return true;
}
+//================================================================================
+/*!
+ * \brief Find out elements orientation on a geometrical face
+ * \param theFace - The face correctly oriented in the shape being meshed
+ * \retval bool - true if the face normal and the normal of first element
+ * in the correspoding submesh point in different directions
+ */
+//================================================================================
+
+bool SMESH_MesherHelper::IsReversedSubMesh (const TopoDS_Face& theFace)
+{
+ if ( theFace.IsNull() )
+ return false;
+
+ // find out orientation of a meshed face
+ int faceID = GetMeshDS()->ShapeToIndex( theFace );
+ TopoDS_Shape aMeshedFace = GetMeshDS()->IndexToShape( faceID );
+ bool isReversed = ( theFace.Orientation() != aMeshedFace.Orientation() );
+
+ const SMESHDS_SubMesh * aSubMeshDSFace = GetMeshDS()->MeshElements( faceID );
+ if ( !aSubMeshDSFace )
+ return isReversed;
+
+ // find an element with a good normal
+ gp_Vec Ne;
+ bool normalOK = false;
+ gp_XY uv;
+ SMDS_ElemIteratorPtr iteratorElem = aSubMeshDSFace->GetElements();
+ while ( !normalOK && iteratorElem->more() ) // loop on elements on theFace
+ {
+ const SMDS_MeshElement* elem = iteratorElem->next();
+ if ( elem && elem->NbCornerNodes() > 2 )
+ {
+ SMESH_TNodeXYZ nPnt[3];
+ SMDS_ElemIteratorPtr nodesIt = elem->nodesIterator();
+ for ( int iN = 0; nodesIt->more() && iN < 3; ++iN) // loop on nodes
+ nPnt[ iN ] = nodesIt->next();
+
+ // compute normal
+ gp_Vec v01( nPnt[0], nPnt[1] ), v02( nPnt[0], nPnt[2] );
+ if ( v01.SquareMagnitude() > RealSmall() &&
+ v02.SquareMagnitude() > RealSmall() )
+ {
+ Ne = v01 ^ v02;
+ if (( normalOK = ( Ne.SquareMagnitude() > RealSmall() )))
+ uv = GetNodeUV( theFace, nPnt[0]._node, nPnt[2]._node, &normalOK );
+ }
+ }
+ }
+ if ( !normalOK )
+ return isReversed;
+
+ // face normal at node position
+ TopLoc_Location loc;
+ Handle(Geom_Surface) surf = BRep_Tool::Surface( theFace, loc );
+ // if ( surf.IsNull() || surf->Continuity() < GeomAbs_C1 )
+ // some surfaces not detected as GeomAbs_C1 are nevertheless correct for meshing
+ if ( surf.IsNull() || surf->Continuity() < GeomAbs_C0 )
+ {
+ if (!surf.IsNull())
+ MESSAGE("surf->Continuity() < GeomAbs_C1 " << (surf->Continuity() < GeomAbs_C1));
+ return isReversed;
+ }
+ gp_Vec d1u, d1v; gp_Pnt p;
+ surf->D1( uv.X(), uv.Y(), p, d1u, d1v );
+ gp_Vec Nf = (d1u ^ d1v).Transformed( loc );
+
+ if ( theFace.Orientation() == TopAbs_REVERSED )
+ Nf.Reverse();
+
+ return Ne * Nf < 0.;
+}
+
//=======================================================================
//function : Count
//purpose : Count nb of sub-shapes
