BRepAlgoAPI_Section Class Reference

Computes the intersection of two shapes or geometries.
Geometries can be surfaces of planes.
Geometries are converted to faces
When a geometry has been converted to
topology the created shape can be found using
the methods Shape1 and Shape2 inherited from the class BooleanOperation.
The result (Shape() method) is a compound containing
edges built on intersection curves.
By default, the section is performed immediatly in
class constructors, with default values :
More...

#include <BRepAlgoAPI_Section.hxx>

Inheritance diagram for BRepAlgoAPI_Section:

Public Member Functions
	BRepAlgoAPI_Section (const TopoDS_Shape &S1, const TopoDS_Shape &S2, const BOPAlgo_PaveFiller &aDSF, const Standard_Boolean PerformNow=Standard_True)
virtual	~BRepAlgoAPI_Section ()
	BRepAlgoAPI_Section (const TopoDS_Shape &Sh1, const TopoDS_Shape &Sh2, const Standard_Boolean PerformNow=Standard_True)
	see upper More...
	BRepAlgoAPI_Section (const TopoDS_Shape &Sh, const gp_Pln &Pl, const Standard_Boolean PerformNow=Standard_True)
	see upper More...
	BRepAlgoAPI_Section (const TopoDS_Shape &Sh, const Handle< Geom_Surface > &Sf, const Standard_Boolean PerformNow=Standard_True)
	see upper More...
	BRepAlgoAPI_Section (const Handle< Geom_Surface > &Sf, const TopoDS_Shape &Sh, const Standard_Boolean PerformNow=Standard_True)
	see upper More...
	BRepAlgoAPI_Section (const Handle< Geom_Surface > &Sf1, const Handle< Geom_Surface > &Sf2, const Standard_Boolean PerformNow=Standard_True)
	This and the above classes construct a framework for <br> computing the section lines of: More...
void	Init1 (const TopoDS_Shape &S1)
	initialize first part More...
void	Init1 (const gp_Pln &Pl)
	initialize first part More...
void	Init1 (const Handle< Geom_Surface > &Sf)
	initialize first part More...
void	Init2 (const TopoDS_Shape &S2)
	initialize second part More...
void	Init2 (const gp_Pln &Pl)
	initialize second part More...
void	Init2 (const Handle< Geom_Surface > &Sf)
	Reinitializes the first and the <br> second parts on which this algorithm is going to perform the intersection computation. This is done with either: the surface Sf, the plane Pl or the shape Sh. You use the function Build to construct the result. More...
void	Approximation (const Standard_Boolean B)
	Defines an option for computation <br> of further intersections. This computation will be performed by the function Build in this framework. By default, the underlying 3D geometry attached to each elementary edge of the result of a computed intersection is: More...
void	ComputePCurveOn1 (const Standard_Boolean B)
	Indicates if the Pcurve must be (or not) performed on first part. More...
void	ComputePCurveOn2 (const Standard_Boolean B)
	Define options for the computation of further <br> intersections, which will be performed by the function Build in this framework. By default, no parametric 2D curve (pcurve) is defined for the elementary edges of the result. If ComputePCurve1 equals true, further computations performed in this framework with the function Build will attach an additional pcurve in the parametric space of the first shape to the constructed edges. If ComputePCurve2 equals true, the additional pcurve will be attached to the constructed edges in the parametric space of the second shape. These two functions may be used together. More...
void	Build ()
	Performs the computation of <br> section lines between two parts defined at the time of construction of this framework or reinitialized with the Init1 and Init2 functions. The constructed shape will be returned by the function Shape. This is a compound object composed of edges. These intersection edges may be built: More...
Standard_Boolean	HasAncestorFaceOn1 (const TopoDS_Shape &E, TopoDS_Shape &F) const
	get the face of the first part giving section edge <E>. Returns True on the 3 following conditions : 1/ <E> is an edge returned by the Shape() method. 2/ First part of section performed is a shape. 3/ <E> is built on a intersection curve (i.e <E> is not the result of common edges) When False, F remains untouched. More...
Standard_Boolean	HasAncestorFaceOn2 (const TopoDS_Shape &E, TopoDS_Shape &F) const
	Identifies the ancestor faces of <br> the intersection edge E resulting from the last computation performed in this framework, that is, the faces of the two original shapes on which the edge E lies: More...
Public Member Functions inherited from BRepAlgoAPI_BooleanOperation
void	SetOperation (const BOPAlgo_Operation anOp)
	Sets the type of Boolean operation to perform <br> It can be BOPAlgo_SECTION <br> BOPAlgo_COMMON <br> BOPAlgo_FUSE <br> BOPAlgo_CUT <br> BOPAlgo_CUT21 <br> More...
const TopoDS_Shape &	Shape1 () const
	Returns the first shape involved in this Boolean operation. More...
const TopoDS_Shape &	Shape2 () const
	Returns the second shape involved in this Boolean operation. More...
BOPAlgo_Operation	Operation () const
	Returns the type of Boolean Operation that has been performed. More...
Standard_Boolean	FuseEdges () const
	Returns the flag of edge refining More...
void	RefineEdges ()
	Fuse C1 edges More...
Standard_Boolean	BuilderCanWork () const
Standard_Integer	ErrorStatus () const
	Returns the error status of operation. <br> 0 - Ok 1 - The Object is created but Nothing is Done 2 - Null source shapes is not allowed 3 - Check types of the arguments 4 - Can not allocate memory for the DSFiller 5 - The Builder can not work with such types of arguments 6 - Unknown operation is not allowed 7 - Can not allocate memory for the Builder 100 - See the Builder's ErrorStatus More...
virtual const TopTools_ListOfShape &	Modified (const TopoDS_Shape &aS)
	Returns the list of shapes modified from the shape <S>. More...
virtual Standard_Boolean	IsDeleted (const TopoDS_Shape &aS)
	Returns true if the shape S has been deleted. The <br> result shape of the operation does not contain the shape S. More...
virtual const TopTools_ListOfShape &	Generated (const TopoDS_Shape &S)
	Returns the list of shapes generated from the shape <S>. For use in BRepNaming. More...
virtual Standard_Boolean	HasModified () const
	Returns true if there is at least one modified shape. For use in BRepNaming. More...
virtual Standard_Boolean	HasGenerated () const
	Returns true if there is at least one generated shape. For use in BRepNaming. More...
virtual Standard_Boolean	HasDeleted () const
	Returns true if there is at least one deleted shape. For use in BRepNaming. More...
void	Destroy ()
virtual	~BRepAlgoAPI_BooleanOperation ()
const TopTools_ListOfShape &	SectionEdges ()
	Returns a list of section edges. <br> The edges represent the result of intersection between arguments of Boolean Operation. They are computed during operation execution. More...
Public Member Functions inherited from BRepBuilderAPI_MakeShape
virtual void	Delete ()
virtual	~BRepBuilderAPI_MakeShape ()
const TopoDS_Shape &	Shape () const
	Returns a shape built by the shape construction algorithm. <br> Raises exception StdFail_NotDone if the shape was not built. More...
	operator TopoDS_Shape () const
Public Member Functions inherited from BRepBuilderAPI_Command
virtual	~BRepBuilderAPI_Command ()
virtual Standard_Boolean	IsDone () const
void	Check () const
	Raises NotDone if done is false. More...

