# 3.3.3.42. NXcg_ellipsoid_set¶

**Status**:

base class, extends NXobject

**Description**:

## Computational geometry description of a set of ellipsoids in Euclidean space. ...

Computational geometry description of a set of ellipsoids in Euclidean space.

Individual ellipsoids can have different half axes.

**Symbols**:

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

d: The dimensionality, which has to be at least 2.

c: The cardinality of the set, i.e. the number of ellipses, or ellipsoids.

**Groups cited**:

**Structure**:

dimensionality: (optional) NX_POSINT {units=NX_UNITLESS}

cardinality: (optional) NX_POSINT {units=NX_UNITLESS}

identifier_offset: (optional) NX_INT {units=NX_UNITLESS}## Integer which specifies the first index to be used for distinguishing ...

Integer which specifies the first index to be used for distinguishing identifiers for ellipsoids. Identifiers are defined either implicitly or explicitly. For implicit indexing the identifiers are defined on the interval [identifier_offset, identifier_offset+c-1]. For explicit indexing the identifier array has to be defined.

The identifier_offset field can for example be used to communicate if the identifiers are expected to start from 1 (referred to as Fortran-/Matlab-) or from 0 (referred to as C-, Python-style index notation) respectively.

identifier: (optional) NX_INT (Rank: 1, Dimensions: [c]) {units=NX_UNITLESS}Integer used to distinguish ellipsoids for explicit indexing.

center: (optional) NX_NUMBER (Rank: 2, Dimensions: [c, d]) {units=NX_LENGTH}## Geometric center of the ellipsoids. This can be the center of mass. ...

Geometric center of the ellipsoids. This can be the center of mass. Dimensionality and cardinality of the point and ellipsoid set have to match. The identifier_offset and identifier field of NXcg_point_set do not need to be used as they should be same as the identifier_offset and the identifier for the ellipsoids.

half_axes_radius: (optional) NX_NUMBER (Rank: 1, Dimensions: [d]) {units=NX_LENGTH}If all ellipsoids in the set have the same half-axes.

half_axes_radii: (optional) NX_NUMBER (Rank: 2, Dimensions: [c, d]) {units=NX_LENGTH}## In the case that ellipsoids have different radii use this field ...

In the case that ellipsoids have different radii use this field instead of half_axes_radius.

is_closed: (optional) NX_BOOLEAN (Rank: 1, Dimensions: [c])Are the ellipsoids closed or hollow?

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

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

orientation: (optional) NX_NUMBER (Rank: 2, Dimensions: [c, d]) {units=NX_DIMENSIONLESS}Direction unit vector which points along the largest half-axes.

TRANSFORMATIONS: (optional) NXtransformations## Reference to or definition of a coordinate system with ...

Reference to or definition of a coordinate system with which the positions and directions are interpretable.

## Hypertext Anchors¶

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