// find edge by 2 vertices
TopoDS_Shape V1 = edge;
TopoDS_Shape V2 = myHelper->GetSubShapeByNode( node, meshDS );
- if ( V2.ShapeType() == TopAbs_VERTEX && !V2.IsSame( V1 ))
+ if ( !V2.IsNull() && V2.ShapeType() == TopAbs_VERTEX && !V2.IsSame( V1 ))
{
TopoDS_Shape ancestor = myHelper->GetCommonAncestor( V1, V2, *myHelper->GetMesh(), TopAbs_EDGE);
if ( !ancestor.IsNull() )