MbOrientedEdge Oriented Face Edge

Class MbOrientedEdge is declared in file topology.h.

Oriented edge MbOrientedEdge is a derived class of the topological object MbTopItem and describes a portion of a face boundary. The data structure of an oriented edge contains a face edge 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.

Fig. 1

In the general case, a face edge 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.