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IKO_GeomAPI_Interpolate
IKO_GeomAPI_Interpolate Interface
The interface is used to interpolate a BsplineCurve
passing through an array of points, with a C2
Continuity if tangency is not requested at the point.
If tangency is requested at the point the continuity will
be C1. If Perodicity is requested the curve will be closed
and the junction will be the first point given. The curve
will than be only C1
Describes functions for building a constrained 3D BSpline curve.
The curve is defined by a table of points
through which it passes, and if required:
ï¿½ by a parallel table of reals which gives the
value of the parameter of each point through
which the resulting BSpline curve passes, and
ï¿½ by vectors tangential to these points.
An Interpolate object provides a framework for:
ï¿½ defining the constraints of the BSpline curve,
ï¿½ implementing the interpolation algorithm, and
ï¿½ consulting the results.
 Init
 Init2
 Load
 Load2
 ClearTangents
 Perform
 Curve
HRESULT Init(IKO_TColgp_Array1OfPnt* Points, VARIANT_BOOL Periodic, double Tolerance)
Initializes an algorithm for constructing a
constrained BSpline curve passing through the points of the table Points.
Tangential vectors can then be assigned, using the function Load.
If PeriodicFlag is true, the constrained BSpline
curve will be periodic and closed. In this case,
the junction point is the first point of the table Points.
The tolerance value Tolerance is used to check that:
ï¿½ points are not too close to each other, or
tangential vectors (defined using the
function Load) are not too small.
The resulting BSpline curve will be "C2"
continuous, except where a tangency
constraint is defined on a point through which
the curve passes (by using the Load function).
In this case, it will be only "C1" continuous.
Once all the constraints are defined, use the
function Perform to compute the curve.
Warning
ï¿½ There must be at least 2 points in the table Points.
ï¿½ If PeriodicFlag is false, there must be as
many parameters in the array Parameters as
there are points in the array Points.
ï¿½ If PeriodicFlag is true, there must be one
more parameter in the table Parameters: this
is used to give the parameter on the
resulting BSpline curve of the junction point
of the curve (which is also the first point of the table Points).
Exceptions
ï¿½ Standard_ConstructionError if the
distance between two consecutive points in
the table Points is less than or equal to Tolerance.
ï¿½ Standard_OutOfRange if:
o there are less than two points in the table Points, or
o conditions relating to the respective
number of elements in the parallel tables
Points and Parameters are not respected.
HRESULT Init2(IKO_TColgp_Array1OfPnt* Points, IKO_TColStd_Array1OfReal* Parameters, VARIANT_BOOL Periodic, double Tolerance)
Initializes an algorithm for constructing a constrained BSpline curve passing
through the points of the table Points, where the parameters of each of its
points are given by the parallel table Parameters. Tangential vectors can then
be assigned, using the function Load. If PeriodicFlag is true, the constrained
BSpline curve will be periodic and closed. In this case, the junction point is
the first point of the table Points.
The tolerance value Tolerance is used to check that: points are not too close to
each other, or tangential vectors (defined using the function Load) are not too
small. The resulting BSpline curve will be "C2" continuous, except where a
tangency constraint is defined on a point through which the curve passes (by
using the Load function). In this case, it will be only "C1" continuous. Once
all the constraints are defined, use the function Perform to compute the curve.
Warning There must be at least 2 points in the table Points. If PeriodicFlag is
false, there must be as many parameters in the array Parameters as there are
points in the array Points. If PeriodicFlag is true, there must be one more
parameter in the table Parameters: this is used to give the parameter on the
resulting BSpline curve of the junction point of the curve (which is also the
first point of the table Points).
Exceptions: Standard_ConstructionError if the distance between two consecutive
points in the table Points is less than or equal to Tolerance.
Standard_OutOfRange if: there are less than two points in the table Points, or
conditions relating to the respective number of elements in the parallel tables
Points and Parameters are not respected
HRESULT Load( DIVect* InitialTangent, DIVect* FinalTangent, VARIANT_BOOL Scale)
 Assigns this constrained BSpline curve to be tangential to vectors
InitialTangent and FinalTangent at its first and last points respectively (i.e.
the first and last points of the table of points through which the curve passes,
as defined at the time of initialization).
HRESULT Load2(IKO_TColgp_Array1OfVec* Tangents, IKO_TColStd_Array1OfBoolean* TangentFlags, VARIANT_BOOL Scale)
Assigns this constrained BSpline curve to be tangential to vectors defined in the
table Tangents, which is parallel to the table of points through which the curve
passes, as defined at the time of initialization. Vectors in the table Tangents
are defined only if the flag given in the parallel table TangentFlags is true:
only these vectors are set as tangency constraints.
HRESULT ClearTangents()
Clears all tangency constraints on this constrained BSpline curve (as initialized
by the function Load).
HRESULT Perform()
Computes the constrained BSpline curve. Use the function IsDone to verify that
the computation is successful, and then the function Curve to obtain the result.
HRESULT Curve(IKO_Geom_BSplineCurve** curve)
Returns the computed BSpline curve. Raises StdFail_NotDone if the interpolation
fails.
