Open CASCADE Technology  6.9.0
Public Member Functions | Static Public Member Functions

Geom_BezierCurve Class Reference

Describes a rational or non-rational Bezier curve. More...

#include <Geom_BezierCurve.hxx>

Inheritance diagram for Geom_BezierCurve:
Inheritance graph
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Public Member Functions

 Geom_BezierCurve (const TColgp_Array1OfPnt &CurvePoles)
 Creates a non rational Bezier curve with a set of poles CurvePoles. The weights are defaulted to all being 1. Raises ConstructionError if the number of poles is greater than MaxDegree + 1 or lower than 2. More...
 
 Geom_BezierCurve (const TColgp_Array1OfPnt &CurvePoles, const TColStd_Array1OfReal &PoleWeights)
 Creates a rational Bezier curve with the set of poles CurvePoles and the set of weights PoleWeights . If all the weights are identical the curve is considered as non rational. Raises ConstructionError if the number of poles is greater than MaxDegree + 1 or lower than 2 or CurvePoles and CurveWeights have not the same length or one weight value is lower or equal to Resolution from package gp. More...
 
void Increase (const Standard_Integer Degree)
 Increases the degree of a bezier curve. Degree is the new degree of <me>. Raises ConstructionError if Degree is greater than MaxDegree or lower than 2 or lower than the initial degree of <me>. More...
 
void InsertPoleAfter (const Standard_Integer Index, const gp_Pnt &P)
 Inserts a pole P after the pole of range Index. If the curve <me> is rational the weight value for the new pole of range Index is 1.0. raised if Index is not in the range [1, NbPoles]. More...
 
void InsertPoleAfter (const Standard_Integer Index, const gp_Pnt &P, const Standard_Real Weight)
 Inserts a pole with its weight in the set of poles after the pole of range Index. If the curve was non rational it can become rational if all the weights are not identical. Raised if Index is not in the range [1, NbPoles]. More...
 
void InsertPoleBefore (const Standard_Integer Index, const gp_Pnt &P)
 Inserts a pole P before the pole of range Index. If the curve <me> is rational the weight value for the new pole of range Index is 1.0. Raised if Index is not in the range [1, NbPoles]. More...
 
void InsertPoleBefore (const Standard_Integer Index, const gp_Pnt &P, const Standard_Real Weight)
 Inserts a pole with its weight in the set of poles after the pole of range Index. If the curve was non rational it can become rational if all the weights are not identical. Raised if Index is not in the range [1, NbPoles]. More...
 
void RemovePole (const Standard_Integer Index)
 Removes the pole of range Index. If the curve was rational it can become non rational. Raised if Index is not in the range [1, NbPoles] Raised if Degree is lower than 2. More...
 
void Reverse ()
 Reverses the direction of parametrization of <me> Value (NewU) = Value (1 - OldU) More...
 
Standard_Real ReversedParameter (const Standard_Real U) const
 Returns the parameter on the reversed curve for the point of parameter U on <me>. More...
 
void Segment (const Standard_Real U1, const Standard_Real U2)
 Segments the curve between U1 and U2 which can be out of the bounds of the curve. The curve is oriented from U1 to U2. The control points are modified, the first and the last point are not the same but the parametrization range is [0, 1] else it could not be a Bezier curve. Warnings : Even if <me> is not closed it can become closed after the segmentation for example if U1 or U2 are out of the bounds of the curve <me> or if the curve makes loop. After the segmentation the length of a curve can be null. More...
 
void SetPole (const Standard_Integer Index, const gp_Pnt &P)
 Substitutes the pole of range index with P. If the curve <me> is rational the weight of range Index is not modified. raiseD if Index is not in the range [1, NbPoles]. More...
 
void SetPole (const Standard_Integer Index, const gp_Pnt &P, const Standard_Real Weight)
 Substitutes the pole and the weights of range Index. If the curve <me> is not rational it can become rational if all the weights are not identical. If the curve was rational it can become non rational if all the weights are identical. Raised if Index is not in the range [1, NbPoles] Raised if Weight <= Resolution from package gp. More...
 
void SetWeight (const Standard_Integer Index, const Standard_Real Weight)
 Changes the weight of the pole of range Index. If the curve <me> is not rational it can become rational if all the weights are not identical. If the curve was rational it can become non rational if all the weights are identical. Raised if Index is not in the range [1, NbPoles] Raised if Weight <= Resolution from package gp. More...
 
