cadex::ModelData::Face Class Reference

Defines a topological face. More...

#include <cadex/ModelData/Face.hxx>

Inheritance diagram for cadex::ModelData::Face:

Public Member Functions
	Face (const Geom::Surface &theSurface, bool theMakeWire=false)
	Constructor.
	Face (const Geom::Surface &theSurface, const Wire &theWire)
	Constructor.
	Face (const Geom::Surface &theSurface, double theUMin, double theUMax, double theVMin, double theVMax)
	Constructor.
void	ParametricDomain (double &theUMin, double &theUMax, double &theVMin, double &theVMax) const
bool	Append (const Wire &theWire)
	Adds a wire to the face.
bool	Append (const std::vector< Wire > &theWires)
	Adds a wires to the face.
Geom::Surface	Surface () const
	Returns underlying surface.
Wire	OuterWire () const
	Returns outer wire.
IndexedTriangleSet	Triangulation () const
	Returns triangulation of the face.
Public Member Functions inherited from cadex::ModelData::Shape
ShapeType	Type () const
	Returns a shape type. For a null object returns Undefined.
ShapeOrientation	Orientation () const
	Returns orientation flag.
Shape	Reversed () const
	Returns a shape that shares the same geometry and subshape graph but has opposite orientation.
Shape	Oriented (ShapeOrientation theOrientation) const
	Returns a shape that shares the same geometry and subshape graph and has specified orientation.
bool	IsEqual (const Shape &theOther) const
	Returns true if the shape shares the same geometry and subshape graph, and has equal orientation.
bool	IsSame (const Shape &theOther) const
	Returns true if the shape shares the same geometry and subshape graph.
void	SetName (const UTF16String &theName)
UTF16String	Name () const
Public Member Functions inherited from cadex::BaseObject
size_t	Id () const
	Return unique identifier of public object.
internal::BaseObjectImpl *	Impl () const
bool	IsNull () const
	operator bool () const
template<typename T >
bool	IsOfType () const
template<typename T >
T *	Impl () const
	Reserved for internal use.

Static Public Member Functions
static const Face &	Cast (const Shape &theShape)
	Cast operator.
static Face &	Cast (Shape &theShape)
	Cast operator.
static bool	CompareType (const BaseObject &theObject)
	Check the type of object. Returns true if the specified object is this class type.
Static Public Member Functions inherited from cadex::ModelData::Shape
static bool	CompareType (const BaseObject &theObject)
	Check the type of object. Returns true if the specified object is this class type.

Additional Inherited Members
Public Types inherited from cadex::BaseObject
typedef std::shared_ptr< internal::BaseObjectImpl >	ImplType
Protected Member Functions inherited from cadex::ModelData::Shape
	Shape (const ImplType &theImpl)
Protected Member Functions inherited from cadex::BaseObject
	BaseObject (const ImplType &theImpl)

Detailed Description

Defines a topological face.

The following image depicts an example of a face:

Face

Face resides on a geometrical surface (returned by Surface()) and is bounded by one or several wires. A face must always have at least one explicit outer wire even if it corresponds to a naturally bounded surface (e.g. torus or a sphere).

Orientation() defines whether face normal matches the normal of the underlying surface, or is opposite to it.

Face Boundaries

Face wires must always be closed, both in 3D and in 2D (i.e. parametric space of the underlying surface). Therefore a face lying on a periodical surface on its full period must have an explicit seam-edge (an edge corresponding to surface boundaries).

A face outer wire can be distinguished using the OuterWire() method.

Face wires must be oriented such that they define a closed portion of material. If to look in the direction opposite to a surface normal, p-curves of an outer wire (taking into account edge orientations) must be oriented counter-clockwise, and p-curve of inner wires (if present) - clockwise. This ensures that the face has a finite area.

The following image depicts an example of face with two wires and p-curves in parametric space of the face surface. P-curves of edges with forward orientation are displayed in green, p-curves of edges with reversed orientation are displayed in red:

Face with two wires

P-curves in surface parametric space

Note

Own face orientation must be ignored when defining correct contour orientation (unlike, for instance, ACIS or Parasolid kernels which do take face orientation into account).

