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    Open CASCADE Technology Reference Manual 8.0.1
    Geom_Surface Class Referenceabstract

    Describes the common behavior of surfaces in 3D space. The Geom package provides many implementations of concrete derived surfaces, such as planes, cylinders, cones, spheres and tori, surfaces of linear extrusion, surfaces of revolution, Bezier and BSpline surfaces, and so on. The key characteristic of these surfaces is that they are parameterized. Geom_Surface demonstrates: More...

    #include <Geom_Surface.hxx>

    Inheritance diagram for Geom_Surface:

    Data Structures

    struct  ResD1
     Result of D1 evaluation: point and partial first derivatives. More...
    struct  ResD2
     Result of D2 evaluation: point and partial derivatives up to 2nd order. More...
    struct  ResD3
     Result of D3 evaluation: point and partial derivatives up to 3rd order. More...

    Public Member Functions

    virtual void UReverse ()=0
     Reverses the U direction of parametrization of <me>. The bounds of the surface are not modified.
    occ::handle< Geom_Surface > UReversed () const
     Reverses the U direction of parametrization of <me>. The bounds of the surface are not modified. A copy of <me> is returned.
    virtual double UReversedParameter (const double U) const =0
     Returns the parameter on the Ureversed surface for the point of parameter U on <me>.
    virtual void VReverse ()=0
     Reverses the V direction of parametrization of <me>. The bounds of the surface are not modified.
    occ::handle< Geom_Surface > VReversed () const
     Reverses the V direction of parametrization of <me>. The bounds of the surface are not modified. A copy of <me> is returned.
    virtual double VReversedParameter (const double V) const =0
     Returns the parameter on the Vreversed surface for the point of parameter V on <me>.
    virtual void TransformParameters (double &U, double &V, const gp_Trsf &T) const
     Computes the parameters on the transformed surface for the transform of the point of parameters U,V on <me>.
    virtual gp_GTrsf2d ParametricTransformation (const gp_Trsf &T) const
     Returns a 2d transformation used to find the new parameters of a point on the transformed surface.
    virtual void Bounds (double &U1, double &U2, double &V1, double &V2) const =0
     Returns the parametric bounds U1, U2, V1 and V2 of this surface. If the surface is infinite, this function can return a value equal to Precision::Infinite: instead of double::LastReal.
    virtual bool IsUClosed () const =0
     Checks whether this surface is closed in the u parametric direction. Returns true if, in the u parametric direction: taking uFirst and uLast as the parametric bounds in the u parametric direction, for each parameter v, the distance between the points P(uFirst, v) and P(uLast, v) is less than or equal to gp::Resolution().
    virtual bool IsVClosed () const =0
     Checks whether this surface is closed in the u parametric direction. Returns true if, in the v parametric direction: taking vFirst and vLast as the parametric bounds in the v parametric direction, for each parameter u, the distance between the points P(u, vFirst) and P(u, vLast) is less than or equal to gp::Resolution().
    virtual bool IsUPeriodic () const =0
     Checks if this surface is periodic in the u parametric direction. Returns true if:
    virtual double UPeriod () const
     Returns the period of this surface in the u parametric direction. Raises if the surface is not uperiodic.
    virtual bool IsVPeriodic () const =0
     Checks if this surface is periodic in the v parametric direction. Returns true if:
    virtual double VPeriod () const
     Returns the period of this surface in the v parametric direction. raises if the surface is not vperiodic.
    virtual occ::handle< Geom_Curve > UIso (const double U) const =0
     Computes the U isoparametric curve.
    virtual occ::handle< Geom_Curve > VIso (const double V) const =0
     Computes the V isoparametric curve.
    virtual GeomAbs_Shape Continuity () const =0
     Returns the Global Continuity of the surface in direction U and V :
    virtual bool IsCNu (const int N) const =0
     Returns the order of continuity of the surface in the U parametric direction. Raised if N < 0.
    virtual bool IsCNv (const int N) const =0
     Returns the order of continuity of the surface in the V parametric direction. Raised if N < 0.
    virtual gp_Pnt EvalD0 (const double U, const double V) const =0
     Computes the point of parameter (U, V) on the surface. Raises an exception on failure.
    virtual ResD1 EvalD1 (const double U, const double V) const =0
     Computes the point and first partial derivatives at (U, V). Raises an exception if the surface continuity is not C1.
    virtual ResD2 EvalD2 (const double U, const double V) const =0
     Computes the point and partial derivatives up to 2nd order at (U, V). Raises an exception if the surface continuity is not C2.
    virtual ResD3 EvalD3 (const double U, const double V) const =0