Standard_Boolean IsClosed () const
 Returns True if the distance between the first point and the last point of the curve is lower or equal to the Resolution from package gp. More...
 
Standard_Boolean IsCN (const Standard_Integer N) const
 Continuity of the curve, returns True. More...
 
Standard_Boolean IsPeriodic () const
 Returns True if the parametrization of a curve is periodic. (P(u) = P(u + T) T = constante) More...
 
Standard_Boolean IsRational () const
 Returns false if all the weights are identical. The tolerance criterion is Resolution from package gp. More...
 
GeomAbs_Shape Continuity () const
 a Bezier curve is CN More...
 
Standard_Integer Degree () const
 Returns the polynomial degree of the curve. it is the number of poles - 1 point P and derivatives (V1, V2, V3) computation The Bezier Curve has a Polynomial representation so the parameter U can be out of the bounds of the curve. More...
 
void D0 (const Standard_Real U, gp_Pnt &P) const
 Returns in P the point of parameter U. 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. 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. Raised if the continuity of the curve is not C1. 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. Raised if the continuity of the curve is not C2. More...
 
void D3 (const Standard_Real U, gp_Pnt &P, gp_Vec &V1, gp_Vec &V2, gp_Vec &V3) const
 For this Bezier curve, computes. More...
 
gp_Vec DN (const Standard_Real U, const Standard_Integer N) const
 For the point of parameter U of this Bezier curve, computes the vector corresponding to the Nth derivative. Note: the parameter U can be outside the bounds of the curve. Exceptions Standard_RangeError if N is less than 1. More...
 
gp_Pnt StartPoint () const
 Returns Value (U=0.), it is the first control point of the curve. More...
 
gp_Pnt EndPoint () const
 Returns Value (U=1.), it is the last control point of the Bezier curve. More...
 
Standard_Real FirstParameter () const
 Returns the value of the first parameter of this Bezier curve. This is 0.0, which gives the start point of this Bezier curve. More...
 
Standard_Real LastParameter () const
 Returns the value of the last parameter of this Bezier curve. This is 1.0, which gives the end point of this Bezier curve. More...
 
Standard_Integer NbPoles () const
 Returns the number of poles of this Bezier curve. More...
 
gp_Pnt Pole (const Standard_Integer Index) const
 Returns the pole of range Index. Raised if Index is not in the range [1, NbPoles]. More...
 
void Poles (TColgp_Array1OfPnt &P) const
 Returns all the poles of the curve. More...
 
Standard_Real Weight (const Standard_Integer Index) const
 Returns the weight of range Index. Raised if Index is not in the range [1, NbPoles]. More...
 
void Weights (TColStd_Array1OfReal &W) const
 Returns all the weights of the curve. More...
 
void Transform (const gp_Trsf &T)
 Applies the transformation T to this Bezier curve. More...
 
void Resolution (const Standard_Real Tolerance3D, Standard_Real &UTolerance)
 Computes for this Bezier curve the parametric tolerance UTolerance for a given 3D tolerance Tolerance3D. If f(t) is the equation of this Bezier curve, UTolerance ensures that: |t1-t0| < UTolerance ===> |f(t1)-f(t0)| < Tolerance3D. More...
 
Handle< Geom_GeometryCopy () const
 Creates a new object which is a copy of this Bezier curve. More...
 
- Public Member Functions inherited from Geom_Curve
virtual Standard_Real TransformedParameter (const Standard_Real U, const gp_Trsf &T) const
 Returns the parameter on the transformed curve for the transform of the point of parameter U on <me>. More...
 
virtual Standard_Real ParametricTransformation (const gp_Trsf &T) const
 Returns a coefficient to compute the parameter on the transformed curve for the transform of the point on <me>. More...
 
