Describes a parabola in 3D space.
A parabola is defined by its focal length (i.e. the
distance between its focus and its apex) and is
positioned in space with a coordinate system
(gp_Ax2 object) where:
More...

#include <Geom_Parabola.hxx>

Inheritance diagram for Geom_Parabola:

[legend]

Public Member Functions
	Geom_Parabola (const gp_Parab &Prb)
	Creates a parabola from a non transient one. More...

	Geom_Parabola (const gp_Ax2 &A2, const Standard_Real Focal)
	Creates a parabola with its local coordinate system "A2" and it's focal length "Focal". The XDirection of A2 defines the axis of symmetry of the parabola. The YDirection of A2 is parallel to the directrix of the parabola. The Location point of A2 is the vertex of the parabola //! Raised if Focal < 0.0 More...

	Geom_Parabola (const gp_Ax1 &D, const gp_Pnt &F)
	D is the directrix of the parabola and F the focus point. The symmetry axis (XAxis) of the parabola is normal to the directrix and pass through the focus point F, but its location point is the vertex of the parabola. The YAxis of the parabola is parallel to D and its location point is the vertex of the parabola. The normal to the plane of the parabola is the cross product between the XAxis and the YAxis. More...

void	SetFocal (const Standard_Real Focal)
	Assigns the value Focal to the focal distance of this parabola. <br> Exceptions Standard_ConstructionError if Focal is negative. More...

void	SetParab (const gp_Parab &Prb)
	Converts the gp_Parab parabola Prb into this parabola. More...

gp_Parab	Parab () const
	Returns the non transient parabola from gp with the same geometric properties as <me>. More...

Standard_Real	ReversedParameter (const Standard_Real U) const
	Computes the parameter on the reversed parabola, <br> for the point of parameter U on this parabola. For a parabola, the returned value is: -U. More...

Standard_Real	FirstParameter () const
	Returns the value of the first or last parameter of this <br> parabola. This is, respectively: More...

Standard_Real	LastParameter () const
	Returns the value of the first or last parameter of this <br> parabola. This is, respectively: More...

Standard_Boolean	IsClosed () const
	Returns False More...

Standard_Boolean	IsPeriodic () const
	Returns False More...

gp_Ax1	Directrix () const
	Computes the directrix of this parabola. <br> This is a line normal to the axis of symmetry, in the plane of this parabola, located on the negative side of its axis of symmetry, at a distance from the apex equal to the focal length. The directrix is returned as an axis (gp_Ax1 object), where the origin is located on the "X Axis" of this parabola. More...

Standard_Real	Eccentricity () const
	Returns 1. (which is the eccentricity of any parabola). More...

gp_Pnt	Focus () const
	Computes the focus of this parabola. The focus is on the <br> positive side of the "X Axis" of the local coordinate system of the parabola. More...

Standard_Real	Focal () const
	Computes the focal distance of this parabola <br> The focal distance is the distance between the apex and the focus of the parabola. More...

Standard_Real	Parameter () const
	Computes the parameter of this parabola which is the <br> distance between its focus and its directrix. This distance is twice the focal length. If P is the parameter of the parabola, the equation of the parabola in its local coordinate system is: Y*2 = 2.P*X. More...

void	D0 (const Standard_Real U, gp_Pnt &P) const
	Returns in P the point of parameter U. <br> If U = 0 the returned point is the origin of the XAxis and the YAxis of the parabola and it is the vertex of the parabola. P = S + F * (U * U * XDir + * U * YDir) where S is the vertex of the parabola, XDir the XDirection and YDir the YDirection of the parabola's local coordinate system. More...

void	D1 (const Standard_Real U, gp_Pnt &P, gp_Vec &V1) const
	Returns the point P of parameter U and the first derivative V1. More...

void	D2 (const Standard_Real U, gp_Pnt &P, gp_Vec &V1, gp_Vec &V2) const
	Returns the point P of parameter U, the first and second derivatives V1 and V2. More...

void	D3 (const Standard_Real U, gp_Pnt &P, gp_Vec &V1, gp_Vec &V2, gp_Vec &V3) const
	Returns the point P of parameter U, the first second and third derivatives V1 V2 and V3. More...

gp_Vec	DN (const Standard_Real U, const Standard_Integer N) const
	For the point of parameter U of this parabola, <br> computes the vector corresponding to the Nth derivative. Exceptions Standard_RangeError if N is less than 1. More...

void	Transform (const gp_Trsf &T)
	Applies the transformation T to this parabola. More...

Standard_Real	TransformedParameter (const Standard_Real U, const gp_Trsf &T) const
	Returns the parameter on the transformed curve for <br> the transform of the point of parameter U on <me>. <br> me->Transformed(T)->Value(me->TransformedParameter(U,T)) is the same point as me->Value(U).Transformed(T) This methods returns <U> * T.ScaleFactor() More...