     Computes the point and partial derivatives up to 3rd order at (U, V). Raises an exception if the surface continuity is not C3.
    virtual gp_Vec EvalDN (const double U, const double V, const int Nu, const int Nv) const =0
     Computes the derivative of order Nu in U and Nv in V at the point (U, V). Raises an exception on failure.
    void D0 (const double U, const double V, gp_Pnt &P) const
     Computes the point of parameter (U, V).
    void D1 (const double U, const double V, gp_Pnt &P, gp_Vec &D1U, gp_Vec &D1V) const
     Computes the point and first partial derivatives.
    void D2 (const double U, const double V, gp_Pnt &P, gp_Vec &D1U, gp_Vec &D1V, gp_Vec &D2U, gp_Vec &D2V, gp_Vec &D2UV) const
     Computes the point and partial derivatives up to 2nd order.
    void D3 (const double U, const double V, gp_Pnt &P, gp_Vec &D1U, gp_Vec &D1V, gp_Vec &D2U, gp_Vec &D2V, gp_Vec &D2UV, gp_Vec &D3U, gp_Vec &D3V, gp_Vec &D3UUV, gp_Vec &D3UVV) const
     Computes the point and partial derivatives up to 3rd order.
    gp_Vec DN (const double U, const double V, const int Nu, const int Nv) const
     Computes the derivative of order Nu in U and Nv in V.
    gp_Pnt Value (const double U, const double V) const
     Computes the point of parameter (U, V) on the surface.
    void DumpJson (Standard_OStream &theOStream, int theDepth=-1) const override
     Dumps the content of me into the stream.
    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.
    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.
    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).
    void Rotate (const gp_Ax1 &A1, const double Ang)
     Rotates a Geometry. A1 is the axis of the rotation. Ang is the angular value of the rotation in radians.
    void Scale (const gp_Pnt &P, const double S)
     Scales a Geometry. S is the scaling value.
    void Translate (const gp_Vec &V)
     Translates a Geometry. V is the vector of the translation.
    void Translate (const gp_Pnt &P1, const gp_Pnt &P2)
     Translates a Geometry from the point P1 to the point P2.
    virtual void Transform (const gp_Trsf &T)=0
     Transformation of a geometric object. This transformation can be a translation, a rotation, a symmetry, a scaling or a complex transformation obtained by combination of the previous elementaries transformations. (see class Transformation of the package Geom).
    occ::handle< Geom_Geometry > Mirrored (const gp_Pnt &P) const
    occ::handle< Geom_Geometry > Mirrored (const gp_Ax1 &A1) const
    occ::handle< Geom_Geometry > Mirrored (const gp_Ax2 &A2) const
    occ::handle< Geom_Geometry > Rotated (const gp_Ax1 &A1, const double Ang) const
    occ::handle< Geom_Geometry > Scaled (const gp_Pnt &P, const double S) const
    occ::handle< Geom_Geometry > Transformed (const gp_Trsf &T) const
    occ::handle< Geom_Geometry > Translated (const gp_Vec &V) const
    occ::handle< Geom_Geometry > Translated (const gp_Pnt &P1, const gp_Pnt &P2) const
    virtual occ::handle< Geom_Geometry > Copy () const =0
     Creates a new object which is a copy of this geometric object.
    Public Member Functions inherited from Standard_Transient
     Standard_Transient ()
     Empty constructor.
     Standard_Transient (const Standard_Transient &)
     Copy constructor – does nothing.
    Standard_Transient & operator= (const Standard_Transient &)
     Assignment operator, needed to avoid copying reference counter.
    virtual ~Standard_Transient ()=default
     Destructor must be virtual.
    virtual const opencascade::handle< Standard_Type > & DynamicType () const
     Returns a type descriptor about this object.
    bool IsInstance (const opencascade::handle< Standard_Type > &theType) const
     Returns a true value if this is an instance of Type.
    bool IsInstance (const char *const theTypeName) const
     Returns a true value if this is an instance of TypeName.
    bool IsKind (const opencascade::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.
    bool IsKind (const char *const 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.
    Standard_Transient * This () const
     Returns non-const pointer to this object (like const_cast). For protection against creating handle to objects allocated in stack or call from constructor, it will raise exception Standard_ProgramError if reference counter is zero.
    int GetRefCount () const noexcept
     Get the reference counter of this object.
    void IncrementRefCounter () noexcept
     Increments the reference counter of this object. Uses relaxed memory ordering since incrementing only requires atomicity, not synchronization with other memory operations.
    int DecrementRefCounter () noexcept
     Decrements the reference counter of this object; returns the decremented value. Uses release ordering for the decrement to ensure all writes to the object are visible before the count reaches zero. An acquire fence is added only when the count reaches zero, ensuring proper synchronization before deletion. This is more efficient than using acq_rel for every decrement.
    virtual void Delete () const
     Memory deallocator for transient classes.

