3.3.1.31. NXcg_alpha_complex

Status:

base class, extends NXcg_primitive

Description:

Computational geometry of alpha complexes (alpha shapes or alpha wrappings) abou …

Computational geometry of alpha complexes (alpha shapes or alpha wrappings) about primitives.

For details see:

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

In general, an alpha complex is a not necessarily connected or not necessarily pure complex, i.e. singular faces may exist. The number of cells, faces, and edges depends on how a specific alpha complex is filtered for lower-dimensional simplices. The fields is_regularized and regularization can be used to provide details about regularization procedures.

Symbols:

No symbol table

Groups cited:

NXcg_point, NXcg_tetrahedron, NXcg_triangle

Structure:

type: (optional) NX_CHAR

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

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

Alpha_shape means meshes created using one of the alpha_shape algorithm. Alpha_wrapping means meshes created using the alpha_wrapping algorithm.

Any of these values: convex_hull | alpha_shape | alpha_wrapping

regularization: (optional) NX_CHAR

Human-readable description about regularization procedures.

is_regularized: (optional) NX_BOOLEAN

Was the alpha complex regularized, i.e. have singular faces been removed, or not.

alpha: (optional) NX_NUMBER {units=NX_ANY}

The alpha parameter, i.e. the squared radius of the alpha-sphere …

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

offset: (optional) NX_NUMBER {units=NX_LENGTH}

The offset distance parameter used when computing alpha_wrappings.

CG_POINT: (optional) NXcg_point

Point cloud serving as input for the computation of the alpha complex.

TRIANGLE_SOUP: (optional) NXcg_triangle

Triangle soup serving as input for the computation of the alpha complex.

ALPHA_COMPLEX: (optional) NXcg_triangle

Triangle mesh representing the output of the computation, i.e. the alpha complex.

TETRAHEDRALIZATION: (optional) NXcg_tetrahedron

Tetrahedra representing an interior volume of the alpha complex (if such exists).

Hypertext Anchors

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

NXDL Source:

https://github.com/nexusformat/definitions/blob/main/base_classes/NXcg_alpha_complex.nxdl.xml