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

From: Alan Gresley <alan@css-class.com>
Date: Sun, 27 Nov 2011 22:18:24 +1100
Message-ID: <4ED21C80.7000001@css-class.com>
To: Daniel Glazman <daniel.glazman@disruptive-innovations.com>
CC: www-style@w3.org
On 26/11/2011 8:11 PM, Daniel Glazman wrote:
> Le 25/11/11 20:46, L. David Baron a écrit :
>
>> 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.
>
> </Daniel>

Both rotate() and rotateZ() are synonyms.

We have a box,

     -------------
     |           |
     |           |
     |     Z     |
     |           |
     |           |
     -------------

which can be painted at any level in the z-index. Without any transforms 
(rotation) on the X and and Y axises or transform-origin, the box will 
turn clockwise on it axis (marked with the letter Z). This center axis 
point is on a plane (represented here as a box) which has  it's central 
axis perpendicular to the plane of the observer.


-- 
Alan Gresley
http://css-3d.org/
http://css-class.com/
Received on Sunday, 27 November 2011 11:18:58 GMT

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