OCC.Core.Geom2dConvert module

Geom2dConvert module, see official documentation at https://www.opencascade.com/doc/occt-7.4.0/refman/html/package_geom2dconvert.html

class Geom2dConvert_ApproxCurve(*args)

Bases: object

• Constructs an approximation framework defined by - the 2D conic Curve - the tolerance value Tol2d - the degree of continuity Order - the maximum number of segments allowed MaxSegments - the highest degree MaxDegree which the polynomial defining the BSpline is allowed to have.

  param Curve

  type Curve

  Geom2d_Curve

  param Tol2d

  type Tol2d

  float

  param Order

  type Order

  GeomAbs_Shape

  param MaxSegments

  type MaxSegments

  int

  param MaxDegree

  type MaxDegree

  int

  rtype

  None* Constructs an approximation framework defined by - the 2D conic Curve - the tolerance value Tol2d - the degree of continuity Order - the maximum number of segments allowed MaxSegments - the highest degree MaxDegree which the polynomial defining the BSpline is allowed to have.

  param Curve

  type Curve

  Adaptor2d_HCurve2d

  param Tol2d

  type Tol2d

  float

  param Order

  type Order

  GeomAbs_Shape

  param MaxSegments

  type MaxSegments

  int

  param MaxDegree

  type MaxDegree

  int

  rtype

  None

Curve()

• Returns the 2D BSpline curve resulting from the approximation algorithm.

  rtype

  opencascade::handle<Geom2d_BSplineCurve>

DumpToString(Geom2dConvert_ApproxCurve self) → std::string

HasResult()

• returns Standard_True if the approximation did come out with a result that is not NECESSARELY within the required tolerance

  rtype

  bool

IsDone()

• returns Standard_True if the approximation has been done with within requiered tolerance

  rtype

  bool

MaxError()

• Returns the greatest distance between a point on the source conic and the BSpline curve resulting from the approximation. (>0 when an approximation has been done, 0 if no approximation)

  rtype

  float

property thisown

The membership flag

class Geom2dConvert_BSplineCurveKnotSplitting(*args)

Bases: object

• Determines points at which the BSpline curve BasisCurve should be split in order to obtain arcs with a degree of continuity equal to ContinuityRange. These points are knot values of BasisCurve. They are identified by indices in the knots table of BasisCurve. Use the available interrogation functions to access computed values, followed by the global function SplitBSplineCurve (provided by the package Geom2dConvert) to split the curve. Exceptions Standard_RangeError if ContinuityRange is less than zero.

  param BasisCurve

  type BasisCurve

  Geom2d_BSplineCurve

  param ContinuityRange

  type ContinuityRange

  int

  rtype

  None

NbSplits()

• Returns the number of points at which the analysed BSpline curve should be split, in order to obtain arcs with the continuity required by this framework. All these points correspond to knot values. Note that the first and last points of the curve, which bound the first and last arcs, are counted among these splitting points.

  rtype

  int

SplitValue()

• Returns the split knot of index Index to the split knots table computed in this framework. The returned value is an index in the knots table of the BSpline curve analysed by this algorithm. Notes: - If Index is equal to 1, the corresponding knot gives the first point of the curve. - If Index is equal to the number of split knots computed in this framework, the corresponding point is the last point of the curve. Exceptions Standard_RangeError if Index is less than 1 or greater than the number of split knots computed in this framework.

  param Index

  type Index

  int

  rtype

  int

Splitting()

• Loads the SplitValues table with the split knots values computed in this framework. Each value in the table is an index in the knots table of the BSpline curve analysed by this algorithm. The values in SplitValues are given in ascending order and comprise the indices of the knots which give the first and last points of the curve. Use two consecutive values from the table as arguments of the global function SplitBSplineCurve (provided by the package Geom2dConvert) to split the curve. Exceptions Standard_DimensionError if the array SplitValues was not created with the following bounds: - 1, and - the number of split points computed in this framework (as given by the function NbSplits).

  param SplitValues

  type SplitValues

  TColStd_Array1OfInteger

  rtype

  None

property thisown

The membership flag

class Geom2dConvert_BSplineCurveToBezierCurve(*args)

Bases: object

• Computes all the data needed to convert - the BSpline curve BasisCurve, into a series of adjacent Bezier arcs. The result consists of a series of BasisCurve arcs limited by points corresponding to knot values of the curve. Use the available interrogation functions to ascertain the number of computed Bezier arcs, and then to construct each individual Bezier curve (or all Bezier curves). Note: ParametricTolerance is not used.