Additional Inherited Members
Protected Member Functions inherited from BRepAlgoAPI_BooleanOperation
	BRepAlgoAPI_BooleanOperation (const TopoDS_Shape &S1, const TopoDS_Shape &S2, const BOPAlgo_Operation anOperation)
	Prepares the operations for S1 and S2. More...
	BRepAlgoAPI_BooleanOperation (const TopoDS_Shape &S1, const TopoDS_Shape &S2, const BOPAlgo_PaveFiller &aDSF, const BOPAlgo_Operation anOperation)
	Prepares the operations for S1 and S2. More...
Standard_Boolean	PrepareFiller ()
Protected Member Functions inherited from BRepBuilderAPI_MakeShape
	BRepBuilderAPI_MakeShape ()
Protected Member Functions inherited from BRepBuilderAPI_Command
	BRepBuilderAPI_Command ()
	Set done to False. More...
void	Done ()
	Set done to true. More...
void	NotDone ()
	Set done to false. More...
Protected Attributes inherited from BRepAlgoAPI_BooleanOperation
TopoDS_Shape	myS1
TopoDS_Shape	myS2
Standard_Boolean	myBuilderCanWork
BOPAlgo_Operation	myOperation
Standard_Integer	myErrorStatus
BOPAlgo_PPaveFiller	myDSFiller
BOPAlgo_PBOP	myBuilder
Protected Attributes inherited from BRepBuilderAPI_MakeShape
TopoDS_Shape	myShape
TopTools_ListOfShape	myGenerated