The following code snippet demonstrates how to iterate over face edges p-curves:

ModelData::Face aFace;
 
// always use forward orientation when analyzing pcurves orientation
ModelData::Face aFwdFace = ModelData::Face::Cast (aFace.Oriented (ModelData::ShapeOrientation::Forward));
ModelData::Wire anOuterWire = aFwdFace.OuterWire();
 
ModelData::ShapeIterator i (aFwdFace);
while (i.HasNext()) {
    const ModelData::Shape& aWire = i.Next(); // wire
    assert (aWire.Type() == ModelData::ShapeType::Wire);
 
    if (aWire.IsSame (anOuterWire)) {
        // we are exploring an outer wire
    } else {
        // we are exploring a hole
    }
 
    ModelData::ShapeIterator j (aWire);
    while (j.HasNext()) {
        const ModelData::Shape& aShape = j.Next(); // edge
        const ModelData::Edge&  anEdge = ModelData::Edge::Cast (aShape);
 
        double        aF, aL;
        Geom::Curve2d aPCurve = anEdge.PCurve (aFwdFace, aF, aL);
 
        if (anEdge.Orientation() == ModelData::ShapeOrientation::Forward) {
            // face material is on the left from the pcurve
        } else {
            // face material is on the right from the pcurve
        }
    }
}

2D Bounding Box

Face p-curves define a closed contour (or a set of contours in the case of face with holes) in surface parametric space. A 2D bounding box in this surface parametric space can be returned using the Measurements::ComputeBoundingBox() method (its overload accepting ModelData::Face). The following images demonstrate a face lying on a cylindrical surface and its 2D contour and bounding box:

Face on cylindrical surface

2D bounding box

The following example demonstrates how to retrieve this bounding box. Note aHeight below would designate a 3D length of this cylindrical face and if it occupied entire U-range of the cylindrical surface (Geom::CylindricalSurface) then it would correspond to a cylinder's height:

ModelData::Face aFace;
ModelData::Box aBox;
Measurements::ComputeBoundingBox(aFace, Geom::Transformation(), aBox);
double aHeight = aBox.YRange(); // cylindrical surface is parametrized by length in V-range

Constructor & Destructor Documentation

Face() [1/3]

cadex::ModelData::Face::Face	(	const Geom::Surface &	Surface,
		bool	theMakeWire = false )

Constructor.

Creates a face on entire surface's definition domain:

Constructing face from surface

The surface must have bounded definition domain (see ModelData::Surface::Domain()). This is the case for instance for Geom::BSplineSurface.

theMakeWire specifies whether the wire must be automatically constructed and added to the face.

Face() [2/3]

cadex::ModelData::Face::Face	(	const Geom::Surface &	theSurface,
		const Wire &	theWire )

Constructor.

Creates a face from a surface and explicitly defined wire:

Constructing face from surface and wire

The wire's edge must lie on a surface (within proximity of their tolerances).

Face() [3/3]

cadex::ModelData::Face::Face	(	const Geom::Surface &	theSurface,
		double	theUMin,
		double	theUMax,
		double	theVMin,
		double	theVMax )

Constructor.

Creates a face from a surface and its parametric definition domain:

Input surface

Surface definition domain

The parameters must be within surface's definition domain (see ModelData_Surface::Domain()) unless it is periodic. theUMax must be greater than theUMin by at least 1e-9.

Member Function Documentation

Append() [1/2]

bool cadex::ModelData::Face::Append

(

const std::vector< Wire > &

theWires

)

Adds a wires to the face.

There must be single outer wire and zero, one or more inner wires (i.e. holes). It is strongly recommended (although not required) that the first wire being added is an outer wire.

Returns false if one of the theWires is null and true otherwise.

Append() [2/2]

bool cadex::ModelData::Face::Append

(

const Wire &

theWire

)

Adds a wire to the face.

There must be single outer wire and zero, one or more inner wires (i.e. holes). It is strongly recommended (although not required) that the first wire being added is an outer wire.

Returns false if theWire is null and true otherwise.

Cast() [1/2]

const Face & cadex::ModelData::Face::Cast ( const Shape & theShape )

static

Cast operator.

Casts theShape to a face. If theShape is not a face then behavior is undefined (assert will be thrown in debug mode).

Cast() [2/2]

Face & cadex::ModelData::Face::Cast ( Shape & theShape )

static

Cast operator.

Casts theShape to a face. If theShape is not a face then behavior is undefined (assert will be thrown in debug mode).

Triangulation()

IndexedTriangleSet cadex::ModelData::Face::Triangulation

(

)

const

Returns triangulation of the face.

An empty object may be returned.