    Additional Inherited Members

    typedef void base_type
     Returns a type descriptor about this object.
    static constexpr const char * get_type_name ()
     Returns a type descriptor about this object.
    static const opencascade::handle< Standard_Type > & get_type_descriptor ()
     Returns type descriptor of Standard_Transient class.

    Detailed Description

    Describes the common behavior of surfaces in 3D space. The Geom package provides many implementations of concrete derived surfaces, such as planes, cylinders, cones, spheres and tori, surfaces of linear extrusion, surfaces of revolution, Bezier and BSpline surfaces, and so on. The key characteristic of these surfaces is that they are parameterized. Geom_Surface demonstrates:

    • how to work with the parametric equation of a surface to compute the point of parameters (u, v), and, at this point, the 1st, 2nd ... Nth derivative;
    • how to find global information about a surface in each parametric direction (for example, level of continuity, whether the surface is closed, its periodicity, the bounds of the parameters and so on);
    • how the parameters change when geometric transformations are applied to the surface, or the orientation is modified.

    Note that all surfaces must have a geometric continuity, and any surface is at least "C0". Generally, continuity is checked at construction time or when the curve is edited. Where this is not the case, the documentation makes this explicit.

    Warning The Geom package does not prevent the construction of surfaces with null areas, or surfaces which self-intersect.

    Member Function Documentation

    ◆ Bounds()

    virtual void Geom_Surface::Bounds ( double & U1,
    double & U2,
    double & V1,
    double & V2 ) const
    pure virtual

    ◆ Continuity()

    virtual GeomAbs_Shape Geom_Surface::Continuity ( ) const
    pure virtual

    Returns the Global Continuity of the surface in direction U and V :

    • C0: only geometric continuity,
    • C1: continuity of the first derivative all along the surface,
    • C2: continuity of the second derivative all along the surface,
    • C3: continuity of the third derivative all along the surface,
    • G1: tangency continuity all along the surface,
    • G2: curvature continuity all along the surface,
    • CN: the order of continuity is infinite.

    Example: If the surface is C1 in the V parametric direction and C2 in the U parametric direction Shape = C1.

    Implemented in Geom_BezierSurface, Geom_BSplineSurface, Geom_ElementarySurface, Geom_OffsetSurface, Geom_RectangularTrimmedSurface, Geom_SweptSurface, GeomEval_AHTBezierSurface, GeomEval_TBezierSurface, GeomPlate_Surface, and ShapeExtend_CompositeSurface.

    ◆ D0()

    void Geom_Surface::D0 ( const double U,
    const double V,
    gp_Pnt & P ) const
    inline

    Computes the point of parameter (U, V).

    ◆ D1()

    void Geom_Surface::D1 ( const double U,
    const double V,
    gp_Pnt & P,
    gp_Vec & D1U,
    gp_Vec & D1V ) const
    inline

    Computes the point and first partial derivatives.

    ◆ D2()

    void Geom_Surface::D2 ( const double U,
    const double V,
    gp_Pnt & P,
    gp_Vec & D1U,
    gp_Vec & D1V,
    gp_Vec & D2U,
    gp_Vec & D2V,
    gp_Vec & D2UV ) const
    inline

    Computes the point and partial derivatives up to 2nd order.

    ◆ D3()

    void Geom_Surface::D3 ( const double U,
    const double V,
    gp_Pnt & P,
    gp_Vec & D1U,
    gp_Vec & D1V,
    gp_Vec & D2U,
    gp_Vec & D2V,
    gp_Vec & D2UV,
    gp_Vec & D3U,
    gp_Vec & D3V,
    gp_Vec & D3UUV,
    gp_Vec & D3UVV ) const
    inline

    Computes the point and partial derivatives up to 3rd order.

