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

.. index::
    ! NXcg_alpha_complex (base class)
    ! cg_alpha_complex (base class)
    see: cg_alpha_complex (base class); NXcg_alpha_complex

.. _NXcg_alpha_complex:

==================
NXcg_alpha_complex
==================

**Status**:

  base class, extends :ref:`NXcg_primitive_set`

**Description**:

  .. collapse:: Computational geometry of alpha shapes or alpha wrappings about primitives. ...

      Computational geometry of alpha shapes or alpha wrappings about primitives.

      For details see:

      * https://dx.doi.org/10.1109/TIT.1983.1056714 for 2D,
      * https://dx.doi.org/10.1145/174462.156635 for 3D,
      * https://dl.acm.org/doi/10.5555/871114 for weighted, and
      * https://doc.cgal.org/latest/Alpha_shapes_3 for 3D implementation
      * https://doc.cgal.org/latest/Manual/packages.html#PkgAlphaWrap3 for 3D wrappings

      in CGAL, the Computational Geometry Algorithms Library.
      As a starting point, we follow the conventions of the CGAL library.

**Symbols**:

  No symbol table

**Groups cited**:
  :ref:`NXcg_point_set`, :ref:`NXcg_tetrahedron_set`, :ref:`NXcg_triangle_set`

.. index:: NXcg_point_set (base class); used in base class, NXcg_triangle_set (base class); used in base class, NXcg_tetrahedron_set (base class); used in base class

**Structure**:

  .. _/NXcg_alpha_complex/type-field:

  .. index:: type (field)

  **type**: (optional) :ref:`NX_CHAR <NX_CHAR>` 

    .. collapse:: Type of alpha complex following the terminology used by CGAL for now. ...

        Type of alpha complex following the terminology used by CGAL for now.

        Basic means (unweighted) alpha shapes. Alpha_wrapping means meshes
        created using the alpha_wrapping algorithm.

        Any of these values: ``convex_hull`` | ``alpha_shape`` | ``alpha_wrapping``

  .. _/NXcg_alpha_complex/regularize_alpha_complex-field:

  .. index:: regularize_alpha_complex (field)

  **regularize_alpha_complex**: (optional) :ref:`NX_BOOLEAN <NX_BOOLEAN>` 

    .. collapse:: Are singular faces removed, i.e. has the alpha complex ...

        Are singular faces removed, i.e. has the alpha complex
        been regularized or not.

  .. _/NXcg_alpha_complex/alpha-field:

  .. index:: alpha (field)

  **alpha**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`} 

    .. collapse:: The alpha parameter, i.e. the radius of the alpha-sphere that ...

        The alpha parameter, i.e. the radius of the alpha-sphere that
        is used when computing the alpha complex.

  .. _/NXcg_alpha_complex/offset-field:

  .. index:: offset (field)

  **offset**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`} 

    The offset distance parameter used when computing alpha_wrappings.

  .. _/NXcg_alpha_complex/point_setID-group:

  **point_setID**: (optional) :ref:`NXcg_point_set` 

    Point cloud for which the alpha shape or wrapping has been computed.

  .. _/NXcg_alpha_complex/triangle_setID-group:

  **triangle_setID**: (optional) :ref:`NXcg_triangle_set` 

    Triangle soup for which the alpha wrapping has been computed.

  .. _/NXcg_alpha_complex/triangle_meshID-group:

  **triangle_meshID**: (optional) :ref:`NXcg_triangle_set` 

    Triangle mesh representing the alpha complex.

  .. _/NXcg_alpha_complex/interior_cellsID-group:

  **interior_cellsID**: (optional) :ref:`NXcg_tetrahedron_set` 

    Set of tetrahedra representing the volume inside the alpha complex.


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

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


* :ref:`/NXcg_alpha_complex/alpha-field </NXcg_alpha_complex/alpha-field>`
* :ref:`/NXcg_alpha_complex/interior_cellsID-group </NXcg_alpha_complex/interior_cellsID-group>`
* :ref:`/NXcg_alpha_complex/offset-field </NXcg_alpha_complex/offset-field>`
* :ref:`/NXcg_alpha_complex/point_setID-group </NXcg_alpha_complex/point_setID-group>`
* :ref:`/NXcg_alpha_complex/regularize_alpha_complex-field </NXcg_alpha_complex/regularize_alpha_complex-field>`
* :ref:`/NXcg_alpha_complex/triangle_meshID-group </NXcg_alpha_complex/triangle_meshID-group>`
* :ref:`/NXcg_alpha_complex/triangle_setID-group </NXcg_alpha_complex/triangle_setID-group>`
* :ref:`/NXcg_alpha_complex/type-field </NXcg_alpha_complex/type-field>`

**NXDL Source**:
  https://github.com/FAIRmat-NFDI/nexus_definitions/tree/fairmat/contributed_definitions/NXcg_alpha_complex.nxdl.xml