  param BasisCurve

  type BasisCurve

  Geom2d_BSplineCurve

  rtype

  None* Computes all the data needed to convert the portion of the BSpline curve BasisCurve limited by the two parameter values U1 and U2 for Example if there is a Knot Uk and Uk < U < Uk + ParametricTolerance/2 the last curve corresponds to the span [Uk-1, Uk] and not to [Uk, Uk+1] The result consists of a series of BasisCurve arcs limited by points corresponding to knot values of the curve. Use the available interrogation functions to ascertain the number of computed Bezier arcs, and then to construct each individual Bezier curve (or all Bezier curves). Note: ParametricTolerance is not used. Raises DomainError if U1 or U2 are out of the parametric bounds of the basis curve [FirstParameter, LastParameter]. The Tolerance criterion is ParametricTolerance. Raised if Abs (U2 - U1) <= ParametricTolerance.

  param BasisCurve

  type BasisCurve

  Geom2d_BSplineCurve

  param U1

  type U1

  float

  param U2

  type U2

  float

  param ParametricTolerance

  type ParametricTolerance

  float

  rtype

  None

Arc()

• Constructs and returns the Bezier curve of index Index to the table of adjacent Bezier arcs computed by this algorithm. This Bezier curve has the same orientation as the BSpline curve analyzed in this framework. Exceptions Standard_OutOfRange if Index is less than 1 or greater than the number of adjacent Bezier arcs computed by this algorithm.

  param Index

  type Index

  int

  rtype

  opencascade::handle<Geom2d_BezierCurve>

Arcs()

• Constructs all the Bezier curves whose data is computed by this algorithm and loads these curves into the Curves table. The Bezier curves have the same orientation as the BSpline curve analyzed in this framework. Exceptions Standard_DimensionError if the Curves array was not created with the following bounds: - 1 , and - the number of adjacent Bezier arcs computed by this algorithm (as given by the function NbArcs).

  param Curves

  type Curves

  TColGeom2d_Array1OfBezierCurve

  rtype

  None

Knots()

• This methode returns the bspline’s knots associated to the converted arcs Raises DimensionError if the length of Curves is not equal to NbArcs + 1

  param TKnots

  type TKnots

  TColStd_Array1OfReal

  rtype

  None

NbArcs()

• Returns the number of BezierCurve arcs. If at the creation time you have decomposed the basis curve between the parametric values UFirst, ULast the number of BezierCurve arcs depends on the number of knots included inside the interval [UFirst, ULast]. If you have decomposed the whole basis B-spline curve the number of BezierCurve arcs NbArcs is equal to the number of knots less one.

  rtype

  int

property thisown

The membership flag

class Geom2dConvert_CompCurveToBSplineCurve(*args)

Bases: object

• Initialize the algorithme - Parameterisation is used to convert

  param Parameterisation

  default value is Convert_TgtThetaOver2

  type Parameterisation

  Convert_ParameterisationType

  rtype

  None* Initialize the algorithme with one curve - Parameterisation is used to convert

  param BasisCurve

  type BasisCurve

  Geom2d_BoundedCurve

  param Parameterisation

  default value is Convert_TgtThetaOver2

  type Parameterisation

  Convert_ParameterisationType

  rtype

  None

Add()

• Append a curve in the BSpline Return False if the curve is not G0 with the BSplineCurve. Tolerance is used to check continuity and decrease Multiplicty at the common Knot After is usefull if BasisCurve is a closed curve .

  param NewCurve

  type NewCurve

  Geom2d_BoundedCurve

  param Tolerance

  type Tolerance

  float

  param After

  default value is Standard_False

  type After

  bool

  rtype

  bool

BSplineCurve()

Return type

opencascade::handle<Geom2d_BSplineCurve>

Clear()

• Clear result curve

  rtype

  None

property thisown

The membership flag

class SwigPyIterator(*args, **kwargs)

Bases: object

advance()

copy()

decr()

distance()

equal()

incr()

next()

previous()

property thisown

The membership flag

value()

class geom2dconvert

Bases: object

static C0BSplineToArrayOfC1BSplineCurve()