    ◆ DN()

    gp_Vec Geom_Surface::DN ( const double U,
    const double V,
    const int Nu,
    const int Nv ) const
    inline

    Computes the derivative of order Nu in U and Nv in V.

    ◆ DumpJson()

    ◆ EvalD0()

    ◆ EvalD1()

    ◆ EvalD2()

    ◆ EvalD3()

    ◆ EvalDN()

    ◆ IsCNu()

    virtual bool Geom_Surface::IsCNu ( const int N) const
    pure virtual

    ◆ IsCNv()

    virtual bool Geom_Surface::IsCNv ( const int N) const
    pure virtual

    ◆ IsUClosed()

    virtual bool Geom_Surface::IsUClosed ( ) const
    pure virtual

    Checks whether this surface is closed in the u parametric direction. Returns true if, in the u parametric direction: taking uFirst and uLast as the parametric bounds in the u parametric direction, for each parameter v, the distance between the points P(uFirst, v) and P(uLast, v) is less than or equal to gp::Resolution().

    Implemented in Geom_BezierSurface, Geom_BSplineSurface, Geom_ConicalSurface, Geom_CylindricalSurface, Geom_OffsetSurface, Geom_Plane, Geom_RectangularTrimmedSurface, Geom_SphericalSurface, Geom_SurfaceOfLinearExtrusion, Geom_SurfaceOfRevolution, Geom_ToroidalSurface, GeomEval_AHTBezierSurface, GeomEval_CircularHelicoidSurface, GeomEval_EllipsoidSurface, GeomEval_HyperboloidSurface, GeomEval_HypParaboloidSurface, GeomEval_ParaboloidSurface, GeomEval_TBezierSurface, GeomPlate_Surface, and ShapeExtend_CompositeSurface.

    ◆ IsUPeriodic()

    virtual bool Geom_Surface::IsUPeriodic ( ) const
    pure virtual

    Checks if this surface is periodic in the u parametric direction. Returns true if:

    • this surface is closed in the u parametric direction, and
    • there is a constant T such that the distance between the points P (u, v) and P (u + T, v) (or the points P (u, v) and P (u, v + T)) is less than or equal to gp::Resolution().

    Note: T is the parametric period in the u parametric direction.

    Implemented in Geom_BezierSurface, Geom_BSplineSurface, Geom_ConicalSurface, Geom_CylindricalSurface, Geom_OffsetSurface, Geom_Plane, Geom_RectangularTrimmedSurface, Geom_SphericalSurface, Geom_SurfaceOfLinearExtrusion, Geom_SurfaceOfRevolution, Geom_ToroidalSurface, GeomEval_AHTBezierSurface, GeomEval_CircularHelicoidSurface, GeomEval_EllipsoidSurface, GeomEval_HyperboloidSurface, GeomEval_HypParaboloidSurface, GeomEval_ParaboloidSurface, GeomEval_TBezierSurface, GeomPlate_Surface, and ShapeExtend_CompositeSurface.

    ◆ IsVClosed()

    virtual bool Geom_Surface::IsVClosed ( ) const
    pure virtual

    Checks whether this surface is closed in the u parametric direction. Returns true if, in the v parametric direction: taking vFirst and vLast as the parametric bounds in the v parametric direction, for each parameter u, the distance between the points P(u, vFirst) and P(u, vLast) is less than or equal to gp::Resolution().

    Implemented in Geom_BezierSurface, Geom_BSplineSurface, Geom_ConicalSurface, Geom_CylindricalSurface, Geom_OffsetSurface, Geom_Plane, Geom_RectangularTrimmedSurface, Geom_SphericalSurface, Geom_SurfaceOfLinearExtrusion, Geom_SurfaceOfRevolution, Geom_ToroidalSurface, GeomEval_AHTBezierSurface, GeomEval_CircularHelicoidSurface, GeomEval_EllipsoidSurface, GeomEval_HyperboloidSurface, GeomEval_HypParaboloidSurface, GeomEval_ParaboloidSurface, GeomEval_TBezierSurface, GeomPlate_Surface, and ShapeExtend_CompositeSurface.

