GeomConvert_CompBezierSurfacesToBSplineSurface Class Reference

An algorithm to convert a grid of adjacent
non-rational Bezier surfaces into a BSpline surface.
A CompBezierSurfacesToBSplineSurface object
provides a framework for:
More...

#include <GeomConvert_CompBezierSurfacesToBSplineSurface.hxx>

Public Member Functions
	GeomConvert_CompBezierSurfacesToBSplineSurface (const TColGeom_Array2OfBezierSurface &Beziers)
	Computes all the data needed to build a "C0" <br> continuous BSpline surface equivalent to the grid of adjacent non-rational Bezier surfaces Beziers. Each surface in the Beziers grid becomes a natural patch, limited by knots values, on the BSpline surface whose data is computed. Surfaces in the grid must satisfy the following conditions: More...
	GeomConvert_CompBezierSurfacesToBSplineSurface (const TColGeom_Array2OfBezierSurface &Beziers, const Standard_Real Tolerance, const Standard_Boolean RemoveKnots=Standard_True)
	Build an Ci uniform (Rational) BSpline surface <br> The higest Continuity Ci is imposed, like the <br> maximal deformation is lower than <Tolerance>. <br> Warning: The Continuity C0 is imposed without any check. More...
	GeomConvert_CompBezierSurfacesToBSplineSurface (const TColGeom_Array2OfBezierSurface &Beziers, const TColStd_Array1OfReal &UKnots, const TColStd_Array1OfReal &VKnots, const GeomAbs_Shape UContinuity=GeomAbs_C0, const GeomAbs_Shape VContinuity=GeomAbs_C0, const Standard_Real Tolerance=1.0e-4)
	Computes all the data needed to construct a BSpline <br> surface equivalent to the adjacent non-rational Bezier surfaces Beziers grid. Each surface in the Beziers grid becomes a natural patch, limited by knots values, on the BSpline surface whose data is computed. Surfaces in the grid must satisfy the following conditions: More...
Standard_Integer	NbUKnots () const
	Returns the number of knots in the U direction <br> of the BSpline surface whose data is computed in this framework. More...
Standard_Integer	NbUPoles () const
	Returns number of poles in the U direction <br> of the BSpline surface whose data is computed in this framework. More...
Standard_Integer	NbVKnots () const
	Returns the number of knots in the V direction <br> of the BSpline surface whose data is computed in this framework. More...
Standard_Integer	NbVPoles () const
	Returns the number of poles in the V direction <br> of the BSpline surface whose data is computed in this framework. More...
const Handle_TColgp_HArray2OfPnt &	Poles () const
	Returns the table of poles of the BSpline surface <br> whose data is computed in this framework. More...
const Handle_TColStd_HArray1OfReal &	UKnots () const
	Returns the knots table for the u parametric <br> direction of the BSpline surface whose data is computed in this framework. More...
Standard_Integer	UDegree () const
	Returns the degree for the u parametric <br> direction of the BSpline surface whose data is computed in this framework. More...
const Handle_TColStd_HArray1OfReal &	VKnots () const
	Returns the knots table for the v parametric <br> direction of the BSpline surface whose data is computed in this framework. More...
Standard_Integer	VDegree () const
	Returns the degree for the v parametric <br> direction of the BSpline surface whose data is computed in this framework. More...
const Handle_TColStd_HArray1OfInteger &	UMultiplicities () const
	Returns the multiplicities table for the u parametric direction of the knots of the BSpline surface whose data is computed in this framework. More...
const Handle_TColStd_HArray1OfInteger &	VMultiplicities () const
	-- Returns the multiplicities table for the v <br> parametric direction of the knots of the BSpline surface whose data is computed in this framework. More...
Standard_Boolean	IsDone () const
	Returns true if the conversion was successful. <br> Unless an exception was raised at the time of construction, the conversion of the Bezier surface grid assigned to this algorithm is always carried out. IsDone returns false if the constraints defined at the time of construction cannot be respected. This occurs when there is an incompatibility between a required degree of continuity on the BSpline surface, and the maximum tolerance accepted for local deformations of the surface. In such a case the computed data does not satisfy all the initial constraints. More...

