- From: L. David Baron <dbaron@dbaron.org>
- Date: Sat, 26 Nov 2011 16:19:45 -0800
- To: Daniel Glazman <daniel.glazman@disruptive-innovations.com>
- Cc: www-style@w3.org
On Saturday 2011-11-26 10:11 +0100, Daniel Glazman wrote: > Le 25/11/11 20:46, L. David Baron a Γ©crit : > > >Does anything define what it means to be clockwise around an axis? > >Clockwise and counterclockwise make sense in terms of a plane and an > >observer on one side of that plane, but I don't know what they mean > >in terms of an axis. Can we use the right-hand rule instead? Or > >can we define that the relevant axis points from the plane to the > >observer or vice-versa? > > The latter. Defining ckw rotation around an axis is trivial: place an > observer on a plane orthogonal to that axis, looking towards positive > axis values; then rotate the plan clockwise for the observer around the > axis. See, if I'd have had to make up a definition, I'd have had the observer looking *from* positive axis values, which would yield the opposite results. That's why I don't like using the term, and definitely don't like using it without defining it. -David -- π L. David Baron http://dbaron.org/ π π’ Mozilla http://www.mozilla.org/ π
Received on Sunday, 27 November 2011 00:20:14 UTC