Handle< Geom_CurveReversed () const
 Returns a copy of <me> reversed. More...
 
virtual Standard_Real Period () const
 Returns the period of this curve. 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>. 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. 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_GeometryMirrored (const gp_Pnt &P) const
 
Handle< Geom_GeometryMirrored (const gp_Ax1 &A1) const
 
Handle< Geom_GeometryMirrored (const gp_Ax2 &A2) const
 
Handle< Geom_GeometryRotated (const gp_Ax1 &A1, const Standard_Real Ang) const
 
Handle< Geom_GeometryScaled (const gp_Pnt &P, const Standard_Real S) const
 
Handle< Geom_GeometryTransformed (const gp_Trsf &T) const
 
Handle< Geom_GeometryTranslated (const gp_Vec &V) const
 
Handle< Geom_GeometryTranslated (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_Transientoperator= (const Standard_Transient &)
 Assignment operator, needed to avoid copying reference counter. More...
 
virtual ~Standard_Transient ()
 Destructor must be virtual. More...
 
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...
 

Static Public Member Functions

static Standard_Integer MaxDegree ()
 Returns the value of the maximum polynomial degree of any Geom_BezierCurve curve. This value is 25. More...
 

Detailed Description

Describes a rational or non-rational Bezier curve.

  1. However, the degree of a Geom_BezierCurve curve is limited to a value (25) which is defined and controlled by the system. This value is returned by the function MaxDegree. The parameter range for a Bezier curve is [ 0, 1 ]. If the first and last control points of the Bezier curve are the same point then the curve is closed. For example, to create a closed Bezier curve with four control points, you have to give the set of control points P1, P2, P3 and P1. The continuity of a Bezier curve is infinite. It is not possible to build a Bezier curve with negative weights. We consider that a weight value is zero if it is less than or equal to gp::Resolution(). We also consider that two weight values W1 and W2 are equal if: |W2 - W1| <= gp::Resolution(). Warning

Constructor & Destructor Documentation

Geom_BezierCurve::Geom_BezierCurve ( const TColgp_Array1OfPnt CurvePoles)

Creates a non rational Bezier curve with a set of poles CurvePoles. The weights are defaulted to all being 1. Raises ConstructionError if the number of poles is greater than MaxDegree + 1 or lower than 2.

Geom_BezierCurve::Geom_BezierCurve ( const TColgp_Array1OfPnt CurvePoles,
const TColStd_Array1OfReal PoleWeights 
)

Creates a rational Bezier curve with the set of poles CurvePoles and the set of weights PoleWeights . If all the weights are identical the curve is considered as non rational. Raises ConstructionError if the number of poles is greater than MaxDegree + 1 or lower than 2 or CurvePoles and CurveWeights have not the same length or one weight value is lower or equal to Resolution from package gp.

Member Function Documentation

GeomAbs_Shape Geom_BezierCurve::Continuity ( ) const
virtual

a Bezier curve is CN

Implements Geom_Curve.

Handle< Geom_Geometry > Geom_BezierCurve::Copy ( ) const
virtual

Creates a new object which is a copy of this Bezier curve.

Implements Geom_Geometry.

void Geom_BezierCurve::D0 ( const Standard_Real  U,
gp_Pnt P 
) const
virtual

Returns in P the point of parameter U. 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.

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.

Implements Geom_Curve.

void Geom_BezierCurve::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. Raised if the continuity of the curve is not C1.

Implements Geom_Curve.

void Geom_BezierCurve::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. Raised if the continuity of the curve is not C2.

Implements Geom_Curve.

void Geom_BezierCurve::D3 ( const Standard_Real  U,
gp_Pnt P,
gp_Vec V1,
gp_Vec V2,
gp_Vec V3 
) const
virtual

For this Bezier curve, computes.

