.. role:: blue
   :class: blue

MbOrientedEdge Oriented Face Edge
=================================
.. _MbOrientedEdge_Oriented_Face_Edge_:

.. версия ядра: 

Class :blue:`MbOrientedEdge` is declared in file *topology.h*.

Oriented edge :blue:`MbOrientedEdge` is a derived class of the topological object :ref:`MbTopItem <MbTopItem_Topological_Object_>` and describes a portion of a face boundary. The data structure of an oriented edge contains a face edge :blue:`MbCurveEdge` *curveEdge* and a flag indicating coincidence of the face edge direction with the oriented edge direction and, accordingly, with the face loop direction *orientation*.

If the direction of the face edge *curveEdge* coincides with the loop direction, then in the loop of this face the corresponding oriented edge has flag *orientation* = true. If the direction of the face edge *curveEdge* does not coincide with the loop direction, then in the loop of this face the corresponding oriented edge has flag *orientation* = false. Fig. 1 shows two oriented edges constructed on the same face edge *curveEdge*.

.. figure:: /MODELER/TOPOLOGICAL_OBJECTS/pictures/O.7.7.1.png
   :width: 12cm
   :align: center

   Fig. 1

In the general case, a face edge :blue:`MbCurveEdge` belongs to two loops; these loops belong to the faces joined by the edge. In one loop, the face edge enters with orientation flag *orientation* = true, this face is located on the left of the edge and the data field **facePlus** points to it. In the other loop, the face edge enters with orientation flag *orientation* = false, this face is located on the right of the edge and the data field **faceMinus** points to it. Thus adjacent faces and the edges connecting them are linked to each other.