2.3.3.3.185. NXrotation_set

Status:

base class, extends NXobject

Description:

Base class to detail a set of rotations, orientations, and disorientations. ...

Base class to detail a set of rotations, orientations, and disorientations.

For getting a more detailed insight into the discussion of the parameterized description of orientations in materials science see:

Once orientations are defined, one can continue to characterize the misorientation and specifically the disorientation. The misorientation describes the rotation that is required to register the lattices of two oriented objects (like crystal lattice) into a crystallographic equivalent orientation:

Symbols:

The symbols used in the schema to specify e.g. dimensions of arrays.

c: The cardinality of the set, i.e. the number of value tuples.

n_phases: How many phases with usually different crystal and symmetry are distinguished.

Groups cited:

none

Structure:

depends_on: (optional) NX_CHAR

Reference to an instance of :ref:`NXcoordinate_system_set` which contextualize ...

Reference to an instance of NXcoordinate_system_set which contextualizes how the here reported parameterized quantities can be interpreted.

crystal_symmetry: (optional) NX_CHAR (Rank: 1, Dimensions: [n_phases])

Point group which defines the symmetry of the crystal. ...

Point group which defines the symmetry of the crystal.

This has to be at least a single string. If crystal_symmetry is not provided point group 1 is assumed.

In the case that misorientation or disorientation fields are used and the two crystal sets resolve for phases with a different crystal symmetry, this field has to encode two string. In this case the first string is for phase A the second one for phase B. An example of this most complex case is the description of the disorientation between crystals adjoining a hetero-phase boundary.

sample_symmetry: (optional) NX_CHAR (Rank: 1, Dimensions: [n_phases])

Point group which defines an assumed symmetry imprinted upon processing ...

Point group which defines an assumed symmetry imprinted upon processing the material/sample which could give rise to or may justify to use a simplified description of rotations, orientations, misorientations, and disorientations via numerical procedures that are known as symmetrization.

If sample_symmetry is not provided point group 1 is assumed.

The traditionally used symmetrization operations within the texture community in Materials Science, though, are thanks to methodology and software improvements no longer strictly needed. Therefore, users are encouraged to set the sample_symmetry to 1 (triclinic) and thus assume there is no justification to assume the imprinting of additional symmetry because of the processing.

In practice one often faces situations where indeed these assumed symmetries are anyway not fully observed, and thus an accepting of eventual inaccuracies just for the sake of reporting a simplified symmetrized description should be avoided.

rotation_quaternion: (optional) NX_NUMBER (Rank: 2, Dimensions: [c, 4]) {units=NX_DIMENSIONLESS}

The set of rotations expressed in quaternion parameterization considering ...

The set of rotations expressed in quaternion parameterization considering crystal_symmetry and sample_symmetry. Rotations which should be interpreted as antipodal are not marked as such.

rotation_euler: (optional) NX_NUMBER (Rank: 2, Dimensions: [c, 3]) {units=NX_ANGLE}

The set of rotations expressed in Euler angle parameterization considering ...

The set of rotations expressed in Euler angle parameterization considering the same applied symmetries as detailed for the field rotation_quaternion. To interpret Euler angles correctly, it is necessary to inspect the conventions behind depends_on to resolve which of the many Euler-angle conventions possible (Bunge ZXZ, XYZ, Kocks, Tait, etc.) were used.

is_antipodal: (optional) NX_BOOLEAN (Rank: 1, Dimensions: [c])

True for all those value tuples which have assumed antipodal symmetry. ...

True for all those value tuples which have assumed antipodal symmetry. False for all others.

orientation_quaternion: (optional) NX_NUMBER (Rank: 2, Dimensions: [c, 4]) {units=NX_DIMENSIONLESS}

The set of orientations expressed in quaternion parameterization and ...

The set of orientations expressed in quaternion parameterization and obeying symmetry for equivalent cases as detailed in crystal_symmetry and sample_symmetry. The supplementary field is_antipodal can be used to mark orientations with the antipodal property.

orientation_euler: (optional) NX_NUMBER (Rank: 2, Dimensions: [c, 3]) {units=NX_ANGLE}

The set of orientations expressed in Euler angle parameterization following ...

The set of orientations expressed in Euler angle parameterization following the same assumptions like for orientation_quaternion. To interpret Euler angles correctly, it is necessary to inspect the conventions behind depends_on to resolve which of the many Euler-angle conventions possible (Bunge ZXZ, XYZ, Kocks, Tait, etc.) were used.

misorientation_quaternion: (optional) NX_NUMBER (Rank: 2, Dimensions: [c, 4]) {units=NX_DIMENSIONLESS}

The set of misorientations expressed in quaternion parameterization ...

The set of misorientations expressed in quaternion parameterization obeying symmetry operations for equivalent misorientations as defined by crystal_symmetry and sample_symmetry.

misorientation_angle: (optional) NX_NUMBER (Rank: 1, Dimensions: [c]) {units=NX_ANGLE}

Misorientation angular argument (eventually signed) following the same ...

Misorientation angular argument (eventually signed) following the same symmetry assumptions as expressed for the field misorientation_quaternion.

misorientation_axis: (optional) NX_NUMBER (Rank: 2, Dimensions: [c, 3]) {units=NX_DIMENSIONLESS}

Misorientation axis (normalized) and signed following the same ...

Misorientation axis (normalized) and signed following the same symmetry assumptions as expressed for the field misorientation_angle.

disorientation_quaternion: (optional) NX_NUMBER (Rank: 2, Dimensions: [c, 4]) {units=NX_DIMENSIONLESS}

The set of disorientation expressed in quaternion parameterization ...

The set of disorientation expressed in quaternion parameterization obeying symmetry operations for equivalent misorientations as defined by crystal_symmetry and sample_symmetry.

disorientation_angle: (optional) NX_NUMBER (Rank: 1, Dimensions: [c]) {units=NX_ANGLE}

Disorientation angular argument (should not be signed, see ...

Disorientation angular argument (should not be signed, see D. Rowenhorst et al.) following the same symmetry assumptions as expressed for the field disorientation_quaternion.

disorientation_axis: (optional) NX_NUMBER (Rank: 2, Dimensions: [c, 3]) {units=NX_DIMENSIONLESS}

Disorientation axis (normalized) following the same symmetry assumptions ...

Disorientation axis (normalized) following the same symmetry assumptions as expressed for the field disorientation_angle.

Hypertext Anchors

List of hypertext anchors for all groups, fields, attributes, and links defined in this class.

NXDL Source:

https://github.com/FAIRmat-NFDI/nexus_definitions/tree/fairmat/contributed_definitions/NXrotation_set.nxdl.xml