.. auto-generated by dev_tools.docs.nxdl from the NXDL source contributed_definitions/NXcg_triangle_set.nxdl.xml -- DO NOT EDIT

.. index::
    ! NXcg_triangle_set (base class)
    ! cg_triangle_set (base class)
    see: cg_triangle_set (base class); NXcg_triangle_set

.. _NXcg_triangle_set:

=================
NXcg_triangle_set
=================

**Status**:

  base class, extends :ref:`NXobject`

**Description**:

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

**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 triangles.

  **n_unique**: The number of unique vertices supporting the triangles.

**Groups cited**:
  :ref:`NXcg_face_list_data_structure`, :ref:`NXcg_hexahedron_set`, :ref:`NXcg_unit_normal_set`, :ref:`NXtransformations`

.. index:: NXtransformations (base class); used in base class, NXcg_face_list_data_structure (base class); used in base class, NXcg_unit_normal_set (base class); used in base class, NXcg_hexahedron_set (base class); used in base class

**Structure**:

  .. _/NXcg_triangle_set/dimensionality-field:

  .. index:: dimensionality (field)

  **dimensionality**: (optional) :ref:`NX_POSINT <NX_POSINT>` {units=\ :ref:`NX_UNITLESS <NX_UNITLESS>`}


  .. _/NXcg_triangle_set/cardinality-field:

  .. index:: cardinality (field)

  **cardinality**: (optional) :ref:`NX_POSINT <NX_POSINT>` {units=\ :ref:`NX_UNITLESS <NX_UNITLESS>`}


  .. _/NXcg_triangle_set/number_of_unique_vertices-field:

  .. index:: number_of_unique_vertices (field)

  **number_of_unique_vertices**: (optional) :ref:`NX_POSINT <NX_POSINT>` {units=\ :ref:`NX_UNITLESS <NX_UNITLESS>`}


  .. _/NXcg_triangle_set/identifier_offset-field:

  .. index:: identifier_offset (field)

  **identifier_offset**: (optional) :ref:`NX_INT <NX_INT>` {units=\ :ref:`NX_UNITLESS <NX_UNITLESS>`}

    Integer which specifies the first index to be used for distinguishing
    triangles. 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.

  .. _/NXcg_triangle_set/identifier-field:

  .. index:: identifier (field)

  **identifier**: (optional) :ref:`NX_INT <NX_INT>` (Rank: 1, Dimensions: [c]) {units=\ :ref:`NX_UNITLESS <NX_UNITLESS>`}

    Integer used to distinguish triangles for explicit indexing.

  .. _/NXcg_triangle_set/area-field:

  .. index:: area (field)

  **area**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` (Rank: 1, Dimensions: [c]) {units=\ :ref:`NX_AREA <NX_AREA>`}


  .. _/NXcg_triangle_set/edge_length-field:

  .. index:: edge_length (field)

  **edge_length**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` (Rank: 2, Dimensions: [c, 3]) {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}

    Array of edge length values. For each triangle the edge length is
    reported for the edges traversed according to the sequence
    in which vertices are indexed in triangles.

  .. _/NXcg_triangle_set/interior_angle-field:

  .. index:: interior_angle (field)

  **interior_angle**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` (Rank: 2, Dimensions: [c, 3]) {units=\ :ref:`NX_ANGLE <NX_ANGLE>`}

    Array of interior angle values. For each triangle the angle is
    reported for the angle opposite to the edges which are traversed
    according to the sequence in which vertices are indexed in triangles.

  .. _/NXcg_triangle_set/center-field:

  .. index:: center (field)

  **center**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` (Rank: 2, Dimensions: [c, d]) {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}

    The center of mass of each polygon.

  .. _/NXcg_triangle_set/TRANSFORMATIONS-group:

  **TRANSFORMATIONS**: (optional) :ref:`NXtransformations`

    Reference to or definition of a coordinate system with
    which the qualifiers and primitive data are interpretable.

  .. _/NXcg_triangle_set/triangles-group:

  **triangles**: (optional) :ref:`NXcg_face_list_data_structure`

    A simple approach to describe the entire set of triangles when the
    main intention is to store the shape of the triangles for visualization.

  .. _/NXcg_triangle_set/vertex_normal-group:

  **vertex_normal**: (optional) :ref:`NXcg_unit_normal_set`


  .. _/NXcg_triangle_set/edge_normal-group:

  **edge_normal**: (optional) :ref:`NXcg_unit_normal_set`


  .. _/NXcg_triangle_set/face_normal-group:

  **face_normal**: (optional) :ref:`NXcg_unit_normal_set`


  .. _/NXcg_triangle_set/bounding_box-group:

  **bounding_box**: (optional) :ref:`NXcg_hexahedron_set`

    Axis-aligned or (approximate) (optimal) bounding boxes to each polygon.


Hypertext Anchors
-----------------

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


* :ref:`/NXcg_triangle_set/area-field </NXcg_triangle_set/area-field>`
* :ref:`/NXcg_triangle_set/bounding_box-group </NXcg_triangle_set/bounding_box-group>`
* :ref:`/NXcg_triangle_set/cardinality-field </NXcg_triangle_set/cardinality-field>`
* :ref:`/NXcg_triangle_set/center-field </NXcg_triangle_set/center-field>`
* :ref:`/NXcg_triangle_set/dimensionality-field </NXcg_triangle_set/dimensionality-field>`
* :ref:`/NXcg_triangle_set/edge_length-field </NXcg_triangle_set/edge_length-field>`
* :ref:`/NXcg_triangle_set/edge_normal-group </NXcg_triangle_set/edge_normal-group>`
* :ref:`/NXcg_triangle_set/face_normal-group </NXcg_triangle_set/face_normal-group>`
* :ref:`/NXcg_triangle_set/identifier-field </NXcg_triangle_set/identifier-field>`
* :ref:`/NXcg_triangle_set/identifier_offset-field </NXcg_triangle_set/identifier_offset-field>`
* :ref:`/NXcg_triangle_set/interior_angle-field </NXcg_triangle_set/interior_angle-field>`
* :ref:`/NXcg_triangle_set/number_of_unique_vertices-field </NXcg_triangle_set/number_of_unique_vertices-field>`
* :ref:`/NXcg_triangle_set/TRANSFORMATIONS-group </NXcg_triangle_set/TRANSFORMATIONS-group>`
* :ref:`/NXcg_triangle_set/triangles-group </NXcg_triangle_set/triangles-group>`
* :ref:`/NXcg_triangle_set/vertex_normal-group </NXcg_triangle_set/vertex_normal-group>`

**NXDL Source**:
  https://github.com/nexusformat/definitions/blob/main/contributed_definitions/NXcg_triangle_set.nxdl.xml