Detailed Description

An algorithm to convert a grid of adjacent
non-rational Bezier surfaces into a BSpline surface.
A CompBezierSurfacesToBSplineSurface object
provides a framework for:

• defining the grid of adjacent Bezier surfaces
  which is to be converted into a BSpline surface,
  
• implementing the computation algorithm, and
  
• consulting the results.
  Warning
  Do not attempt to convert rational Bezier surfaces using such an algorithm.
  Input is array of Bezier patch
  1 2 3 4 -> VIndex [1, NbVPatches] -> VDirection
  --------------------—
  1 | | | | |
  --------------------—
  2 | | | | |
  --------------------—
  3 | | | | |
  --------------------—
  UIndex [1, NbUPatches] Udirection
  
  Warning! Patches must have compatible parametrization
  

Constructor & Destructor Documentation

GeomConvert_CompBezierSurfacesToBSplineSurface::GeomConvert_CompBezierSurfacesToBSplineSurface

(

const TColGeom_Array2OfBezierSurface &

Beziers

)

  Computes all the data needed to build a "C0" <br>

continuous BSpline surface equivalent to the grid of
adjacent non-rational Bezier surfaces Beziers.
Each surface in the Beziers grid becomes a natural
patch, limited by knots values, on the BSpline surface
whose data is computed. Surfaces in the grid must
satisfy the following conditions:

• Coincident bounding curves between two
  consecutive surfaces in a row of the Beziers grid
  must be u-isoparametric bounding curves of these two surfaces.
  
• Coincident bounding curves between two
  consecutive surfaces in a column of the Beziers
  grid must be v-isoparametric bounding curves of these two surfaces.
  The BSpline surface whose data is computed has the
  following characteristics:
  
• Its degree in the u (respectively v) parametric
  direction is equal to that of the Bezier surface
  which has the highest degree in the u
  (respectively v) parametric direction in the Beziers grid.
  
• It is a "Piecewise Bezier" in both u and v
  parametric directions, i.e.:
  
  • the knots are regularly spaced in each
    parametric direction (i.e. the difference between
    two consecutive knots is a constant), and
    
  • all the multiplicities of the surface knots in a
    given parametric direction are equal to
    Degree, which is the degree of the BSpline
    surface in this parametric direction, except for
    the first and last knots for which the multiplicity is
    equal to Degree + 1.
    
• Coincident bounding curves between two
  consecutive columns of Bezier surfaces in the
  Beziers grid become u-isoparametric curves,
  corresponding to knots values of the BSpline surface.
  
• Coincident bounding curves between two
  consecutive rows of Bezier surfaces in the Beziers
  grid become v-isoparametric curves
  corresponding to knots values of the BSpline surface.
  Use the available consultation functions to access the
  computed data. This data may be used to construct the BSpline surface.
  Warning
  The surfaces in the Beziers grid must be adjacent, i.e.
  two consecutive Bezier surfaces in the grid (in a row
  or column) must have a coincident bounding curve. In
  addition, the location of the parameterization on each
  of these surfaces (i.e. the relative location of u and v
  isoparametric curves on the surface) is of importance
  with regard to the positioning of the surfaces in the
  Beziers grid. Care must be taken with respect to the
  above, as these properties are not checked and an
  error may occur if they are not satisfied.
  Exceptions
  Standard_NotImplemented if one of the Bezier
  surfaces of the Beziers grid is rational.
  

GeomConvert_CompBezierSurfacesToBSplineSurface::GeomConvert_CompBezierSurfacesToBSplineSurface	(	const TColGeom_Array2OfBezierSurface &	Beziers,
		const Standard_Real	Tolerance,
		const Standard_Boolean	RemoveKnots = Standard_True
	)

Build an Ci uniform (Rational) BSpline surface <br>
     The higest Continuity Ci is imposed, like the <br>
     maximal deformation is lower than <Tolerance>. <br>

Warning: The Continuity C0 is imposed without any check.