Detailed Description

Computes the intersection of two shapes or geometries.
Geometries can be surfaces of planes.
Geometries are converted to faces
When a geometry has been converted to
topology the created shape can be found using
the methods Shape1 and Shape2 inherited from the class BooleanOperation.
The result (Shape() method) is a compound containing
edges built on intersection curves.
By default, the section is performed immediatly in
class constructors, with default values :

• geometries built are NOT approximated.
  
• PCurves are NOT computed on both parts.
  Example : giving two shapes S1,S2 accessing faces,
  let compute the section edges R on S1,S2,
  performing approximation on new curves,
  performing PCurve on part 1 but not on part 2 :
  Standard_Boolean PerformNow = Standard_False;
  BRepBoolAPI_Section S(S1,S2,PerformNow);
  S.ComputePCurveOn1(Standard_True);
  S.Approximation(Standard_True);
  S.Build();
  TopoDS_Shape R = S.Shape();
  On Null Shapes of geometries, NotDone() is called.
  

Constructor & Destructor Documentation

BRepAlgoAPI_Section::BRepAlgoAPI_Section	(	const TopoDS_Shape &	S1,
		const TopoDS_Shape &	S2,
		const BOPAlgo_PaveFiller &	aDSF,
		const Standard_Boolean	PerformNow = Standard_True
	)

virtual BRepAlgoAPI_Section::~BRepAlgoAPI_Section ( )

inlinevirtual

BRepAlgoAPI_Section::BRepAlgoAPI_Section	(	const TopoDS_Shape &	Sh1,
		const TopoDS_Shape &	Sh2,
		const Standard_Boolean	PerformNow = Standard_True
	)

see upper

BRepAlgoAPI_Section::BRepAlgoAPI_Section	(	const TopoDS_Shape &	Sh,
		const gp_Pln &	Pl,
		const Standard_Boolean	PerformNow = Standard_True
	)

see upper

BRepAlgoAPI_Section::BRepAlgoAPI_Section	(	const TopoDS_Shape &	Sh,
		const Handle< Geom_Surface > &	Sf,
		const Standard_Boolean	PerformNow = Standard_True
	)

see upper

BRepAlgoAPI_Section::BRepAlgoAPI_Section	(	const Handle< Geom_Surface > &	Sf,
		const TopoDS_Shape &	Sh,
		const Standard_Boolean	PerformNow = Standard_True
	)

see upper

BRepAlgoAPI_Section::BRepAlgoAPI_Section	(	const Handle< Geom_Surface > &	Sf1,
		const Handle< Geom_Surface > &	Sf2,
		const Standard_Boolean	PerformNow = Standard_True
	)

 This and the above classes construct a framework for <br>

computing the section lines of:

• two shapes Sh1 and Sh2, or
  
• shape Sh and plane Pl, or
  
• shape Sh and surface Sf, or
  
• surface Sf and shape Sh, or
  
• two surfaces Sf1 and Sf2,
  and builds a result if PerformNow equals true, its
  default value. If PerformNow equals false, the intersection
  will be computed later by the function Build.
  The constructed shape will be returned by the function Shape.
  This is a compound object composed of edges. These
  intersection edges may be built:
  
