GProp_PGProps Class Reference

Computes global properties (mass, barycentre, inertia matrix) of a weighted set of 3D points. More...

#include <GProp_PGProps.hxx>

Inheritance diagram for GProp_PGProps:

Public Member Functions
	GProp_PGProps ()
	Creates an empty point set, located at the origin, with zero mass.
	GProp_PGProps (const NCollection_Array1< gp_Pnt > &thePnts)
	Creates a point set from an array of points (unit mass each).
	GProp_PGProps (const NCollection_Array2< gp_Pnt > &thePnts)
	Creates a point set from a 2D array of points (unit mass each).
	GProp_PGProps (const NCollection_Array1< gp_Pnt > &thePnts, const NCollection_Array1< double > &theDensity)
	Creates a point set from points and corresponding densities.
	GProp_PGProps (const NCollection_Array2< gp_Pnt > &thePnts, const NCollection_Array2< double > &theDensity)
	Creates a point set from 2D arrays of points and corresponding densities.
void	AddPoint (const gp_Pnt &thePnt)
	Adds a point with unit mass.
void	AddPoint (const gp_Pnt &thePnt, double theDensity)
	Adds a point with a given mass.
Public Member Functions inherited from GProp_GProps
	GProp_GProps ()
	The origin (0, 0, 0) of the absolute Cartesian coordinate system is used to compute the global properties.
	GProp_GProps (const gp_Pnt &SystemLocation)
	The point SystemLocation is used to compute the global properties of the system. For greater accuracy, define this point close to the location of the system; for example a point near the centre of mass of the system.
void	Add (const GProp_GProps &Item, const double Density=1.0)
	Either:
double	Mass () const
	Returns the mass of the current system.
gp_Pnt	CentreOfMass () const
	Returns the centre of mass of the current system. With a uniform gravitational field this is also the centre of gravity. The coordinates returned for the centre of mass are expressed in the absolute Cartesian coordinate system.
gp_Mat	MatrixOfInertia () const
	Returns the matrix of inertia. It is a symmetric matrix whose coefficients are the quadratic moments of inertia:
void	StaticMoments (double &Ix, double &Iy, double &Iz) const
	Returns the static moments of inertia of the current system - i.e. the moments of inertia about the three axes of the absolute Cartesian coordinate system.
double	MomentOfInertia (const gp_Ax1 &A) const
	Computes the moment of inertia of the system about the axis A.
GProp_PrincipalProps	PrincipalProperties () const
	Computes the principal properties of inertia of the current system. There is always a set of axes for which the products of inertia of a geometric system are equal to 0 - i.e. the matrix of inertia of the system is diagonal. These axes are the principal axes of inertia; their origin coincides with the centre of mass of the system. The associated moments are called the principal moments of inertia.
double	RadiusOfGyration (const gp_Ax1 &A) const
	Returns the radius of gyration of the current system about the axis A.

Static Public Member Functions
static gp_Pnt	Barycentre (const NCollection_Array1< gp_Pnt > &thePnts)
	Computes the barycentre of a set of points (unit mass).
static gp_Pnt	Barycentre (const NCollection_Array2< gp_Pnt > &thePnts)
	Computes the barycentre of a 2D array of points (unit mass).
static void	Barycentre (const NCollection_Array1< gp_Pnt > &thePnts, const NCollection_Array1< double > &theDensity, double &theMass, gp_Pnt &theG)
	Computes the weighted barycentre and total mass of a set of points.
static void	Barycentre (const NCollection_Array2< gp_Pnt > &thePnts, const NCollection_Array2< double > &theDensity, double &theMass, gp_Pnt &theG)
	Computes the weighted barycentre and total mass for a 2D point array.

Additional Inherited Members
Protected Attributes inherited from GProp_GProps
gp_Pnt	g
	Centre of mass (absolute frame)
gp_Pnt	loc
	Reference point used for inertia accumulation.
double	dim
	Total mass / length / area / volume.
gp_Mat	inertia
	Quadratic moments of inertia matrix.