  • the point P of parameter U, or
  • the point P and one or more of the following values:
  • V1, the first derivative vector,
  • V2, the second derivative vector,
  • V3, the third derivative vector. Note: the parameter U can be outside the bounds of the curve.

Implements Geom_Curve.

Standard_Integer Geom_BezierCurve::Degree ( ) const

Returns the polynomial degree of the curve. it is the number of poles - 1 point P and derivatives (V1, V2, V3) computation The Bezier Curve has a Polynomial representation so the parameter U can be out of the bounds of the curve.

gp_Vec Geom_BezierCurve::DN ( const Standard_Real  U,
const Standard_Integer  N 
) const
virtual

For the point of parameter U of this Bezier curve, computes the vector corresponding to the Nth derivative. Note: the parameter U can be outside the bounds of the curve. Exceptions Standard_RangeError if N is less than 1.

Implements Geom_Curve.

gp_Pnt Geom_BezierCurve::EndPoint ( ) const
virtual

Returns Value (U=1.), it is the last control point of the Bezier curve.

Implements Geom_BoundedCurve.

Standard_Real Geom_BezierCurve::FirstParameter ( ) const
virtual

Returns the value of the first parameter of this Bezier curve. This is 0.0, which gives the start point of this Bezier curve.

Implements Geom_Curve.

void Geom_BezierCurve::Increase ( const Standard_Integer  Degree)

Increases the degree of a bezier curve. Degree is the new degree of <me>. Raises ConstructionError if Degree is greater than MaxDegree or lower than 2 or lower than the initial degree of <me>.

void Geom_BezierCurve::InsertPoleAfter ( const Standard_Integer  Index,
const gp_Pnt P 
)

Inserts a pole P after the pole of range Index. If the curve <me> is rational the weight value for the new pole of range Index is 1.0. raised if Index is not in the range [1, NbPoles].

raised if the resulting number of poles is greater than MaxDegree + 1.

void Geom_BezierCurve::InsertPoleAfter ( const Standard_Integer  Index,
const gp_Pnt P,
const Standard_Real  Weight 
)

Inserts a pole with its weight in the set of poles after the pole of range Index. If the curve was non rational it can become rational if all the weights are not identical. Raised if Index is not in the range [1, NbPoles].

Raised if the resulting number of poles is greater than MaxDegree + 1. Raised if Weight is lower or equal to Resolution from package gp.

void Geom_BezierCurve::InsertPoleBefore ( const Standard_Integer  Index,
const gp_Pnt P 
)

Inserts a pole P before the pole of range Index. If the curve <me> is rational the weight value for the new pole of range Index is 1.0. Raised if Index is not in the range [1, NbPoles].

Raised if the resulting number of poles is greater than MaxDegree + 1.

void Geom_BezierCurve::InsertPoleBefore ( const Standard_Integer  Index,
const gp_Pnt P,
const Standard_Real  Weight 
)

Inserts a pole with its weight in the set of poles after the pole of range Index. If the curve was non rational it can become rational if all the weights are not identical. Raised if Index is not in the range [1, NbPoles].

Raised if the resulting number of poles is greater than MaxDegree + 1. Raised if Weight is lower or equal to Resolution from package gp.

Standard_Boolean Geom_BezierCurve::IsClosed ( ) const
virtual

Returns True if the distance between the first point and the last point of the curve is lower or equal to the Resolution from package gp.

Implements Geom_Curve.

Standard_Boolean Geom_BezierCurve::IsCN ( const Standard_Integer  N) const
virtual

Continuity of the curve, returns True.

Implements Geom_Curve.

Standard_Boolean Geom_BezierCurve::IsPeriodic ( ) const
virtual

Returns True if the parametrization of a curve is periodic. (P(u) = P(u + T) T = constante)

Implements Geom_Curve.

Standard_Boolean Geom_BezierCurve::IsRational ( ) const

Returns false if all the weights are identical. The tolerance criterion is Resolution from package gp.

Standard_Real Geom_BezierCurve::LastParameter ( ) const
virtual

Returns the value of the last parameter of this Bezier curve. This is 1.0, which gives the end point of this Bezier curve.

