CGAL 5.6 - Polygon Mesh Processing

Functions to compute unit normals for individual/all vertices or faces.

Functions

template<typename PolygonMesh , typename NamedParameters = parameters::Default_named_parameters>
Vector_3 CGAL::Polygon_mesh_processing::compute_face_normal (typename boost::graph_traits< PolygonMesh >::face_descriptor f, const PolygonMesh &pmesh, const NamedParameters &np=parameters::default_values())
 computes the outward unit vector normal to face f. More...
 
template<typename PolygonMesh , typename Face_normal_map , typename NamedParameters = parameters::Default_named_parameters>
void CGAL::Polygon_mesh_processing::compute_face_normals (const PolygonMesh &pmesh, Face_normal_map face_normals, const NamedParameters &np=parameters::default_values())
 computes the outward unit vector normal for all faces of the polygon mesh. More...
 
template<typename PolygonMesh , typename NamedParameters = parameters::Default_named_parameters>
Vector_3 CGAL::Polygon_mesh_processing::compute_vertex_normal (typename boost::graph_traits< PolygonMesh >::vertex_descriptor v, const PolygonMesh &pmesh, const NamedParameters &np=parameters::default_values())
 computes the unit normal at vertex v as a function of the normals of incident faces. More...
 
template<typename PolygonMesh , typename VertexNormalMap , typename NamedParameters = parameters::Default_named_parameters>
void CGAL::Polygon_mesh_processing::compute_vertex_normals (const PolygonMesh &pmesh, VertexNormalMap vertex_normals, const NamedParameters &np=parameters::default_values())
 computes the outward unit vector normal for all vertices of the polygon mesh. More...
 
template<typename PolygonMesh , typename VertexNormalMap , typename FaceNormalMap , typename NamedParameters = parameters::Default_named_parameters>
void CGAL::Polygon_mesh_processing::compute_normals (const PolygonMesh &pmesh, VertexNormalMap vertex_normals, FaceNormalMap face_normals, const NamedParameters &np=parameters::default_values())
 computes the outward unit vector normal for all vertices and faces of the polygon mesh. More...
 

Function Documentation

◆ compute_face_normal()

template<typename PolygonMesh , typename NamedParameters = parameters::Default_named_parameters>
Vector_3 CGAL::Polygon_mesh_processing::compute_face_normal ( typename boost::graph_traits< PolygonMesh >::face_descriptor  f,
const PolygonMesh &  pmesh,
const NamedParameters &  np = parameters::default_values() 
)

#include <CGAL/Polygon_mesh_processing/compute_normal.h>

computes the outward unit vector normal to face f.

Template Parameters
PolygonMesha model of FaceGraph
NamedParametersa sequence of Named Parameters
Parameters
fthe face whose normal is computed
pmeshthe polygon mesh containing f
npan optional sequence of Named Parameters among the ones listed below
Optional Named Parameters
  • a property map associating points to the vertices of pmesh
  • Type: a class model of ReadablePropertyMap with boost::graph_traits<PolygonMesh>::vertex_descriptor as key type and Point_3 as value type
  • Default: boost::get(CGAL::vertex_point, pmesh)
  • Extra: If this parameter is omitted, an internal property map for CGAL::vertex_point_t must be available in PolygonMesh.

  • an instance of a geometric traits class
  • Type: a class model of Kernel
  • Default: a CGAL Kernel deduced from the point type, using CGAL::Kernel_traits
  • Extra: The geometric traits class must be compatible with the vertex point type.
Returns
the computed normal. The return type is a 3D vector type. It is either deduced from the geom_traits Named Parameters if provided, or from the geometric traits class deduced from the point property map of pmesh.
Warning
This function involves a square root computation. If the field type (FT) of the traits does not support the sqrt() operation, the square root computation will be performed approximately.
See also
compute_face_normals()

◆ compute_face_normals()

template<typename PolygonMesh , typename Face_normal_map , typename NamedParameters = parameters::Default_named_parameters>
void CGAL::Polygon_mesh_processing::compute_face_normals ( const PolygonMesh &  pmesh,
Face_normal_map  face_normals,
const NamedParameters &  np = parameters::default_values() 
)

#include <CGAL/Polygon_mesh_processing/compute_normal.h>

computes the outward unit vector normal for all faces of the polygon mesh.

Template Parameters
PolygonMesha model of FaceGraph
Face_normal_mapa model of WritablePropertyMap with boost::graph_traits<PolygonMesh>::face_descriptor as key type and Kernel::Vector_3 as value type.
Parameters
pmeshthe polygon mesh
face_normalsthe property map in which the normals are written
npan optional sequence of Named Parameters among the ones listed below
Optional Named Parameters
  • a property map associating points to the vertices of pmesh
  • Type: a class model of ReadablePropertyMap with boost::graph_traits<PolygonMesh>::vertex_descriptor as key type and Point_3 as value type
  • Default: boost::get(CGAL::vertex_point, pmesh)
  • Extra: If this parameter is omitted, an internal property map for CGAL::vertex_point_t must be available in PolygonMesh.

  • an instance of a geometric traits class
  • Type: a class model of Kernel
  • Default: a CGAL Kernel deduced from the point type, using CGAL::Kernel_traits
  • Extra: The geometric traits class must be compatible with the vertex point type.
Warning
This function involves a square root computation. If the field type (FT) of the traits does not support the sqrt() operation, the square root computation will be performed approximately.
See also
compute_face_normal()

◆ compute_normals()

template<typename PolygonMesh , typename VertexNormalMap , typename FaceNormalMap , typename NamedParameters = parameters::Default_named_parameters>
void CGAL::Polygon_mesh_processing::compute_normals ( const PolygonMesh &  pmesh,
VertexNormalMap  vertex_normals,
FaceNormalMap  face_normals,
const NamedParameters &  np = parameters::default_values() 
)

#include <CGAL/Polygon_mesh_processing/compute_normal.h>

computes the outward unit vector normal for all vertices and faces of the polygon mesh.