• This Method reduces as far as it is possible the multiplicities of the knots of the BSpline BS.(keeping the geometry). It returns an array of BSpline C1. Tolerance is a geometrical tolerance

  param BS

  type BS

  Geom2d_BSplineCurve

  param tabBS

  type tabBS

  TColGeom2d_HArray1OfBSplineCurve

  param Tolerance

  type Tolerance

  float

  rtype

  void* This Method reduces as far as it is possible the multiplicities of the knots of the BSpline BS.(keeping the geometry). It returns an array of BSpline C1. tolerance is a geometrical tolerance

  param BS

  type BS

  Geom2d_BSplineCurve

  param tabBS

  type tabBS

  TColGeom2d_HArray1OfBSplineCurve

  param AngularTolerance

  type AngularTolerance

  float

  param Tolerance

  type Tolerance

  float

  rtype

  void

static C0BSplineToC1BSplineCurve()

• This Method reduces as far as it is possible the multiplicities of the knots of the BSpline BS.(keeping the geometry). It returns a new BSpline which could still be C0. tolerance is a geometrical tolerance

  param BS

  type BS

  Geom2d_BSplineCurve

  param Tolerance

  type Tolerance

  float

  rtype

  void

static ConcatC1()

• This Method concatenates C1 the ArrayOfCurves as far as it is possible. ArrayOfCurves[0..N-1] ArrayOfToler contains the biggest tolerance of the two points shared by two consecutives curves. Its dimension: [0..N-2] ClosedFlag indicates if the ArrayOfCurves is closed. In this case ClosedTolerance contains the biggest tolerance of the two points which are at the closure. Otherwise its value is 0.0 ClosedFlag becomes False on the output if it is impossible to build closed curve.

  param ArrayOfCurves

  type ArrayOfCurves

  TColGeom2d_Array1OfBSplineCurve

  param ArrayOfToler

  type ArrayOfToler

  TColStd_Array1OfReal

  param ArrayOfIndices

  type ArrayOfIndices

  TColStd_HArray1OfInteger

  param ArrayOfConcatenated

  type ArrayOfConcatenated

  TColGeom2d_HArray1OfBSplineCurve

  param ClosedFlag

  type ClosedFlag

  bool

  param ClosedTolerance

  type ClosedTolerance

  float

  rtype

  void* This Method concatenates C1 the ArrayOfCurves as far as it is possible. ArrayOfCurves[0..N-1] ArrayOfToler contains the biggest tolerance of the two points shared by two consecutives curves. Its dimension: [0..N-2] ClosedFlag indicates if the ArrayOfCurves is closed. In this case ClosedTolerance contains the biggest tolerance of the two points which are at the closure. Otherwise its value is 0.0 ClosedFlag becomes False on the output if it is impossible to build closed curve.

  param ArrayOfCurves

  type ArrayOfCurves

  TColGeom2d_Array1OfBSplineCurve

  param ArrayOfToler

  type ArrayOfToler

  TColStd_Array1OfReal

  param ArrayOfIndices

  type ArrayOfIndices

  TColStd_HArray1OfInteger

  param ArrayOfConcatenated

  type ArrayOfConcatenated

  TColGeom2d_HArray1OfBSplineCurve

  param ClosedFlag

  type ClosedFlag

  bool

  param ClosedTolerance

  type ClosedTolerance

  float

  param AngularTolerance

  type AngularTolerance

  float

  rtype

  void

static ConcatG1()

• This Method concatenates G1 the ArrayOfCurves as far as it is possible. ArrayOfCurves[0..N-1] ArrayOfToler contains the biggest tolerance of the two points shared by two consecutives curves. Its dimension: [0..N-2] ClosedFlag indicates if the ArrayOfCurves is closed. In this case ClosedTolerance contains the biggest tolerance of the two points which are at the closure. Otherwise its value is 0.0 ClosedFlag becomes False on the output if it is impossible to build closed curve.

  param ArrayOfCurves

  type ArrayOfCurves

  TColGeom2d_Array1OfBSplineCurve

  param ArrayOfToler

  type ArrayOfToler

  TColStd_Array1OfReal

  param ArrayOfConcatenated

  type ArrayOfConcatenated

  TColGeom2d_HArray1OfBSplineCurve

  param ClosedFlag

  type ClosedFlag

  bool

  param ClosedTolerance

  type ClosedTolerance

  float

  rtype

  void

static CurveToBSplineCurve()

