# 3.3.3.55. NXcg_sphere_set¶

**Status**:

base class, extends NXobject

**Description**:

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

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

Each sphere can have a different radius.

**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 circles or spheres.

**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 spheres. 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 spheres for explicit indexing.

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

Geometric center of the spheres. This can be the center of mass. Dimensionality and cardinality of the point and sphere 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 spheres.

radius: (optional) NX_NUMBER {units=NX_LENGTH}In the case that all spheres have the same radius.

radii: (optional) NX_NUMBER (Rank: 1, Dimensions: [c]) {units=NX_LENGTH}## In the case that spheres have different radius use this ...

In the case that spheres have different radius use this instead of the radius field.

is_closed: (optional) NX_BOOLEAN (Rank: 1, Dimensions: [c])Are the spheres 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}

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.