Template Parameters
PolygonMesha model of FaceListGraph
VertexNormalMapa model of WritablePropertyMap with boost::graph_traits<PolygonMesh>::vertex_descriptor as key type and Kernel::Vector_3 as value type.
FaceNormalMapa model of ReadWritePropertyMap with boost::graph_traits<PolygonMesh>::face_descriptor as key type and Kernel::Vector_3 as value type.
Parameters
pmeshthe polygon mesh
vertex_normalsthe property map in which the vertex normals are written
face_normalsthe property map in which the face normals are written
npan optional sequence of Named Parameters among the ones listed below
Optional Named Parameters
  • a property map associating points to the vertices of pmesh
  • Type: a class model of ReadablePropertyMap with boost::graph_traits<PolygonMesh>::vertex_descriptor as key type and Point_3 as value type
  • Default: boost::get(CGAL::vertex_point, pmesh)
  • Extra: If this parameter is omitted, an internal property map for CGAL::vertex_point_t must be available in PolygonMesh.

  • an instance of a geometric traits class
  • Type: a class model of Kernel
  • Default: a CGAL Kernel deduced from the point type, using CGAL::Kernel_traits
  • Extra: The geometric traits class must be compatible with the vertex point type.
Warning
This function involves a square root computation. If the field type (FT) of the traits does not support the sqrt() operation, the square root computation will be performed approximately.
See also
compute_vertex_normals()
compute_face_normals()
Examples:
Polygon_mesh_processing/compute_normals_example.cpp, and Polygon_mesh_processing/compute_normals_example_Polyhedron.cpp.

◆ compute_vertex_normal()

template<typename PolygonMesh , typename NamedParameters = parameters::Default_named_parameters>
Vector_3 CGAL::Polygon_mesh_processing::compute_vertex_normal ( typename boost::graph_traits< PolygonMesh >::vertex_descriptor  v,
const PolygonMesh &  pmesh,
const NamedParameters &  np = parameters::default_values() 
)

#include <CGAL/Polygon_mesh_processing/compute_normal.h>

computes the unit normal at vertex v as a function of the normals of incident faces.

The implementation is inspired by Aubry et al. "On the most 'normal' normal" [2], which aims to compute a normal that maximises the visibility to the incident faces. If such normal does not exist or if the optimization process fails to find it, a fallback normal is computed as a sine-weighted sum of the normals of the incident faces.

Note
The function compute_vertex_normals() should be preferred if normals are intended to be computed at all vertices of the graph.
Template Parameters
PolygonMesha model of FaceGraph
Parameters
vthe vertex whose normal is computed
pmeshthe polygon mesh containing v
npan optional sequence of Named Parameters among the ones listed below
Optional Named Parameters
  • a property map associating points to the vertices of pmesh
  • Type: a class model of ReadablePropertyMap with boost::graph_traits<PolygonMesh>::vertex_descriptor as key type and Point_3 as value type
  • Default: boost::get(CGAL::vertex_point, pmesh)
  • Extra: If this parameter is omitted, an internal property map for CGAL::vertex_point_t must be available in PolygonMesh.

  • an instance of a geometric traits class
  • Type: a class model of Kernel
  • Default: a CGAL Kernel deduced from the point type, using CGAL::Kernel_traits
  • Extra: The geometric traits class must be compatible with the vertex point type.
Returns
the computed normal. The return type is a 3D vector type. It is either deduced from the geom_traits Named Parameters if provided, or the geometric traits class deduced from the point property map of pmesh.
Warning
This function involves a square root computation. If the field type (FT) of the traits does not support the sqrt() operation, the square root computation will be performed approximately.
See also
compute_vertex_normals()

◆ compute_vertex_normals()

template<typename PolygonMesh , typename VertexNormalMap , typename NamedParameters = parameters::Default_named_parameters>
void CGAL::Polygon_mesh_processing::compute_vertex_normals ( const PolygonMesh &  pmesh,
VertexNormalMap  vertex_normals,
const NamedParameters &  np = parameters::default_values() 
)

#include <CGAL/Polygon_mesh_processing/compute_normal.h>

computes the outward unit vector normal for all vertices of the polygon mesh.

Template Parameters
PolygonMesha model of FaceListGraph
VertexNormalMapa model of WritablePropertyMap with boost::graph_traits<PolygonMesh>::vertex_descriptor as key type and the return type of compute_vertex_normal() as value type.
Parameters
pmeshthe polygon mesh
vertex_normalsthe property map in which the normals are written
npan optional sequence of Named Parameters among the ones listed below
Optional Named Parameters
  • a property map associating points to the vertices of pmesh
  • Type: a class model of ReadablePropertyMap with boost::graph_traits<PolygonMesh>::vertex_descriptor as key type and Point_3 as value type
  • Default: boost::get(CGAL::vertex_point, pmesh)
  • Extra: If this parameter is omitted, an internal property map for CGAL::vertex_point_t must be available in PolygonMesh.

  • an instance of a geometric traits class
  • Type: a class model of Kernel
  • Default: a CGAL Kernel deduced from the point type, using CGAL::Kernel_traits
  • Extra: The geometric traits class must be compatible with the vertex point type.
Warning
This function involves a square root computation. If the field type (FT) of the traits does not support the sqrt() operation, the square root computation will be performed approximately.
See also
compute_vertex_normal()
Examples:
Polygon_mesh_processing/extrude.cpp.