• This function converts a non infinite curve from Geom into a B-spline curve. C must be an ellipse or a circle or a trimmed conic or a trimmed line or a Bezier curve or a trimmed Bezier curve or a BSpline curve or a trimmed BSpline curve or an Offset curve or a trimmed Offset curve. The returned B-spline is not periodic except if C is a Circle or an Ellipse. ParameterisationType applies only if the curve is a Circle or an ellipseTgtThetaOver2, TgtThetaOver2_1, TgtThetaOver2_2, TgtThetaOver2_3, TgtThetaOver2_4, Purpose: this is the classical rational parameterisation 2 1 - t cos(theta) = —— 2 1 + t //! 2t sin(theta) = —— 2 1 + t //! t = tan (theta/2) //! with TgtThetaOver2 the routine will compute the number of spans using the rule num_spans = [ (ULast - UFirst) / 1.2 ] + 1 with TgtThetaOver2_N, N spans will be forced: an error will be raized if (ULast - UFirst) >= PI and N = 1, ULast - UFirst >= 2 PI and N = 2 //! QuasiAngular, here t is a rational function that approximates theta —-> tan(theta/2). Neverthless the composing with above function yields exact functions whose square sum up to 1 RationalC1 ; t is replaced by a polynomial function of u so as to grant C1 contiuity across knots. Exceptions Standard_DomainError if the curve C is infinite. Standard_ConstructionError: - if C is a complete circle or ellipse, and if Parameterisation is not equal to Convert_TgtThetaOver2 or to Convert_RationalC1, or - if C is a trimmed circle or ellipse and if Parameterisation is equal to Convert_TgtThetaOver2_1 and if U2 - U1 > 0.9999 * Pi where U1 and U2 are respectively the first and the last parameters of the trimmed curve (this method of parameterization cannot be used to convert a half-circle or a half-ellipse, for example), or - if C is a trimmed circle or ellipse and Parameterisation is equal to Convert_TgtThetaOver2_2 and U2 - U1 > 1.9999 * Pi where U1 and U2 are respectively the first and the last parameters of the trimmed curve (this method of parameterization cannot be used to convert a quasi-complete circle or ellipse).

  param C

  type C

  Geom2d_Curve

  param Parameterisation

  default value is Convert_TgtThetaOver2

  type Parameterisation

  Convert_ParameterisationType

  rtype

  opencascade::handle<Geom2d_BSplineCurve>

static SplitBSplineCurve()

• – Convert a curve to BSpline by Approximation //! This method computes the arc of B-spline curve between the two knots FromK1 and ToK2. If C is periodic the arc has the same orientation as C if SameOrientation = Standard_True. If C is not periodic SameOrientation is not used for the computation and C is oriented from the knot fromK1 to the knot toK2. We just keep the local definition of C between the knots FromK1 and ToK2. The returned B-spline curve has its first and last knots with a multiplicity equal to degree + 1, where degree is the polynomial degree of C. The indexes of the knots FromK1 and ToK2 doesn’t include the repetition of multiple knots in their definition. //! Raised if FromK1 or ToK2 are out of the bounds [FirstUKnotIndex, LastUKnotIndex] Raised if FromK1 = ToK2

  param C

  type C

  Geom2d_BSplineCurve

  param FromK1

  type FromK1

  int

  param ToK2

  type ToK2

  int

  param SameOrientation

  default value is Standard_True

  type SameOrientation

  bool

  rtype

  opencascade::handle<Geom2d_BSplineCurve>* This function computes the segment of B-spline curve between the parametric values FromU1, ToU2. If C is periodic the arc has the same orientation as C if SameOrientation = True. If C is not periodic SameOrientation is not used for the computation and C is oriented fromU1 toU2. If U1 and U2 and two parametric values we consider that U1 = U2 if Abs (U1 - U2) <= ParametricTolerance and ParametricTolerance must be greater or equal to Resolution from package gp. //! Raised if FromU1 or ToU2 are out of the parametric bounds of the curve (The tolerance criterion is ParametricTolerance). Raised if Abs (FromU1 - ToU2) <= ParametricTolerance Raised if ParametricTolerance < Resolution from gp.

  param C

  type C

  Geom2d_BSplineCurve

  param FromU1

  type FromU1

  float

  param ToU2

  type ToU2

  float

  param ParametricTolerance

  type ParametricTolerance

  float

  param SameOrientation

  default value is Standard_True

  type SameOrientation

  bool

  rtype

  opencascade::handle<Geom2d_BSplineCurve>

property thisown

The membership flag