• on new intersection lines, or
  
• on coincident portions of edges in the two intersected shapes.
  These intersection edges are independent: they are not
  chained or grouped in wires. If no intersection edge exists, the
  result is an empty compound object.
  Note that other objects than TopoDS_Shape shapes involved in
  these syntaxes are converted into faces or shells before
  performing the computation of the intersection. A shape
  resulting from this conversion can be retrieved with the
  function Shape1 or Shape2.
  Parametric 2D curves on intersection edges
  No parametric 2D curve (pcurve) is defined for each elementary
  edge of the result. To attach such parametric curves to the
  constructed edges you may use a constructor with the PerformNow
  flag equal to false; then you use:
  
• the function ComputePCurveOn1 to ask for
  the additional computation of a pcurve in the parametric
  space of the first shape,
  
• the function ComputePCurveOn2 to ask for
  the additional computation of a pcurve in the parametric
  space of the second shape, in the end,
  
• the function Build to construct the result.
  Approximation of intersection edges
  The underlying 3D geometry attached to each elementary edge
  of the result is:
  
• analytic where possible, provided the corresponding
  geometry corresponds to a type of analytic curve
  defined in the Geom package; for example, the intersection
  of a cylindrical shape with a plane gives an ellipse or a circle;
  
• or elsewhere, given as a succession of points grouped
  together in a BSpline curve of degree 1.
  If you prefer to have an attached 3D geometry which is a
  BSpline approximation of the computed set of points on
  computed elementary intersection edges whose underlying geometry
  is not analytic, you may use a constructor with the PerformNow
  flag equal to false. Then you use:
  
• the function Approximation to ask for this
  computation option, and
  
• the function Build to construct the result.
  
• Note that as a result, approximations will only be
  computed on edges built on new intersection lines.
  
• Example
  You may also combine these computation options. In the following example:
  
• each elementary edge of the computed intersection,
  built on a new intersection line, which does not
  correspond to an analytic Geom curve, will be approximated by
  a BSpline curve whose degree is not greater than 8.
  
• each elementary edge built on a new intersection line, will have:
  
• a pcurve in the parametric space of the intersected face of shape S1,
  
• no pcurve in the parametric space of the intersected face of shape S2.
  // TopoDS_Shape S1 = ... , S2 = ... ;
  Standard_Boolean PerformNow = Standard_False;
  BRepAlgoAPI_Section S ( S1, S2, PerformNow );
  S.ComputePCurveOn1 (Standard_True);
  S.Approximation (Standard_True);
  S.Build();
  TopoDS_Shape R = S.Shape();
  

Member Function Documentation

void BRepAlgoAPI_Section::Approximation

(

const Standard_Boolean

B

)

 Defines an option for computation <br>

of further intersections. This computation will be performed by
the function Build in this framework.
By default, the underlying 3D geometry attached to each
elementary edge of the result of a computed intersection is:

• analytic where possible, provided the corresponding
  geometry corresponds to a type of analytic curve defined in
  the Geom package; for example the intersection of a
  cylindrical shape with a plane gives an ellipse or a circle;
  
• or elsewhere, given as a succession of points grouped
  together in a BSpline curve of degree 1. If Approx equals
  true, when further computations are performed in this framework
  with the function Build, these edges will have an attached 3D
  geometry which is a BSpline approximation of the computed
  set of points.
  Note that as a result, approximations will be computed
  on edges built only on new intersection lines.
  

void BRepAlgoAPI_Section::Build ( )

virtual

  Performs the computation of <br>

section lines between two parts defined at the time of
construction of this framework or reinitialized with the Init1 and
Init2 functions.
The constructed shape will be returned by the function Shape.
This is a compound object composed of edges. These
intersection edges may be built:

• on new intersection lines, or
  
• on coincident portions of edges in the two intersected shapes.
  These intersection edges are independent: they are not chained
  or grouped into wires.
  If no intersection edge exists, the result is an empty compound object.
  The shapes involved in the construction of section lines can
  be retrieved with the function Shape1 or Shape2. Note that other
  objects than TopoDS_Shape shapes given as arguments at the
  construction time of this framework, or to the Init1 or
  Init2 function, are converted into faces or shells before
  performing the computation of the intersection.
  Parametric 2D curves on intersection edges
  No parametric 2D curve (pcurve) is defined for the elementary
  edges of the result. To attach parametric curves like this to
  the constructed edges you have to use:
  
• the function
  ComputePCurveOn1 to ask for the additional computation of a
  pcurve in the parametric space of the first shape,
  