GeomConvert_CompBezierSurfacesToBSplineSurface::GeomConvert_CompBezierSurfacesToBSplineSurface	(	const TColGeom_Array2OfBezierSurface &	Beziers,
		const TColStd_Array1OfReal &	UKnots,
		const TColStd_Array1OfReal &	VKnots,
		const GeomAbs_Shape	UContinuity = GeomAbs_C0,
		const GeomAbs_Shape	VContinuity = GeomAbs_C0,
		const Standard_Real	Tolerance = 1.0e-4
	)

  Computes all the data needed to construct a BSpline <br>

surface equivalent to the adjacent non-rational
Bezier surfaces Beziers grid.
Each surface in the Beziers grid becomes a natural
patch, limited by knots values, on the BSpline surface
whose data is computed. Surfaces in the grid must
satisfy the following conditions:

• Coincident bounding curves between two
  consecutive surfaces in a row of the Beziers grid
  must be u-isoparametric bounding curves of these two surfaces.
  
• Coincident bounding curves between two
  consecutive surfaces in a column of the Beziers
  grid must be v-isoparametric bounding curves of these two surfaces.
  The BSpline surface whose data is computed has the
  following characteristics:
  
• Its degree in the u (respectively v) parametric
  direction is equal to that of the Bezier surface
  which has the highest degree in the u
  (respectively v) parametric direction in the Beziers grid.
  
• Coincident bounding curves between two
  consecutive columns of Bezier surfaces in the
  Beziers grid become u-isoparametric curves
  corresponding to knots values of the BSpline surface.
  
• Coincident bounding curves between two
  consecutive rows of Bezier surfaces in the Beziers
  grid become v-isoparametric curves
  corresponding to knots values of the BSpline surface.
  Knots values of the BSpline surface are given in the two tables:
  
• UKnots for the u parametric direction (which
  corresponds to the order of Bezier surface columns in the Beziers grid), and
  
• VKnots for the v parametric direction (which
  corresponds to the order of Bezier surface rows in the Beziers grid).
  The dimensions of UKnots (respectively VKnots)
  must be equal to the number of columns (respectively,
  rows) of the Beziers grid, plus 1 .
  UContinuity and VContinuity, which are both
  defaulted to GeomAbs_C0, specify the required
  continuity on the BSpline surface. If the required
  degree of continuity is greater than 0 in a given
  parametric direction, a deformation is applied locally
  on the initial surface (as defined by the Beziers grid)
  to satisfy this condition. This local deformation is not
  applied however, if it is greater than Tolerance
  (defaulted to 1.0 e-7). In such cases, the
  continuity condition is not satisfied, and the function
  IsDone will return false. A small tolerance value
  prevents any modification of the surface and a large
  tolerance value "smoothes" the surface.
  Use the available consultation functions to access the
  computed data. This data may be used to construct the BSpline surface.
  Warning
  The surfaces in the Beziers grid must be adjacent, i.e.
  two consecutive Bezier surfaces in the grid (in a row
  or column) must have a coincident bounding curve. In
  addition, the location of the parameterization on each
  of these surfaces (i.e. the relative location of u and v
  isoparametric curves on the surface) is of importance
  with regard to the positioning of the surfaces in the
  Beziers grid. Care must be taken with respect to the
  above, as these properties are not checked and an
  error may occur if they are not satisfied.
  Exceptions
  Standard_DimensionMismatch:
  
• if the number of knots in the UKnots table (i.e. the
  length of the UKnots array) is not equal to the
  number of columns of Bezier surfaces in the
  Beziers grid plus 1, or
  
• if the number of knots in the VKnots table (i.e. the
  length of the VKnots array) is not equal to the
  number of rows of Bezier surfaces in the Beziers grid, plus 1.
  Standard_ConstructionError:
  
