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Subject: | Re: [geda-user] Apollon |
From: | John Doty <jpd AT noqsi DOT com> |
In-Reply-To: | <201509131824.t8DIOCBc028428@envy.delorie.com> |
Date: | Sun, 13 Sep 2015 13:04:31 -0600 |
Message-Id: | <798E233F-19D4-435C-B6E2-DC6BD352CB4E@noqsi.com> |
References: | <20150913140631 DOT 1da1b78d AT jive DOT levalinux DOT org> <201509131529 DOT t8DFTUVS022118 AT envy DOT delorie DOT com> <B0EDB76E-F0DE-4A05-97FC-A405489ACA5A AT noqsi DOT com> <201509131824 DOT t8DIOCBc028428 AT envy DOT delorie DOT com> |
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On Sep 13, 2015, at 12:24 PM, DJ Delorie <dj AT delorie DOT com> wrote: > >> If you do this right, you wind up with *exact* knowledge of every >> point in the x/y Cartesian geometry. Sines and cosines of these >> angles are rational numbers. No roundoff error. You can choose any >> unit basis you want (I'd go with meters). > > I thought of this for arcs - define the endpoints and the radius, not > the center and angles (there are other issues in this example, but > still). You're limited to what snaps to your grid, but if your grid > is nanometers that's a very small error. > > You do tend to go off-angle pretty quickly though, since so many > angles result in irrational numbers. > John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ jpd AT noqsi DOT com
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