manufacturingtoolkit.CadExMTK.ModelData_Face Class Reference

Face Face.hxx cadex/ModelData/Face.hxx. More...

Inheritance diagram for manufacturingtoolkit.CadExMTK.ModelData_Face:

Public Member Functions
	__init__ (self, *args)
	ParametricDomain (self)
	Append (self, *args)
	Adds a wire to the face.
	Surface (self)
	Returns underlying surface.
	OuterWire (self)
	Returns outer wire.
	Triangulation (self)
	Returns triangulation of the face.
Public Member Functions inherited from manufacturingtoolkit.CadExMTK.ModelData_Shape
	Type (self)
	Returns a shape type.
	Orientation (self)
	Returns orientation flag.
	Reversed (self)
	Returns a shape that shares the same geometry and subshape graph but has opposite orientation.
	Oriented (self, theOrientation)
	Returns a shape that shares the same geometry and subshape graph and has specified orientation.
	IsEqual (self, theOther)
	Returns true if the shape shares the same geometry and subshape graph, and has equal orientation.
	IsSame (self, theOther)
	Returns true if the shape shares the same geometry and subshape graph.
	SetName (self, theName)
	Sets the name.
	Name (self)
	Returns the name.
	AddAssociatedPMI (self, *args)
	AssociatedPMI (self)
	Returns the PMI elements.
Public Member Functions inherited from manufacturingtoolkit.CadExMTK.BaseObject
	Id (self)
	Return unique identifier of public object.
	IsNull (self)

Static Public Member Functions
	Cast (*args)
	Overload 1: Cast operator.
	CompareType (theObject)
	Check the type of object.

Detailed Description

Face Face.hxx cadex/ModelData/Face.hxx.

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

__init__()

manufacturingtoolkit.CadExMTK.ModelData_Face.__init__	(		self,
		*	args )

Reimplemented from manufacturingtoolkit.CadExMTK.ModelData_Shape.

Member Function Documentation

Cast()

manufacturingtoolkit.CadExMTK.ModelData_Face.Cast ( * args )

static

Overload 1: Cast operator.

|

Overload 2: Cast operator.

Reimplemented from manufacturingtoolkit.CadExMTK.ModelData_Shape.

CompareType()

manufacturingtoolkit.CadExMTK.ModelData_Face.CompareType ( theObject )

static

Check the type of object.

Returns true if the specified object is this class type.

Reimplemented from manufacturingtoolkit.CadExMTK.ModelData_Shape.

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

• CadExMTK.py