Implements Geom_Curve.

static Standard_Integer Geom_BezierCurve::MaxDegree ( )
static

Returns the value of the maximum polynomial degree of any Geom_BezierCurve curve. This value is 25.

Standard_Integer Geom_BezierCurve::NbPoles ( ) const

Returns the number of poles of this Bezier curve.

gp_Pnt Geom_BezierCurve::Pole ( const Standard_Integer  Index) const

Returns the pole of range Index. Raised if Index is not in the range [1, NbPoles].

void Geom_BezierCurve::Poles ( TColgp_Array1OfPnt P) const

Returns all the poles of the curve.

Raised if the length of P is not equal to the number of poles.

void Geom_BezierCurve::RemovePole ( const Standard_Integer  Index)

Removes the pole of range Index. If the curve was rational it can become non rational. Raised if Index is not in the range [1, NbPoles] Raised if Degree is lower than 2.

void Geom_BezierCurve::Resolution ( const Standard_Real  Tolerance3D,
Standard_Real UTolerance 
)

Computes for this Bezier curve the parametric tolerance UTolerance for a given 3D tolerance Tolerance3D. If f(t) is the equation of this Bezier curve, UTolerance ensures that: |t1-t0| < UTolerance ===> |f(t1)-f(t0)| < Tolerance3D.

void Geom_BezierCurve::Reverse ( )
virtual

Reverses the direction of parametrization of <me> Value (NewU) = Value (1 - OldU)

Implements Geom_Curve.

Standard_Real Geom_BezierCurve::ReversedParameter ( const Standard_Real  U) const
virtual

Returns the parameter on the reversed curve for the point of parameter U on <me>.

returns 1-U

Implements Geom_Curve.

void Geom_BezierCurve::Segment ( const Standard_Real  U1,
const Standard_Real  U2 
)

Segments the curve between U1 and U2 which can be out of the bounds of the curve. The curve is oriented from U1 to U2. The control points are modified, the first and the last point are not the same but the parametrization range is [0, 1] else it could not be a Bezier curve. Warnings : Even if <me> is not closed it can become closed after the segmentation for example if U1 or U2 are out of the bounds of the curve <me> or if the curve makes loop. After the segmentation the length of a curve can be null.

void Geom_BezierCurve::SetPole ( const Standard_Integer  Index,
const gp_Pnt P 
)

Substitutes the pole of range index with P. If the curve <me> is rational the weight of range Index is not modified. raiseD if Index is not in the range [1, NbPoles].

void Geom_BezierCurve::SetPole ( const Standard_Integer  Index,
const gp_Pnt P,
const Standard_Real  Weight 
)

Substitutes the pole and the weights of range Index. If the curve <me> is not rational it can become rational if all the weights are not identical. If the curve was rational it can become non rational if all the weights are identical. Raised if Index is not in the range [1, NbPoles] Raised if Weight <= Resolution from package gp.

void Geom_BezierCurve::SetWeight ( const Standard_Integer  Index,
const Standard_Real  Weight 
)

Changes the weight of the pole of range Index. If the curve <me> is not rational it can become rational if all the weights are not identical. If the curve was rational it can become non rational if all the weights are identical. Raised if Index is not in the range [1, NbPoles] Raised if Weight <= Resolution from package gp.

gp_Pnt Geom_BezierCurve::StartPoint ( ) const
virtual

Returns Value (U=0.), it is the first control point of the curve.

Implements Geom_BoundedCurve.

void Geom_BezierCurve::Transform ( const gp_Trsf T)
virtual

Applies the transformation T to this Bezier curve.

Implements Geom_Geometry.

Standard_Real Geom_BezierCurve::Weight ( const Standard_Integer  Index) const

Returns the weight of range Index. Raised if Index is not in the range [1, NbPoles].

void Geom_BezierCurve::Weights ( TColStd_Array1OfReal W) const

Returns all the weights of the curve.

Raised if the length of W is not equal to the number of poles.


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