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Re: [css3-3d-transforms] rotations, changes needed...

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
Message-ID: <20111127001945.GA14866@pickering.dbaron.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„ž   L. David Baron                         http://dbaron.org/   𝄂
𝄒   Mozilla                           http://www.mozilla.org/   𝄂
Received on Sunday, 27 November 2011 00:20:14 GMT

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