Re: Interest for quaternions (and octonions)?

From: Hubert.Holin_at_[hidden]
Date: 2000-12-21 17:26:07

Paris (U.E.), le 21/12/2000

        Actually, the file I uploaded is one end product of soome work I 
did with a colleague about orientation interpolation (quaternions are 
superior to Euler angles, among other reasons because they are not 
succeptible to "gimbal lock", which is a degeneracy in the 
representation for special values of the orientation).

        The problem we solved (though this is *not* included in the public 
file), is that of orientation under constraint, i.e. if we want to 
emulate a real film camera, the "up" must not "wobble" between 
keyframes. I tried to licence that part, so far with no result :-<  .

        One thing which *is* in that file is the exponential of the 
quaternions, which I believe, is a result which I invented (more 
precisely, the closed formula giving the result is my invention, not 
the existence of the exponential (of one stripe or another) on the 
quaternions...). This can be used to achieve interpolation of 
orientations (in 3d-space), but with the "woble"...

        A last note: I have some ideas about cryptography and quaternions, 
but the implementation I proposed is not the best suited to this 
problem.

                Hubert Holin
                Hubert.Holin_at_[hidden]

--- In boost_at_[hidden], Lutz Kettner <kettner_at_i...> wrote:
> Hi,
> 
> there is interest in the graphics community for quaternions as 
> a _good_ representation of 3d rotations and for the ArcBall user 
> interface interaction technique for rotations. They are also very
> nice for interpolating between two different orienations of a 
> 3d object. I don't know about numerics and quaternions.
> 
> Lutz Kettner 
> 
> ----------------------------------------------------------------------
> UNC Computer Science                       email: kettner_at_c...
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> Chapel Hill, NC 27599-3175, USA            fax:   [phone]
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