    ◆ IsVPeriodic()

    virtual bool Geom_Surface::IsVPeriodic ( ) const
    pure virtual

    Checks if this surface is periodic in the v parametric direction. Returns true if:

    • this surface is closed in the v parametric direction, and
    • there is a constant T such that the distance between the points P (u, v) and P (u + T, v) (or the points P (u, v) and P (u, v + T)) is less than or equal to gp::Resolution().

    Note: T is the parametric period in the v parametric direction.

    Implemented in Geom_BezierSurface, Geom_BSplineSurface, Geom_ConicalSurface, Geom_CylindricalSurface, Geom_OffsetSurface, Geom_Plane, Geom_RectangularTrimmedSurface, Geom_SphericalSurface, Geom_SurfaceOfLinearExtrusion, Geom_SurfaceOfRevolution, Geom_ToroidalSurface, GeomEval_AHTBezierSurface, GeomEval_CircularHelicoidSurface, GeomEval_EllipsoidSurface, GeomEval_HyperboloidSurface, GeomEval_HypParaboloidSurface, GeomEval_ParaboloidSurface, GeomEval_TBezierSurface, GeomPlate_Surface, and ShapeExtend_CompositeSurface.

    ◆ ParametricTransformation()

    virtual gp_GTrsf2d Geom_Surface::ParametricTransformation ( const gp_Trsf & T) const
    virtual

    Returns a 2d transformation used to find the new parameters of a point on the transformed surface.

    me->Transformed(T)->Value(U',V')

    is the same point as

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

    Where U',V' are obtained by transforming U,V with the 2d transformation returned by

    me->ParametricTransformation(T)

    This method returns an identity transformation

    It can be redefined. For example on the Plane, Cylinder, Cone, Revolved and Extruded surfaces.

    Reimplemented in Geom_ConicalSurface, Geom_CylindricalSurface, Geom_OffsetSurface, Geom_Plane, Geom_RectangularTrimmedSurface, Geom_SurfaceOfLinearExtrusion, Geom_SurfaceOfRevolution, and GeomPlate_Surface.

    ◆ TransformParameters()

    virtual void Geom_Surface::TransformParameters ( double & U,
    double & V,
    const gp_Trsf & T ) const
    virtual

    Computes the parameters on the transformed surface for the transform of the point of parameters U,V on <me>.

    me->Transformed(T)->Value(U',V')

    is the same point as

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

    Where U',V' are the new values of U,V after calling

    me->TransformParameters(U,V,T)

    This method does not change and <V>

    It can be redefined. For example on the Plane, Cylinder, Cone, Revolved and Extruded surfaces.

    Reimplemented in Geom_ConicalSurface, Geom_CylindricalSurface, Geom_OffsetSurface, Geom_Plane, Geom_RectangularTrimmedSurface, Geom_SurfaceOfLinearExtrusion, Geom_SurfaceOfRevolution, and GeomPlate_Surface.

    ◆ UIso()

    ◆ UPeriod()

    virtual double Geom_Surface::UPeriod ( ) const
    virtual

    Returns the period of this surface in the u parametric direction. Raises if the surface is not uperiodic.

    Reimplemented in Geom_OffsetSurface, Geom_RectangularTrimmedSurface, and GeomPlate_Surface.

    ◆ UReverse()

    ◆ UReversed()

    occ::handle< Geom_Surface > Geom_Surface::UReversed ( ) const
    nodiscard

    Reverses the U direction of parametrization of <me>. The bounds of the surface are not modified. A copy of <me> is returned.

    ◆ UReversedParameter()

    ◆ Value()

    gp_Pnt Geom_Surface::Value ( const double U,
    const double V ) const
    inline

    Computes the point of parameter (U, V) on the surface.

    ◆ VIso()

    ◆ VPeriod()

    virtual double Geom_Surface::VPeriod ( ) const
    virtual

    Returns the period of this surface in the v parametric direction. raises if the surface is not vperiodic.

    Reimplemented in Geom_OffsetSurface, Geom_RectangularTrimmedSurface, and GeomPlate_Surface.

    ◆ VReverse()

    ◆ VReversed()

    occ::handle< Geom_Surface > Geom_Surface::VReversed ( ) const
    nodiscard

    Reverses the V direction of parametrization of <me>. The bounds of the surface are not modified. A copy of <me> is returned.

    ◆ VReversedParameter()


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