts and offers are at:
> > http://www.imsrv.com/hobby
> >
> > We are THE source for low cost Cad Cam
>