Transf WD Euler transformation
Laurent MICHEL
laurent.michel at astro.unistra.fr
Fri Apr 3 15:11:18 CEST 2020
Hello,
I do not practice Euler transformations daily, but according to my
college souvenirs, that is by definition a 3D rotation with a well
defined sequence of rotation axis.
In my understanding, the Euler rotation is even not a particular case of
the Transf rotation since the 3 Euler rotations are not about native
axis as stated in the definition you give.
> Defines a rotation operation in a 3-dimensional cartesian coordinate space, defined as a series of rotations about the native axes (x,y,z)
If I'm right, the class should be renamed (RotationSequence ?). If not,
my comment is no longer relevant.
Laurent
Le 02/04/2020 à 16:40, CresitelloDittmar, Mark a écrit :
> Laurent,
>
> This came directly from the implementation group discussions back in Dec
> 2018.
> gWCS has use cases where more than 3 rotations are useful, for example
> EulerRotation(angles=[12, 1, 2, 3], axes=‘xyzx’).
> So we've taken this approach of having a sequence of EulerAngles which
> specify the 'axis of rotation' (of the 3D space as either 'x', 'y', or
> 'z') and angle.
>
> Mark
>
>
> On Thu, Apr 2, 2020 at 8:31 AM Laurent MICHEL
> <laurent.michel at astro.unistra.fr
> <mailto:laurent.michel at astro.unistra.fr>> wrote:
>
> Dear,
>
> My comment #1: Why is the Euler Transformation class so complex?
>
> - It is always a 3D transformation, this there is no reason to setup a
> 1-* aggregation with angles.
>
> - Euler angles (nutation, rotation, intrinsic rotation) are well
> defined, there is no need for a specific datatype (EulerAngle). So we
> could just have 3 class attributes.
>
> - Using a specific datatype where angles are identified by a the
> name of
> the rotation axis supposes we have a vocabulary for this, which is a
> bit
> complicated for this purpose with the risk a implementation errors.
>
> Take care of yourself.
>
> LM
>
> --
> ---- Laurent MICHEL Tel (33 0) 3 68 85 24 37
> Observatoire de Strasbourg Fax (33 0) 3 68 85 24 32
> 11 Rue de l'Universite Mail
> laurent.michel at astro.unistra.fr <mailto:laurent.michel at astro.unistra.fr>
> 67000 Strasbourg (France) Web http://astro.u-strasbg.fr/~michel
> ---
>
--
---- Laurent MICHEL Tel (33 0) 3 68 85 24 37
Observatoire de Strasbourg Fax (33 0) 3 68 85 24 32
11 Rue de l'Universite Mail laurent.michel at astro.unistra.fr
67000 Strasbourg (France) Web http://astro.u-strasbg.fr/~michel
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