• if UContinuity and VContinuity are not equal to
  one of the following values: GeomAbs_C0,
  GeomAbs_C1, GeomAbs_C2 and GeomAbs_C3; or
  
• if the number of columns in the Beziers grid is
  greater than 1, and the required degree of
  continuity in the u parametric direction is greater
  than that of the Bezier surface with the highest
  degree in the u parametric direction (in the Beziers grid), minus 1; or
  
• if the number of rows in the Beziers grid is
  greater than 1, and the required degree of
  continuity in the v parametric direction is greater
  than that of the Bezier surface with the highest
  degree in the v parametric direction (in the Beziers grid), minus 1 .
  Standard_NotImplemented if one of the Bezier
  surfaces in the Beziers grid is rational.
  

Member Function Documentation

Standard_Boolean GeomConvert_CompBezierSurfacesToBSplineSurface::IsDone

(

)

const

 Returns true if the conversion was successful. <br>

Unless an exception was raised at the time of
construction, the conversion of the Bezier surface
grid assigned to this algorithm is always carried out.
IsDone returns false if the constraints defined at the
time of construction cannot be respected. This occurs
when there is an incompatibility between a required
degree of continuity on the BSpline surface, and the
maximum tolerance accepted for local deformations
of the surface. In such a case the computed data
does not satisfy all the initial constraints.

Standard_Integer GeomConvert_CompBezierSurfacesToBSplineSurface::NbUKnots

(

)

const

  Returns the number of knots in the U direction <br>

of the BSpline surface whose data is computed in this framework.

Standard_Integer GeomConvert_CompBezierSurfacesToBSplineSurface::NbUPoles

(

)

const

 Returns number of poles in the U direction <br>

of the BSpline surface whose data is computed in this framework.

Standard_Integer GeomConvert_CompBezierSurfacesToBSplineSurface::NbVKnots

(

)

const

 Returns the number of knots in the V direction <br>

of the BSpline surface whose data is computed in this framework.

Standard_Integer GeomConvert_CompBezierSurfacesToBSplineSurface::NbVPoles

(

)

const

 Returns the number of poles in the V direction <br>

of the BSpline surface whose data is computed in this framework.

const Handle_TColgp_HArray2OfPnt& GeomConvert_CompBezierSurfacesToBSplineSurface::Poles

(

)

const

  Returns the table of poles of the BSpline surface <br>

whose data is computed in this framework.

Standard_Integer GeomConvert_CompBezierSurfacesToBSplineSurface::UDegree

(

)

const

 Returns the degree for the u  parametric <br>

direction of the BSpline surface whose data is computed in this framework.

const Handle_TColStd_HArray1OfReal& GeomConvert_CompBezierSurfacesToBSplineSurface::UKnots

(

)

const

 Returns the knots table for the u parametric <br>

direction of the BSpline surface whose data is computed in this framework.

const Handle_TColStd_HArray1OfInteger& GeomConvert_CompBezierSurfacesToBSplineSurface::UMultiplicities

(

)

const

Returns the multiplicities table for the u
parametric direction of the knots of the BSpline
surface whose data is computed in this framework.

Standard_Integer GeomConvert_CompBezierSurfacesToBSplineSurface::VDegree

(

)

const

 Returns the degree for the v  parametric <br>

direction of the BSpline surface whose data is computed in this framework.

const Handle_TColStd_HArray1OfReal& GeomConvert_CompBezierSurfacesToBSplineSurface::VKnots

(

)

const

 Returns the knots table for the v parametric <br>

direction of the BSpline surface whose data is computed in this framework.

const Handle_TColStd_HArray1OfInteger& GeomConvert_CompBezierSurfacesToBSplineSurface::VMultiplicities

(

)

const

 -- Returns the multiplicities table for the v <br>

parametric direction of the knots of the BSpline
surface whose data is computed in this framework.

---

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

• GeomConvert_CompBezierSurfacesToBSplineSurface.hxx