Normal Computation

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

Functions
template<typename PolygonMesh , typename NamedParameters >
Vector_3	CGAL::Polygon_mesh_processing::compute_face_normal (typename boost::graph_traits< PolygonMesh >::face_descriptor f, const PolygonMesh &pmesh, const NamedParameters &np)
	computes the outward unit vector normal to face f. More...
template<typename PolygonMesh , typename FaceNormalMap , typename NamedParameters >
void	CGAL::Polygon_mesh_processing::compute_face_normals (const PolygonMesh &pmesh, FaceNormalMap fnm, const NamedParameters &np)
	computes the outward unit vector normal for all faces of the polygon mesh. More...
template<typename PolygonMesh , typename NamedParameters >
Vector_3	CGAL::Polygon_mesh_processing::compute_vertex_normal (typename boost::graph_traits< PolygonMesh >::vertex_descriptor v, const PolygonMesh &pmesh, const NamedParameters &np)
	computes the unit normal at vertex v as the average of the normals of incident faces. More...
template<typename PolygonMesh , typename VertexNormalMap , typename NamedParameters >
void	CGAL::Polygon_mesh_processing::compute_vertex_normals (const PolygonMesh &pmesh, VertexNormalMap vnm, const NamedParameters &np)
	computes the outward unit vector normal for all vertices of the polygon mesh. More...
template<typename PolygonMesh , typename VertexNormalMap , typename FaceNormalMap , typename NamedParameters >
void	CGAL::Polygon_mesh_processing::compute_normals (const PolygonMesh &pmesh, VertexNormalMap vnm, FaceNormalMap fnm, const NamedParameters &np)
	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 >

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

#include <CGAL/Polygon_mesh_processing/compute_normal.h>

computes the outward unit vector normal to face f.

Template Parameters

PolygonMesh	a model of FaceGraph
NamedParameters	a sequence of Named Parameters

Parameters

f	the face on which the normal is computed
pmesh	the polygon mesh containing f
np	optional sequence of Named Parameters among the ones listed below

Named Parameters

vertex_point_map	the property map with the points associated to the vertices of pmesh. If this parameter is omitted, an internal property map for CGAL::vertex_point_t must be available in PolygonMesh
geom_traits	an instance of a geometric traits class, model of Kernel

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 Kernel::FT does not have a sqrt() operation, the square root computation will be done approximately.

compute_face_normals()

template<typename PolygonMesh , typename FaceNormalMap , typename NamedParameters >

void CGAL::Polygon_mesh_processing::compute_face_normals	(	const PolygonMesh &	pmesh,
		FaceNormalMap	fnm,
		const NamedParameters &	np
	)

#include <CGAL/Polygon_mesh_processing/compute_normal.h>

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

Template Parameters

PolygonMesh	a model of FaceGraph
FaceNormalMap	a model of WritablePropertyMap with boost::graph_traits<PolygonMesh>::face_descriptor as key type and Kernel::Vector_3 as value type.

Parameters

pmesh	the polygon mesh
fnm	the property map in which the normals are written
np	optional sequence of Named Parameters among the ones listed below

Named Parameters

vertex_point_map	the property map with the points associated to the vertices of pmesh. If this parameter is omitted, an internal property map for CGAL::vertex_point_t must be available in PolygonMesh
geom_traits	an instance of a geometric traits class, model of Kernel

Warning

This function involves a square root computation. If Kernel::FT does not have a sqrt() operation, the square root computation will be done approximately.

compute_normals()

template<typename PolygonMesh , typename VertexNormalMap , typename FaceNormalMap , typename NamedParameters >

void CGAL::Polygon_mesh_processing::compute_normals	(	const PolygonMesh &	pmesh,
		VertexNormalMap	vnm,
		FaceNormalMap	fnm,
		const NamedParameters &	np
	)

#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

PolygonMesh	a model of FaceListGraph
VertexNormalMap	a model of WritablePropertyMap with boost::graph_traits<PolygonMesh>::vertex_descriptor as key type and Kernel::Vector_3 as value type.
FaceNormalMap	a model of ReadWritePropertyMap with boost::graph_traits<PolygonMesh>::face_descriptor as key type and Kernel::Vector_3 as value type.

Parameters

pmesh	the polygon mesh
vnm	the property map in which the vertex normals are written
fnm	the property map in which the face normals are written
np	optional sequence of Named Parameters among the ones listed below

Named Parameters

vertex_point_map	the property map with the points associated to the vertices of pmesh. If this parameter is omitted, an internal property map for CGAL::vertex_point_t must be available in PolygonMesh
geom_traits	an instance of a geometric traits class, model of Kernel

Warning

This function involves a square root computation. If Kernel::FT does not have a sqrt() operation, the square root computation will be done approximately.

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 >

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

#include <CGAL/Polygon_mesh_processing/compute_normal.h>

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

Template Parameters

PolygonMesh

a model of FaceGraph

Parameters

v	the vertex at which the normal is computed
pmesh	the polygon mesh containing v
np	optional sequence of Named Parameters among the ones listed below

Named Parameters

vertex_point_map	the property map with the points associated to the vertices of pmesh. If this parameter is omitted, an internal property map for CGAL::vertex_point_t must be available in PolygonMesh
geom_traits	an instance of a geometric traits class, model of Kernel

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 Kernel::FT does not have a sqrt() operation, the square root computation will be done approximately.

compute_vertex_normals()

template<typename PolygonMesh , typename VertexNormalMap , typename NamedParameters >

void CGAL::Polygon_mesh_processing::compute_vertex_normals	(	const PolygonMesh &	pmesh,
		VertexNormalMap	vnm,
		const NamedParameters &	np
	)

#include <CGAL/Polygon_mesh_processing/compute_normal.h>

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

Template Parameters

PolygonMesh	a model of FaceListGraph
VertexNormalMap	a 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

pmesh	the polygon mesh
vnm	the property map in which the normals are written
np	optional sequence of Named Parameters among the ones listed below

Named Parameters

vertex_point_map	the property map with the points associated to the vertices of pmesh. If this parameter is omitted, an internal property map for CGAL::vertex_point_t must be available in PolygonMesh
geom_traits	an instance of a geometric traits class, model of Kernel

Warning

This function involves a square root computation. If Kernel::FT does not have a sqrt() operation, the square root computation will be done approximately.