+1 to start, end and .... +0 to whatever ... is. > On 10 Jul 2019, at 18:37, Larry Doolittle <ldool...@recycle.lbl.gov> wrote: > > Jon - > > On Wed, Jul 10, 2019 at 01:29:11PM -0400, Jon Evans wrote: >> I am curious why start-midpoint-end is better than start-center-end, though. >> I think the latter is used more often in mcad tools, although I could be >> wrong. > > start-center-end is mathematically over-constrained, so it sounds > worth avoiding. > > start-midpoint-end encodes a useless -- but not over-constrining -- > degree of freedom, in the position along the arc of the "midpoint". > > The mathematically correct number of parameters is five, and Seth makes > a good case that four of them should be the start and end coordinates. > One non-pathological definition of the fifth parameter is curvature, > in units of inverse-distance. Zero is no curvature -- converts back to > a straight line. The sign of the curvature tells whether the arc bends > left or right. I _don't_ assert that this is any better in real life than > start-midpoint-end. > > - Larry > > _______________________________________________ > Mailing list: https://launchpad.net/~kicad-developers > Post to : kicad-developers@lists.launchpad.net > Unsubscribe : https://launchpad.net/~kicad-developers > More help : https://help.launchpad.net/ListHelp
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