Standard_Real	ParametricTransformation (const gp_Trsf &T) const
	Returns a coefficient to compute the parameter on <br> the transformed curve for the transform of the <br> point on <me>. <br> Transformed(T)->Value(U * ParametricTransformation(T)) is the same point as Value(U).Transformed(T) This methods returns T.ScaleFactor() More...

Handle_Geom_Geometry	Copy () const
	Creates a new object which is a copy of this parabola. More...

Public Member Functions inherited from Geom_Conic
void	SetAxis (const gp_Ax1 &A1)
	Changes the orientation of the conic's plane. The normal <br> axis to the plane is A1. The XAxis and the YAxis are recomputed. raised if the A1 is parallel to the XAxis of the conic. More...

void	SetLocation (const gp_Pnt &P)
	changes the location point of the conic. More...

void	SetPosition (const gp_Ax2 &A2)
	changes the local coordinate system of the conic. More...

gp_Ax1	Axis () const
	Returns the "main Axis" of this conic. This axis is <br> normal to the plane of the conic. More...

gp_Pnt	Location () const
	Returns the location point of the conic. For the circle, the ellipse and the hyperbola it is the center of the conic. For the parabola it is the Apex of the parabola. More...

const gp_Ax2 &	Position () const
	Returns the local coordinates system of the conic. The main direction of the Axis2Placement is normal to the plane of the conic. The X direction of the Axis2placement is in the plane of the conic and corresponds to the origin for the conic's parametric value u. More...

gp_Ax1	XAxis () const
	Returns the XAxis of the conic. This axis defines the origin of parametrization of the conic. This axis is perpendicular to the Axis of the conic. This axis and the Yaxis define the plane of the conic. More...

gp_Ax1	YAxis () const
	Returns the YAxis of the conic. The YAxis is perpendicular to the Xaxis. This axis and the Xaxis define the plane of the conic. More...

void	Reverse ()
	Reverses the direction of parameterization of <me>. The local coordinate system of the conic is modified. More...

GeomAbs_Shape	Continuity () const
	The continuity of the conic is Cn. More...

Standard_Boolean	IsCN (const Standard_Integer N) const
	Returns True. //! Raised if N < 0. More...

Public Member Functions inherited from Geom_Curve
Handle_Geom_Curve	Reversed () const
	Returns a copy of <me> reversed. More...

virtual Standard_Real	Period () const
	Returns the period of this curve. <br> Exceptions Standard_NoSuchObject if this curve is not periodic. More...

gp_Pnt	Value (const Standard_Real U) const
	Computes the point of parameter U on <me>. <br> If the curve is periodic then the returned point is P(U) with U = Ustart + (U - Uend) where Ustart and Uend are the parametric bounds of the curve. it is implemented with D0. Raised only for the "OffsetCurve" if it is not possible to compute the current point. For example when the first derivative on the basis curve and the offset direction are parallel. More...

Public Member Functions inherited from Geom_Geometry
void	Mirror (const gp_Pnt &P)
	Performs the symmetrical transformation of a Geometry with respect to the point P which is the center of the symmetry. More...

void	Mirror (const gp_Ax1 &A1)
	Performs the symmetrical transformation of a Geometry with respect to an axis placement which is the axis of the symmetry. More...

void	Mirror (const gp_Ax2 &A2)
	Performs the symmetrical transformation of a Geometry with respect to a plane. The axis placement A2 locates the plane of the symmetry : (Location, XDirection, YDirection). More...

void	Rotate (const gp_Ax1 &A1, const Standard_Real Ang)
	Rotates a Geometry. A1 is the axis of the rotation. Ang is the angular value of the rotation in radians. More...

void	Scale (const gp_Pnt &P, const Standard_Real S)
	Scales a Geometry. S is the scaling value. More...

void	Translate (const gp_Vec &V)
	Translates a Geometry. V is the vector of the tanslation. More...

void	Translate (const gp_Pnt &P1, const gp_Pnt &P2)
	Translates a Geometry from the point P1 to the point P2. More...

Handle_Geom_Geometry	Mirrored (const gp_Pnt &P) const

Handle_Geom_Geometry	Mirrored (const gp_Ax1 &A1) const

Handle_Geom_Geometry	Mirrored (const gp_Ax2 &A2) const

Handle_Geom_Geometry	Rotated (const gp_Ax1 &A1, const Standard_Real Ang) const

Handle_Geom_Geometry	Scaled (const gp_Pnt &P, const Standard_Real S) const

Handle_Geom_Geometry	Transformed (const gp_Trsf &T) const

Handle_Geom_Geometry	Translated (const gp_Vec &V) const

Handle_Geom_Geometry	Translated (const gp_Pnt &P1, const gp_Pnt &P2) const

Public Member Functions inherited from MMgt_TShared
virtual void	Delete () const
	Memory deallocator for transient classes. More...