Detailed Description

Computes global properties (mass, barycentre, inertia matrix) of a weighted set of 3D points.

Each point carries a mass; by default the mass is unit. Contributions are accumulated incrementally via AddPoint() or from arrays passed to a constructor. As a GProp_GProps subclass, an instance can be composed into a larger system via GProp_GProps::Add().

Inertia is accumulated at the absolute origin and stored in the inherited GProp_GProps::inertia member, matching the legacy contract of this class.

Constructor & Destructor Documentation

GProp_PGProps() [1/5]

GProp_PGProps::GProp_PGProps

(

)

Creates an empty point set, located at the origin, with zero mass.

GProp_PGProps() [2/5]

GProp_PGProps::GProp_PGProps ( const NCollection_Array1< gp_Pnt > & thePnts )

explicit

Creates a point set from an array of points (unit mass each).

GProp_PGProps() [3/5]

GProp_PGProps::GProp_PGProps ( const NCollection_Array2< gp_Pnt > & thePnts )

explicit

Creates a point set from a 2D array of points (unit mass each).

GProp_PGProps() [4/5]

GProp_PGProps::GProp_PGProps	(	const NCollection_Array1< gp_Pnt > &	thePnts,
		const NCollection_Array1< double > &	theDensity )

Creates a point set from points and corresponding densities.

Parameters

[in]	thePnts	point array
[in]	theDensity	per-point mass array (same length as thePnts)

Exceptions

Standard_DomainError

if a density <= gp::Resolution() or if the arrays have different lengths.

GProp_PGProps() [5/5]

GProp_PGProps::GProp_PGProps	(	const NCollection_Array2< gp_Pnt > &	thePnts,
		const NCollection_Array2< double > &	theDensity )

Creates a point set from 2D arrays of points and corresponding densities.

Parameters

[in]	thePnts	point array
[in]	theDensity	per-point mass array (same dimensions as thePnts)

Exceptions

Standard_DomainError

on dimension mismatch or non-positive density.

Member Function Documentation

AddPoint() [1/2]

void GProp_PGProps::AddPoint

(

const gp_Pnt &

thePnt

)

Adds a point with unit mass.

AddPoint() [2/2]

void GProp_PGProps::AddPoint	(	const gp_Pnt &	thePnt,
		double	theDensity )

Adds a point with a given mass.

Exceptions

Standard_DomainError

if theDensity <= gp::Resolution().

Barycentre() [1/4]

static gp_Pnt GProp_PGProps::Barycentre ( const NCollection_Array1< gp_Pnt > & thePnts )

static

Computes the barycentre of a set of points (unit mass).

Barycentre() [2/4]

static void GProp_PGProps::Barycentre ( const NCollection_Array1< gp_Pnt > & thePnts, const NCollection_Array1< double > & theDensity, double & theMass, gp_Pnt & theG )

static

Computes the weighted barycentre and total mass of a set of points.

Parameters

[in]	thePnts	point array
[in]	theDensity	per-point mass array
[out]	theMass	total mass (sum of densities)
[out]	theG	weighted barycentre

Exceptions

Standard_DimensionError

on length mismatch.

Barycentre() [3/4]

static gp_Pnt GProp_PGProps::Barycentre ( const NCollection_Array2< gp_Pnt > & thePnts )

static

Computes the barycentre of a 2D array of points (unit mass).

Barycentre() [4/4]

static void GProp_PGProps::Barycentre ( const NCollection_Array2< gp_Pnt > & thePnts, const NCollection_Array2< double > & theDensity, double & theMass, gp_Pnt & theG )

static

Computes the weighted barycentre and total mass for a 2D point array.

Exceptions

Standard_DimensionError

on dimension mismatch.

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The documentation for this class was generated from the following file:

• GProp_PGProps.hxx