• the function
  ComputePCurveOn2 to ask for the additional computation of a
  pcurve in the parametric space of the second shape.
  This must be done before calling this function.
  Approximation of intersection edges
  The underlying 3D geometry attached to each elementary edge of the result is:
  
• analytic (where possible) provided the corresponding
  geometry corresponds to a type of analytic curve defined in
  the Geom package; for example, the intersection of a
  cylindrical shape with a plane gives an ellipse or a circle; or
  
• elsewhere, given as a succession of points grouped
  together in a BSpline curve of degree 1.
  If, on computed elementary intersection edges whose
  underlying geometry is not analytic, you prefer to have an
  attached 3D geometry which is a Bspline approximation of the
  computed set of points, you have to use the function Approximation
  to ask for this computation option before calling this function.
  You may also have combined these computation options: look at the
  example given above to illustrate the use of the constructors.
  

Reimplemented from BRepAlgoAPI_BooleanOperation.

void BRepAlgoAPI_Section::ComputePCurveOn1

(

const Standard_Boolean

B

)

Indicates if the Pcurve must be (or not) performed on first part.

void BRepAlgoAPI_Section::ComputePCurveOn2

(

const Standard_Boolean

B

)

 Define options for the computation of further <br>

intersections, which will be performed by the function Build
in this framework.
By default, no parametric 2D curve (pcurve) is defined for the
elementary edges of the result. If ComputePCurve1 equals true,
further computations performed in this framework with the function
Build will attach an additional pcurve in the parametric space of
the first shape to the constructed edges.
If ComputePCurve2 equals true, the additional pcurve will be
attached to the constructed edges in the parametric space of the
second shape.
These two functions may be used together.

Standard_Boolean BRepAlgoAPI_Section::HasAncestorFaceOn1	(	const TopoDS_Shape &	E,
		TopoDS_Shape &	F
	)		const

get the face of the first part giving section edge <E>.
Returns True on the 3 following conditions :
1/ <E> is an edge returned by the Shape() method.
2/ First part of section performed is a shape.
3/ <E> is built on a intersection curve (i.e <E>
is not the result of common edges)
When False, F remains untouched.

Standard_Boolean BRepAlgoAPI_Section::HasAncestorFaceOn2	(	const TopoDS_Shape &	E,
		TopoDS_Shape &	F
	)		const

  Identifies the ancestor faces of <br>

the intersection edge E resulting from the last
computation performed in this framework, that is, the faces of
the two original shapes on which the edge E lies:

• HasAncestorFaceOn1 gives the ancestor face in the first shape, and
  
• HasAncestorFaceOn2 gives the ancestor face in the second shape.
  These functions return true if an ancestor face F is found, or false if not.
  An ancestor face is identifiable for the edge E if the following
  conditions are satisfied:
  
• the first part on which this algorithm performed its
  last computation is a shape, that is, it was not given as
  a surface or a plane at the time of construction of this
  algorithm or at a later time by the Init1 function,
  
• E is one of the elementary edges built by the
  last computation of this section algorithm.
  To use these functions properly, you have to test the returned
  Boolean value before using the ancestor face: F is significant
  only if the returned Boolean value equals true.
  

void BRepAlgoAPI_Section::Init1

(

const TopoDS_Shape &

S1

)

initialize first part

void BRepAlgoAPI_Section::Init1

(

const gp_Pln &

Pl

)

initialize first part

void BRepAlgoAPI_Section::Init1

(

const Handle< Geom_Surface > &

Sf

)

initialize first part

void BRepAlgoAPI_Section::Init2

(

const TopoDS_Shape &

S2

)

initialize second part

void BRepAlgoAPI_Section::Init2

(

const gp_Pln &

Pl

)

initialize second part

void BRepAlgoAPI_Section::Init2

(

const Handle< Geom_Surface > &

Sf

)

 Reinitializes the first and the <br>

second parts on which this algorithm is going to perform
the intersection computation. This is done with either: the
surface Sf, the plane Pl or the shape Sh.
You use the function Build to construct the result.

---

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

• BRepAlgoAPI_Section.hxx