Public Member Functions inherited from Standard_Transient
	Standard_Transient ()
	Empty constructor. More...

	Standard_Transient (const Standard_Transient &)
	Copy constructor – does nothing. More...

Standard_Transient &	operator= (const Standard_Transient &)
	Assignment operator, needed to avoid copying reference counter. More...

virtual	~Standard_Transient ()
	Destructor must be virtual. More...

virtual void	ShallowDump (Standard_OStream &) const

virtual const Handle_Standard_Type &	DynamicType () const
	Returns a type information object about this object. More...

Standard_Boolean	IsInstance (const Handle_Standard_Type &theType) const
	Returns a true value if this is an instance of Type. More...

Standard_Boolean	IsInstance (const Standard_CString theTypeName) const
	Returns a true value if this is an instance of TypeName. More...

Standard_Boolean	IsKind (const Handle_Standard_Type &theType) const
	Returns true if this is an instance of Type or an instance of any class that inherits from Type. Note that multiple inheritance is not supported by OCCT RTTI mechanism. More...

Standard_Boolean	IsKind (const Standard_CString theTypeName) const
	Returns true if this is an instance of TypeName or an instance of any class that inherits from TypeName. Note that multiple inheritance is not supported by OCCT RTTI mechanism. More...

virtual Handle_Standard_Transient	This () const
	Returns a Handle which references this object. Must never be called to objects created in stack. More...

Standard_Integer	GetRefCount () const
	Get the reference counter of this object. More...

Additional Inherited Members
Protected Attributes inherited from Geom_Conic
gp_Ax2	pos

Detailed Description

Describes a parabola in 3D space.
A parabola is defined by its focal length (i.e. the
distance between its focus and its apex) and is
positioned in space with a coordinate system
(gp_Ax2 object) where:

the origin is the apex of the parabola,
the "X Axis" defines the axis of symmetry; the
parabola is on the positive side of this axis,
the origin, "X Direction" and "Y Direction" define the
plane of the parabola.
This coordinate system is the local coordinate
system of the parabola.
The "main Direction" of this coordinate system is a
vector normal to the plane of the parabola. The axis,
of which the origin and unit vector are respectively the
origin and "main Direction" of the local coordinate
system, is termed the "Axis" or "main Axis" of the parabola.
The "main Direction" of the local coordinate system
gives an explicit orientation to the parabola,
determining the direction in which the parameter
increases along the parabola.
The Geom_Parabola parabola is parameterized as follows:
P(U) = O + U*U/(4.*F)*XDir + U*YDir
where:
P is the point of parameter U,
O, XDir and YDir are respectively the origin, "X <br> Direction" and "Y Direction" of its local coordinate system,
F is the focal length of the parabola.
The parameter of the parabola is therefore its Y
coordinate in the local coordinate system, with the "X <br> Axis" of the local coordinate system defining the origin
of the parameter.
The parameter range is ] -infinite, +infinite [.

Constructor & Destructor Documentation

Geom_Parabola::Geom_Parabola ( const gp_Parab & Prb )

Creates a parabola from a non transient one.

Geom_Parabola::Geom_Parabola	(	const gp_Ax2 &	A2,
		const Standard_Real	Focal
	)

Creates a parabola with its local coordinate system "A2"
and it's focal length "Focal".
The XDirection of A2 defines the axis of symmetry of the
parabola. The YDirection of A2 is parallel to the directrix
of the parabola. The Location point of A2 is the vertex of
the parabola
//! Raised if Focal < 0.0

Geom_Parabola::Geom_Parabola	(	const gp_Ax1 &	D,
		const gp_Pnt &	F
	)

D is the directrix of the parabola and F the focus point.
The symmetry axis (XAxis) of the parabola is normal to the
directrix and pass through the focus point F, but its
location point is the vertex of the parabola.
The YAxis of the parabola is parallel to D and its location
point is the vertex of the parabola. The normal to the plane
of the parabola is the cross product between the XAxis and the
YAxis.

Member Function Documentation

Handle_Geom_Geometry Geom_Parabola::Copy ( ) const

virtual

Creates a new object which is a copy of this parabola.

Implements Geom_Geometry.

void Geom_Parabola::D0	(	const Standard_Real	U,
		gp_Pnt &	P
	)		const

virtual

Returns in P the point of parameter U. <br>

If U = 0 the returned point is the origin of the XAxis and
the YAxis of the parabola and it is the vertex of the parabola.
P = S + F * (U * U * XDir + * U * YDir)
where S is the vertex of the parabola, XDir the XDirection and
YDir the YDirection of the parabola's local coordinate system.

Implements Geom_Curve.

void Geom_Parabola::D1	(	const Standard_Real	U,
		gp_Pnt &	P,
		gp_Vec &	V1
	)		const

virtual

Returns the point P of parameter U and the first derivative V1.

