Open CASCADE Technology 6.6.0
Public Member Functions
GeomConvert_BSplineSurfaceToBezierSurface Class Reference

This algorithm converts a B-spline surface into several
Bezier surfaces. It uses an algorithm of knot insertion.
A BSplineSurfaceToBezierSurface object provides a framework for:
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#include <GeomConvert_BSplineSurfaceToBezierSurface.hxx>

Public Member Functions

 GeomConvert_BSplineSurfaceToBezierSurface (const Handle< Geom_BSplineSurface > &BasisSurface)
 Computes all the data needed to convert

 GeomConvert_BSplineSurfaceToBezierSurface (const Handle< Geom_BSplineSurface > &BasisSurface, const Standard_Real U1, const Standard_Real U2, const Standard_Real V1, const Standard_Real V2, const Standard_Real ParametricTolerance)
 Computes all the data needed to convert
the patch of the BSpline surface BasisSurface
limited by the two parameter values U1 and U2 in
the u parametric direction, and by the two
parameter values V1 and V2 in the v parametric
direction, into a series of adjacent Bezier surfaces.
The result consists of a grid of BasisSurface patches
limited by isoparametric curves corresponding to knot
values, both in the u and v parametric directions of
the surface. A row in the grid corresponds to a series
of adjacent patches, all limited by the same two
u-isoparametric curves. A column in the grid
corresponds to a series of adjacent patches, all
limited by the same two v-isoparametric curves.
Use the available interrogation functions to ascertain
the number of computed Bezier patches, and then to
construct each individual Bezier surface (or all Bezier surfaces).
Note: ParametricTolerance is not used. Raises DomainError
if U1 or U2 or V1 or V2 are out of the parametric bounds
of the basis surface [FirstUKnotIndex, LastUKnotIndex] ,
[FirstVKnotIndex, LastVKnotIndex] The tolerance criterion is
ParametricTolerance.
Raised if U2 - U1 <= ParametricTolerance or
V2 - V1 <= ParametricTolerance.

Handle_Geom_BezierSurface Patch (const Standard_Integer UIndex, const Standard_Integer VIndex)
 Constructs and returns the Bezier surface of indices
(UIndex, VIndex) to the patch grid computed on the
BSpline surface analyzed by this algorithm.
This Bezier surface has the same orientation as the
BSpline surface analyzed in this framework.
UIndex is an index common to a row in the patch
grid. A row in the grid corresponds to a series of
adjacent patches, all limited by the same two
u-isoparametric curves of the surface. VIndex is an
index common to a column in the patch grid. A column
in the grid corresponds to a series of adjacent
patches, all limited by the same two v-isoparametric
curves of the surface.
Exceptions
Standard_OutOfRange if:

void Patches (TColGeom_Array2OfBezierSurface &Surfaces)
 Constructs all the Bezier surfaces whose data is
computed by this algorithm, and loads them into the Surfaces table.
These Bezier surfaces have the same orientation as
the BSpline surface analyzed in this framework.
The Surfaces array is organised in the same way as
the patch grid computed on the BSpline surface
analyzed by this algorithm. A row in the array
corresponds to a series of adjacent patches, all
limited by the same two u-isoparametric curves of
the surface. A column in the array corresponds to a
series of adjacent patches, all limited by the same two
v-isoparametric curves of the surface.
Exceptions
Standard_DimensionError if the Surfaces array
was not created with the following bounds:

void UKnots (TColStd_Array1OfReal &TKnots) const
 This methode returns the bspline's u-knots associated to
the converted Patches
//! Raised if the length of Curves is not equal to
NbUPatches + 1.

void VKnots (TColStd_Array1OfReal &TKnots) const
 This methode returns the bspline's v-knots associated to
the converted Patches
//! Raised if the length of Curves is not equal to
NbVPatches + 1.

Standard_Integer NbUPatches () const
 Returns the number of Bezier surfaces in the U direction.
If at the creation time you have decomposed the basis Surface
between the parametric values UFirst, ULast the number of
Bezier surfaces in the U direction depends on the number of
knots included inside the interval [UFirst, ULast].
If you have decomposed the whole basis B-spline surface the
number of Bezier surfaces NbUPatches is equal to the number of
UKnots less one.

Standard_Integer NbVPatches () const
 Returns the number of Bezier surfaces in the V direction.
If at the creation time you have decomposed the basis surface
between the parametric values VFirst, VLast the number of
Bezier surfaces in the V direction depends on the number of
knots included inside the interval [VFirst, VLast].
If you have decomposed the whole basis B-spline surface the
number of Bezier surfaces NbVPatches is equal to the number of
VKnots less one.


Detailed Description


Constructor & Destructor Documentation

GeomConvert_BSplineSurfaceToBezierSurface::GeomConvert_BSplineSurfaceToBezierSurface ( const Handle< Geom_BSplineSurface > &  BasisSurface)
  • the BSpline surface BasisSurface into a series of adjacent Bezier surfaces.
    The result consists of a grid of BasisSurface patches
    limited by isoparametric curves corresponding to knot
    values, both in the u and v parametric directions of
    the surface. A row in the grid corresponds to a series
    of adjacent patches, all limited by the same two
    u-isoparametric curves. A column in the grid
    corresponds to a series of adjacent patches, all
    limited by the same two v-isoparametric curves.
    Use the available interrogation functions to ascertain
    the number of computed Bezier patches, and then to
    construct each individual Bezier surface (or all Bezier surfaces).
    Note: ParametricTolerance is not used.
GeomConvert_BSplineSurfaceToBezierSurface::GeomConvert_BSplineSurfaceToBezierSurface ( const Handle< Geom_BSplineSurface > &  BasisSurface,
const Standard_Real  U1,
const Standard_Real  U2,
const Standard_Real  V1,
const Standard_Real  V2,
const Standard_Real  ParametricTolerance 
)

Member Function Documentation

Standard_Integer GeomConvert_BSplineSurfaceToBezierSurface::NbUPatches ( ) const
Standard_Integer GeomConvert_BSplineSurfaceToBezierSurface::NbVPatches ( ) const
Handle_Geom_BezierSurface GeomConvert_BSplineSurfaceToBezierSurface::Patch ( const Standard_Integer  UIndex,
const Standard_Integer  VIndex 
)
  • UIndex is less than 1 or greater than the number
    of rows in the patch grid computed on the BSpline
    surface analyzed by this algorithm (as returned by
    the function NbUPatches); or if
  • VIndex is less than 1 or greater than the number
    of columns in the patch grid computed on the
    BSpline surface analyzed by this algorithm (as
    returned by the function NbVPatches).
void GeomConvert_BSplineSurfaceToBezierSurface::Patches ( TColGeom_Array2OfBezierSurface Surfaces)
  • 1, and the number of adjacent patch series in the
    u parametric direction of the patch grid computed
    on the BSpline surface, analyzed by this algorithm
    (as given by the function NbUPatches) as row bounds,
  • 1, and the number of adjacent patch series in the
    v parametric direction of the patch grid computed
    on the BSpline surface, analyzed by this algorithm
    (as given by the function NbVPatches) as column bounds.
void GeomConvert_BSplineSurfaceToBezierSurface::UKnots ( TColStd_Array1OfReal TKnots) const
void GeomConvert_BSplineSurfaceToBezierSurface::VKnots ( TColStd_Array1OfReal TKnots) const

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