Implements Geom_Curve.

void Geom_Parabola::D2	(	const Standard_Real	U,
		gp_Pnt &	P,
		gp_Vec &	V1,
		gp_Vec &	V2
	)		const

virtual

Returns the point P of parameter U, the first and second
derivatives V1 and V2.

Implements Geom_Curve.

void Geom_Parabola::D3	(	const Standard_Real	U,
		gp_Pnt &	P,
		gp_Vec &	V1,
		gp_Vec &	V2,
		gp_Vec &	V3
	)		const

virtual

Returns the point P of parameter U, the first second and third
derivatives V1 V2 and V3.

Implements Geom_Curve.

gp_Ax1 Geom_Parabola::Directrix ( ) const

 Computes the directrix of this parabola. <br>

This is a line normal to the axis of symmetry, in the
plane of this parabola, located on the negative side
of its axis of symmetry, at a distance from the apex
equal to the focal length.
The directrix is returned as an axis (gp_Ax1 object),
where the origin is located on the "X Axis" of this parabola.

gp_Vec Geom_Parabola::DN	(	const Standard_Real	U,
		const Standard_Integer	N
	)		const

virtual

 For the point of parameter U of this parabola, <br>

computes the vector corresponding to the Nth derivative.
Exceptions Standard_RangeError if N is less than 1.

Implements Geom_Curve.

Standard_Real Geom_Parabola::Eccentricity ( ) const

virtual

Returns 1. (which is the eccentricity of any parabola).

Implements Geom_Conic.

Standard_Real Geom_Parabola::FirstParameter ( ) const

virtual

 Returns the value of the first or last parameter of this <br>

parabola. This is, respectively:

Standard_Real::RealFirst(), or
Standard_Real::RealLast().

Implements Geom_Curve.

Standard_Real Geom_Parabola::Focal ( ) const

 Computes the focal distance of this parabola <br>

The focal distance is the distance between the apex
and the focus of the parabola.

gp_Pnt Geom_Parabola::Focus ( ) const

 Computes the focus of this parabola. The focus is on the <br>

positive side of the "X Axis" of the local coordinate
system of the parabola.

Standard_Boolean Geom_Parabola::IsClosed ( ) const

virtual

Returns False

Implements Geom_Curve.

Standard_Boolean Geom_Parabola::IsPeriodic ( ) const

virtual

Returns False

Implements Geom_Curve.

Standard_Real Geom_Parabola::LastParameter ( ) const

virtual

 Returns the value of the first or last parameter of this <br>

parabola. This is, respectively:

Standard_Real::RealFirst(), or
Standard_Real::RealLast().

Implements Geom_Curve.

gp_Parab Geom_Parabola::Parab ( ) const

Returns the non transient parabola from gp with the same
geometric properties as <me>.

Standard_Real Geom_Parabola::Parameter ( ) const

 Computes the parameter of this parabola which is the <br>

distance between its focus and its directrix. This
distance is twice the focal length.
If P is the parameter of the parabola, the equation of
the parabola in its local coordinate system is: Y**2 = 2.*P*X.

Standard_Real Geom_Parabola::ParametricTransformation ( const gp_Trsf & T ) const

virtual

 Returns a  coefficient to compute the parameter on <br>
     the transformed  curve  for  the transform  of the <br>
     point on <me>. <br>

Transformed(T)->Value(U * ParametricTransformation(T))

is the same point as

Value(U).Transformed(T)

This methods returns T.ScaleFactor()

Reimplemented from Geom_Curve.

Standard_Real Geom_Parabola::ReversedParameter ( const Standard_Real U ) const

virtual

 Computes the parameter on the reversed parabola, <br>

for the point of parameter U on this parabola.
For a parabola, the returned value is: -U.

Implements Geom_Conic.

void Geom_Parabola::SetFocal ( const Standard_Real Focal )

 Assigns the value Focal to the focal distance of this parabola. <br>

Exceptions Standard_ConstructionError if Focal is negative.

void Geom_Parabola::SetParab ( const gp_Parab & Prb )

Converts the gp_Parab parabola Prb into this parabola.

void Geom_Parabola::Transform ( const gp_Trsf & T )

virtual

Applies the transformation T to this parabola.

Implements Geom_Geometry.

Standard_Real Geom_Parabola::TransformedParameter	(	const Standard_Real	U,
		const gp_Trsf &	T
	)		const

virtual

 Returns the  parameter on the  transformed  curve for <br>
     the transform of the point of parameter U on <me>. <br>

me->Transformed(T)->Value(me->TransformedParameter(U,T))

is the same point as

me->Value(U).Transformed(T)

This methods returns <U> * T.ScaleFactor()

Reimplemented from Geom_Curve.

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

Geom_Parabola.hxx

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation