コード例 #1
0
bool NETGENPlugin_NETGEN_3D::Compute(SMESH_Mesh&         aMesh,
                                     const TopoDS_Shape& aShape)
{
    MESSAGE("NETGENPlugin_NETGEN_3D::Compute with maxElmentsize = " << _maxElementVolume);

    SMESHDS_Mesh* meshDS = aMesh.GetMeshDS();

    const int invalid_ID = -1;

    SMESH::Controls::Area areaControl;
    SMESH::Controls::TSequenceOfXYZ nodesCoords;

    // -------------------------------------------------------------------
    // get triangles on aShell and make a map of nodes to Netgen node IDs
    // -------------------------------------------------------------------

    SMESH_MesherHelper helper(aMesh);
    SMESH_MesherHelper* myTool = &helper;
    bool _quadraticMesh = myTool->IsQuadraticSubMesh(aShape);

    typedef map< const SMDS_MeshNode*, int, TIDCompare > TNodeToIDMap;
    TNodeToIDMap nodeToNetgenID;
    list< const SMDS_MeshElement* > triangles;
    list< bool >                    isReversed; // orientation of triangles

    TopAbs_ShapeEnum mainType = aMesh.GetShapeToMesh().ShapeType();
    bool checkReverse = ( mainType == TopAbs_COMPOUND || mainType == TopAbs_COMPSOLID );

    // for the degeneraged edge: ignore all but one node on it;
    // map storing ids of degen edges and vertices and their netgen id:
    map< int, int* > degenShapeIdToPtrNgId;
    map< int, int* >::iterator shId_ngId;
    list< int > degenNgIds;

    StdMeshers_QuadToTriaAdaptor Adaptor;
    Adaptor.Compute(aMesh,aShape);

    for (TopExp_Explorer exp(aShape,TopAbs_FACE); exp.More(); exp.Next())
    {
        const TopoDS_Shape& aShapeFace = exp.Current();
        const SMESHDS_SubMesh * aSubMeshDSFace = meshDS->MeshElements( aShapeFace );
        if ( aSubMeshDSFace )
        {
            bool isRev = false;
            if ( checkReverse && helper.NbAncestors(aShapeFace, aMesh, aShape.ShapeType()) > 1 )
                // IsReversedSubMesh() can work wrong on strongly curved faces,
                // so we use it as less as possible
                isRev = SMESH_Algo::IsReversedSubMesh( TopoDS::Face(aShapeFace), meshDS );

            SMDS_ElemIteratorPtr iteratorElem = aSubMeshDSFace->GetElements();
            while ( iteratorElem->more() ) // loop on elements on a face
            {
                // check element
                const SMDS_MeshElement* elem = iteratorElem->next();
                if ( !elem )
                    return error( COMPERR_BAD_INPUT_MESH, "Null element encounters");
                bool isTraingle = ( elem->NbNodes()==3 || (_quadraticMesh && elem->NbNodes()==6 ));
                if ( !isTraingle ) {
                    //return error( COMPERR_BAD_INPUT_MESH,
                    //              SMESH_Comment("Not triangle element ")<<elem->GetID());
                    // using adaptor
                    const list<const SMDS_FaceOfNodes*>* faces = Adaptor.GetTriangles(elem);
                    if(faces==0) {
                        return error( COMPERR_BAD_INPUT_MESH,
                                      SMESH_Comment("Not triangles in adaptor for element ")<<elem->GetID());
                    }
                    list<const SMDS_FaceOfNodes*>::const_iterator itf = faces->begin();
                    for(; itf!=faces->end(); itf++ ) {
                        triangles.push_back( (*itf) );
                        isReversed.push_back( isRev );
                        // put triange's nodes to nodeToNetgenID map
                        SMDS_ElemIteratorPtr triangleNodesIt = (*itf)->nodesIterator();
                        while ( triangleNodesIt->more() ) {
                            const SMDS_MeshNode * node =
                                static_cast<const SMDS_MeshNode *>(triangleNodesIt->next());
                            if(myTool->IsMedium(node))
                                continue;
                            nodeToNetgenID.insert( make_pair( node, invalid_ID ));
                        }
                    }
                }
                else {
                    // keep a triangle
                    triangles.push_back( elem );
                    isReversed.push_back( isRev );
                    // put elem nodes to nodeToNetgenID map
                    SMDS_ElemIteratorPtr triangleNodesIt = elem->nodesIterator();
                    while ( triangleNodesIt->more() ) {
                        const SMDS_MeshNode * node =
                            static_cast<const SMDS_MeshNode *>(triangleNodesIt->next());
                        if(myTool->IsMedium(node))
                            continue;
                        nodeToNetgenID.insert( make_pair( node, invalid_ID ));
                    }
                }
#ifdef _DEBUG_
                // check if a trainge is degenerated
                areaControl.GetPoints( elem, nodesCoords );
                double area = areaControl.GetValue( nodesCoords );
                if ( area <= DBL_MIN ) {
                    MESSAGE( "Warning: Degenerated " << elem );
                }
#endif
            }
            // look for degeneraged edges and vetices
            for (TopExp_Explorer expE(aShapeFace,TopAbs_EDGE); expE.More(); expE.Next())
            {
                TopoDS_Edge aShapeEdge = TopoDS::Edge( expE.Current() );
                if ( BRep_Tool::Degenerated( aShapeEdge ))
                {
                    degenNgIds.push_back( invalid_ID );
                    int* ptrIdOnEdge = & degenNgIds.back();
                    // remember edge id
                    int edgeID = meshDS->ShapeToIndex( aShapeEdge );
                    degenShapeIdToPtrNgId.insert( make_pair( edgeID, ptrIdOnEdge ));
                    // remember vertex id
                    int vertexID = meshDS->ShapeToIndex( TopExp::FirstVertex( aShapeEdge ));
                    degenShapeIdToPtrNgId.insert( make_pair( vertexID, ptrIdOnEdge ));
                }
            }
        }
    }
    // ---------------------------------
    // Feed the Netgen with surface mesh
    // ---------------------------------

    int Netgen_NbOfNodes = 0;
    int Netgen_param2ndOrder = 0;
    double Netgen_paramFine = 1.;
    double Netgen_paramSize = pow( 72, 1/6. ) * pow( _maxElementVolume, 1/3. );

    double Netgen_point[3];
    int Netgen_triangle[3];
    int Netgen_tetrahedron[4];

    Ng_Init();

    Ng_Mesh * Netgen_mesh = Ng_NewMesh();

    // set nodes and remember thier netgen IDs
    bool isDegen = false, hasDegen = !degenShapeIdToPtrNgId.empty();
    TNodeToIDMap::iterator n_id = nodeToNetgenID.begin();
    for ( ; n_id != nodeToNetgenID.end(); ++n_id )
    {
        const SMDS_MeshNode* node = n_id->first;

        // ignore nodes on degenerated edge
        if ( hasDegen ) {
            int shapeId = node->GetPosition()->GetShapeId();
            shId_ngId = degenShapeIdToPtrNgId.find( shapeId );
            isDegen = ( shId_ngId != degenShapeIdToPtrNgId.end() );
            if ( isDegen && *(shId_ngId->second) != invalid_ID ) {
                n_id->second = *(shId_ngId->second);
                continue;
            }
        }
        Netgen_point [ 0 ] = node->X();
        Netgen_point [ 1 ] = node->Y();
        Netgen_point [ 2 ] = node->Z();
        Ng_AddPoint(Netgen_mesh, Netgen_point);
        n_id->second = ++Netgen_NbOfNodes; // set netgen ID

        if ( isDegen ) // all nodes on a degen edge get one netgen ID
            *(shId_ngId->second) = n_id->second;
    }

    // set triangles
    list< const SMDS_MeshElement* >::iterator tria = triangles.begin();
    list< bool >::iterator                 reverse = isReversed.begin();
    for ( ; tria != triangles.end(); ++tria, ++reverse )
    {
        int i = 0;
        SMDS_ElemIteratorPtr triangleNodesIt = (*tria)->nodesIterator();
        while ( triangleNodesIt->more() ) {
            const SMDS_MeshNode * node =
                static_cast<const SMDS_MeshNode *>(triangleNodesIt->next());
            if(myTool->IsMedium(node))
                continue;
            Netgen_triangle[ *reverse ? 2 - i : i ] = nodeToNetgenID[ node ];
            ++i;
        }
        if ( !hasDegen ||
                // ignore degenerated triangles, they have 2 or 3 same ids
                (Netgen_triangle[0] != Netgen_triangle[1] &&
                 Netgen_triangle[0] != Netgen_triangle[2] &&
                 Netgen_triangle[2] != Netgen_triangle[1] ))
        {
            Ng_AddSurfaceElement(Netgen_mesh, NG_TRIG, Netgen_triangle);
        }
    }

    // -------------------------
    // Generate the volume mesh
    // -------------------------

    Ng_Meshing_Parameters Netgen_param;

    Netgen_param.secondorder = Netgen_param2ndOrder;
    Netgen_param.fineness = Netgen_paramFine;
    Netgen_param.maxh = Netgen_paramSize;

    Ng_Result status;

    try {
#if (OCC_VERSION_MAJOR << 16 | OCC_VERSION_MINOR << 8 | OCC_VERSION_MAINTENANCE) > 0x060100
        OCC_CATCH_SIGNALS;
#endif
        status = Ng_GenerateVolumeMesh(Netgen_mesh, &Netgen_param);
    }
    catch (Standard_Failure& exc) {
        error(COMPERR_OCC_EXCEPTION, exc.GetMessageString());
        status = NG_VOLUME_FAILURE;
    }
    catch (...) {
        error("Exception in Ng_GenerateVolumeMesh()");
        status = NG_VOLUME_FAILURE;
    }
    if ( GetComputeError()->IsOK() ) {
        switch ( status ) {
        case NG_SURFACE_INPUT_ERROR:
            error( status, "NG_SURFACE_INPUT_ERROR");
        case NG_VOLUME_FAILURE:
            error( status, "NG_VOLUME_FAILURE");
        case NG_STL_INPUT_ERROR:
            error( status, "NG_STL_INPUT_ERROR");
        case NG_SURFACE_FAILURE:
            error( status, "NG_SURFACE_FAILURE");
        case NG_FILE_NOT_FOUND:
            error( status, "NG_FILE_NOT_FOUND");
        };
    }

    int Netgen_NbOfNodesNew = Ng_GetNP(Netgen_mesh);

    int Netgen_NbOfTetra = Ng_GetNE(Netgen_mesh);

    MESSAGE("End of Volume Mesh Generation. status=" << status <<
            ", nb new nodes: " << Netgen_NbOfNodesNew - Netgen_NbOfNodes <<
            ", nb tetra: " << Netgen_NbOfTetra);

    // -------------------------------------------------------------------
    // Feed back the SMESHDS with the generated Nodes and Volume Elements
    // -------------------------------------------------------------------

    bool isOK = ( /*status == NG_OK &&*/ Netgen_NbOfTetra > 0 );// get whatever built
    if ( isOK )
    {
        // vector of nodes in which node index == netgen ID
        vector< const SMDS_MeshNode* > nodeVec ( Netgen_NbOfNodesNew + 1 );
        // insert old nodes into nodeVec
        for ( n_id = nodeToNetgenID.begin(); n_id != nodeToNetgenID.end(); ++n_id ) {
            nodeVec.at( n_id->second ) = n_id->first;
        }
        // create and insert new nodes into nodeVec
        int nodeIndex = Netgen_NbOfNodes + 1;
        int shapeID = meshDS->ShapeToIndex( aShape );
        for ( ; nodeIndex <= Netgen_NbOfNodesNew; ++nodeIndex )
        {
            Ng_GetPoint( Netgen_mesh, nodeIndex, Netgen_point );
            SMDS_MeshNode * node = meshDS->AddNode(Netgen_point[0],
                                                   Netgen_point[1],
                                                   Netgen_point[2]);
            meshDS->SetNodeInVolume(node, shapeID);
            nodeVec.at(nodeIndex) = node;
        }

        // create tetrahedrons
        for ( int elemIndex = 1; elemIndex <= Netgen_NbOfTetra; ++elemIndex )
        {
            Ng_GetVolumeElement(Netgen_mesh, elemIndex, Netgen_tetrahedron);
            SMDS_MeshVolume * elt = myTool->AddVolume (nodeVec.at( Netgen_tetrahedron[0] ),
                                    nodeVec.at( Netgen_tetrahedron[1] ),
                                    nodeVec.at( Netgen_tetrahedron[2] ),
                                    nodeVec.at( Netgen_tetrahedron[3] ));
            meshDS->SetMeshElementOnShape(elt, shapeID );
        }
    }

    Ng_DeleteMesh(Netgen_mesh);
    Ng_Exit();

    NETGENPlugin_Mesher::RemoveTmpFiles();

    return (status == NG_OK);
}
コード例 #2
0
bool StdMeshers_Hexa_3D::Compute(SMESH_Mesh &         aMesh,
                                 const TopoDS_Shape & aShape)// throw(SALOME_Exception)
{
  // PAL14921. Enable catching std::bad_alloc and Standard_OutOfMemory outside
  //Unexpect aCatch(SalomeException);
  MESSAGE("StdMeshers_Hexa_3D::Compute");
  SMESHDS_Mesh * meshDS = aMesh.GetMeshDS();

  // 0.  - shape and face mesh verification
  // 0.1 - shape must be a solid (or a shell) with 6 faces

  vector < SMESH_subMesh * >meshFaces;
  for (TopExp_Explorer exp(aShape, TopAbs_FACE); exp.More(); exp.Next()) {
    SMESH_subMesh *aSubMesh = aMesh.GetSubMeshContaining(exp.Current());
    ASSERT(aSubMesh);
    meshFaces.push_back(aSubMesh);
  }
  if (meshFaces.size() != 6) {
    //return error(COMPERR_BAD_SHAPE, TComm(meshFaces.size())<<" instead of 6 faces in a block");
    static StdMeshers_CompositeHexa_3D compositeHexa(-10, 0, aMesh.GetGen());
    if ( !compositeHexa.Compute( aMesh, aShape ))
      return error( compositeHexa.GetComputeError() );
    return true;
  }

  // 0.2 - is each face meshed with Quadrangle_2D? (so, with a wire of 4 edges)

  // tool for working with quadratic elements
  SMESH_MesherHelper aTool (aMesh);
  _quadraticMesh = aTool.IsQuadraticSubMesh(aShape);

  // cube structure
  typedef struct cubeStruct
  {
    TopoDS_Vertex V000;
    TopoDS_Vertex V001;
    TopoDS_Vertex V010;
    TopoDS_Vertex V011;
    TopoDS_Vertex V100;
    TopoDS_Vertex V101;
    TopoDS_Vertex V110;
    TopoDS_Vertex V111;
    faceQuadStruct* quad_X0;
    faceQuadStruct* quad_X1;
    faceQuadStruct* quad_Y0;
    faceQuadStruct* quad_Y1;
    faceQuadStruct* quad_Z0;
    faceQuadStruct* quad_Z1;
    Point3DStruct* np; // normalised 3D coordinates
  } CubeStruct;

  CubeStruct aCube;

  // bounding faces
  FaceQuadStruct* aQuads[6];
  for (int i = 0; i < 6; i++)
    aQuads[i] = 0;

  for (int i = 0; i < 6; i++)
  {
    TopoDS_Shape aFace = meshFaces[i]->GetSubShape();
    SMESH_Algo *algo = _gen->GetAlgo(aMesh, aFace);
    string algoName = algo->GetName();
    bool isAllQuad = false;
    if (algoName == "Quadrangle_2D") {
      SMESHDS_SubMesh * sm = meshDS->MeshElements( aFace );
      if ( sm ) {
        isAllQuad = true;
        SMDS_ElemIteratorPtr eIt = sm->GetElements();
        while ( isAllQuad && eIt->more() ) {
          const SMDS_MeshElement* elem =  eIt->next();
          isAllQuad = ( elem->NbNodes()==4 ||(_quadraticMesh && elem->NbNodes()==8) );
        }
      }
    }
    if ( ! isAllQuad ) {
      SMESH_ComputeErrorPtr err = ComputePentahedralMesh(aMesh, aShape);
      return ClearAndReturn( aQuads, error(err));
    }
    StdMeshers_Quadrangle_2D *quadAlgo =
      dynamic_cast < StdMeshers_Quadrangle_2D * >(algo);
    ASSERT(quadAlgo);
    try {
      aQuads[i] = quadAlgo->CheckAnd2Dcompute(aMesh, aFace, _quadraticMesh);
      if(!aQuads[i]) {
        return error( quadAlgo->GetComputeError());
      }
    }
    catch(SALOME_Exception & S_ex) {
      return ClearAndReturn( aQuads, error(COMPERR_SLM_EXCEPTION,TComm(S_ex.what()) <<
                                           " Raised by StdMeshers_Quadrangle_2D "
                                           " on face #" << meshDS->ShapeToIndex( aFace )));
    }

    // 0.2.1 - number of points on the opposite edges must be the same
    if (aQuads[i]->side[0]->NbPoints() != aQuads[i]->side[2]->NbPoints() ||
        aQuads[i]->side[1]->NbPoints() != aQuads[i]->side[3]->NbPoints()
        /*aQuads[i]->side[0]->NbEdges() != 1 ||
        aQuads[i]->side[1]->NbEdges() != 1 ||
        aQuads[i]->side[2]->NbEdges() != 1 ||
        aQuads[i]->side[3]->NbEdges() != 1*/) {
      MESSAGE("different number of points on the opposite edges of face " << i);
      // Try to go into penta algorithm 'cause it has been improved.
      SMESH_ComputeErrorPtr err = ComputePentahedralMesh(aMesh, aShape);
      return ClearAndReturn( aQuads, error(err));
    }
  }

  // 1.  - identify faces and vertices of the "cube"
  // 1.1 - ancestor maps vertex->edges in the cube

//   TopTools_IndexedDataMapOfShapeListOfShape MS;
//   TopExp::MapShapesAndAncestors(aShape, TopAbs_VERTEX, TopAbs_EDGE, MS);

  // 1.2 - first face is choosen as face Y=0 of the unit cube

  const TopoDS_Shape & aFace = meshFaces[0]->GetSubShape();
  //const TopoDS_Face & F = TopoDS::Face(aFace);

  // 1.3 - identify the 4 vertices of the face Y=0: V000, V100, V101, V001

  aCube.V000 = aQuads[0]->side[0]->FirstVertex(); // will be (0,0,0) on the unit cube
  aCube.V100 = aQuads[0]->side[0]->LastVertex();  // will be (1,0,0) on the unit cube
  aCube.V001 = aQuads[0]->side[2]->FirstVertex(); // will be (0,0,1) on the unit cube
  aCube.V101 = aQuads[0]->side[2]->LastVertex();  // will be (1,0,1) on the unit cube

  TopTools_IndexedMapOfShape MV0;
  TopExp::MapShapes(aFace, TopAbs_VERTEX, MV0);

  aCube.V010 = OppositeVertex( aCube.V000, MV0, aQuads);
  aCube.V110 = OppositeVertex( aCube.V100, MV0, aQuads);
  aCube.V011 = OppositeVertex( aCube.V001, MV0, aQuads);
  aCube.V111 = OppositeVertex( aCube.V101, MV0, aQuads);

  // 1.6 - find remaining faces given 4 vertices

  int _indY0 = 0;
  int _indY1 = GetFaceIndex(aMesh, aShape, meshFaces,
                            aCube.V010, aCube.V011, aCube.V110, aCube.V111);
  int _indZ0 = GetFaceIndex(aMesh, aShape, meshFaces,
                            aCube.V000, aCube.V010, aCube.V100, aCube.V110);
  int _indZ1 = GetFaceIndex(aMesh, aShape, meshFaces,
                            aCube.V001, aCube.V011, aCube.V101, aCube.V111);
  int _indX0 = GetFaceIndex(aMesh, aShape, meshFaces,
                            aCube.V000, aCube.V001, aCube.V010, aCube.V011);
  int _indX1 = GetFaceIndex(aMesh, aShape, meshFaces,
                            aCube.V100, aCube.V101, aCube.V110, aCube.V111);

  // IPAL21120: SIGSEGV on Meshing attached Compound with Automatic Hexadralization
  if ( _indY1 < 1 || _indZ0 < 1 || _indZ1 < 1 || _indX0 < 1 || _indX1 < 1 )
    return error(COMPERR_BAD_SHAPE);

  aCube.quad_Y0 = aQuads[_indY0];
  aCube.quad_Y1 = aQuads[_indY1];
  aCube.quad_Z0 = aQuads[_indZ0];
  aCube.quad_Z1 = aQuads[_indZ1];
  aCube.quad_X0 = aQuads[_indX0];
  aCube.quad_X1 = aQuads[_indX1];

  // 1.7 - get convertion coefs from face 2D normalized to 3D normalized

  Conv2DStruct cx0;                     // for face X=0
  Conv2DStruct cx1;                     // for face X=1
  Conv2DStruct cy0;
  Conv2DStruct cy1;
  Conv2DStruct cz0;
  Conv2DStruct cz1;

  GetConv2DCoefs(*aCube.quad_X0, meshFaces[_indX0]->GetSubShape(),
                 aCube.V000, aCube.V010, aCube.V011, aCube.V001, cx0);
  GetConv2DCoefs(*aCube.quad_X1, meshFaces[_indX1]->GetSubShape(),
                 aCube.V100, aCube.V110, aCube.V111, aCube.V101, cx1);
  GetConv2DCoefs(*aCube.quad_Y0, meshFaces[_indY0]->GetSubShape(),
                 aCube.V000, aCube.V100, aCube.V101, aCube.V001, cy0);
  GetConv2DCoefs(*aCube.quad_Y1, meshFaces[_indY1]->GetSubShape(),
                 aCube.V010, aCube.V110, aCube.V111, aCube.V011, cy1);
  GetConv2DCoefs(*aCube.quad_Z0, meshFaces[_indZ0]->GetSubShape(),
                 aCube.V000, aCube.V100, aCube.V110, aCube.V010, cz0);
  GetConv2DCoefs(*aCube.quad_Z1, meshFaces[_indZ1]->GetSubShape(),
                 aCube.V001, aCube.V101, aCube.V111, aCube.V011, cz1);

  // 1.8 - create a 3D structure for normalized values
  
  int nbx = aCube.quad_Z0->side[0]->NbPoints();
  if (cz0.a1 == 0.) nbx = aCube.quad_Z0->side[1]->NbPoints();
 
  int nby = aCube.quad_X0->side[0]->NbPoints();
  if (cx0.a1 == 0.) nby = aCube.quad_X0->side[1]->NbPoints();
 
  int nbz = aCube.quad_Y0->side[0]->NbPoints();
  if (cy0.a1 != 0.) nbz = aCube.quad_Y0->side[1]->NbPoints();

  int i1, j1, nbxyz = nbx * nby * nbz;
  Point3DStruct *np = new Point3DStruct[nbxyz];

  // 1.9 - store node indexes of faces

  {
    const TopoDS_Face & F = TopoDS::Face(meshFaces[_indX0]->GetSubShape());

    faceQuadStruct *quad = aCube.quad_X0;
    int i = 0;                          // j = x/face , k = y/face
    int nbdown = quad->side[0]->NbPoints();
    int nbright = quad->side[1]->NbPoints();

    SMDS_NodeIteratorPtr itf= aMesh.GetSubMesh(F)->GetSubMeshDS()->GetNodes();
                        
    while(itf->more()) {
      const SMDS_MeshNode * node = itf->next();
      if(aTool.IsMedium(node))
        continue;
      if ( !findIJ( node, quad, i1, j1 ))
        return ClearAndReturn( aQuads, false );
      int ij1 = j1 * nbdown + i1;
      quad->uv_grid[ij1].node = node;
    }

    for (int i1 = 0; i1 < nbdown; i1++)
      for (int j1 = 0; j1 < nbright; j1++) {
        int ij1 = j1 * nbdown + i1;
        int j = cx0.ia * i1 + cx0.ib * j1 + cx0.ic;     // j = x/face
        int k = cx0.ja * i1 + cx0.jb * j1 + cx0.jc;     // k = y/face
        int ijk = k * nbx * nby + j * nbx + i;
        //MESSAGE(" "<<ij1<<" "<<i<<" "<<j<<" "<<ijk);
        np[ijk].node = quad->uv_grid[ij1].node;
        //SCRUTE(np[ijk].nodeId);
      }
  }

  {
    const TopoDS_Face & F = TopoDS::Face(meshFaces[_indX1]->GetSubShape());

    SMDS_NodeIteratorPtr itf= aMesh.GetSubMesh(F)->GetSubMeshDS()->GetNodes();

    faceQuadStruct *quad = aCube.quad_X1;
    int i = nbx - 1;            // j = x/face , k = y/face
    int nbdown = quad->side[0]->NbPoints();
    int nbright = quad->side[1]->NbPoints();

    while(itf->more()) {
      const SMDS_MeshNode * node = itf->next();
      if(aTool.IsMedium(node))
        continue;
      if ( !findIJ( node, quad, i1, j1 ))
        return ClearAndReturn( aQuads, false );
      int ij1 = j1 * nbdown + i1;
      quad->uv_grid[ij1].node = node;
    }

    for (int i1 = 0; i1 < nbdown; i1++)
      for (int j1 = 0; j1 < nbright; j1++) {
        int ij1 = j1 * nbdown + i1;
        int j = cx1.ia * i1 + cx1.ib * j1 + cx1.ic;     // j = x/face
        int k = cx1.ja * i1 + cx1.jb * j1 + cx1.jc;     // k = y/face
        int ijk = k * nbx * nby + j * nbx + i;
        //MESSAGE(" "<<ij1<<" "<<i<<" "<<j<<" "<<ijk);
        np[ijk].node = quad->uv_grid[ij1].node;
        //SCRUTE(np[ijk].nodeId);
      }
  }

  {
    const TopoDS_Face & F = TopoDS::Face(meshFaces[_indY0]->GetSubShape());

    SMDS_NodeIteratorPtr itf= aMesh.GetSubMesh(F)->GetSubMeshDS()->GetNodes();

    faceQuadStruct *quad = aCube.quad_Y0;
    int j = 0;                          // i = x/face , k = y/face
    int nbdown = quad->side[0]->NbPoints();
    int nbright = quad->side[1]->NbPoints();

    while(itf->more()) {
      const SMDS_MeshNode * node = itf->next();
      if(aTool.IsMedium(node))
        continue;
      if ( !findIJ( node, quad, i1, j1 ))
        return ClearAndReturn( aQuads, false );
      int ij1 = j1 * nbdown + i1;
      quad->uv_grid[ij1].node = node;
    }

    for (int i1 = 0; i1 < nbdown; i1++)
      for (int j1 = 0; j1 < nbright; j1++) {
        int ij1 = j1 * nbdown + i1;
        int i = cy0.ia * i1 + cy0.ib * j1 + cy0.ic;     // i = x/face
        int k = cy0.ja * i1 + cy0.jb * j1 + cy0.jc;     // k = y/face
        int ijk = k * nbx * nby + j * nbx + i;
        //MESSAGE(" "<<ij1<<" "<<i<<" "<<j<<" "<<ijk);
        np[ijk].node = quad->uv_grid[ij1].node;
        //SCRUTE(np[ijk].nodeId);
      }
  }

  {
    const TopoDS_Face & F = TopoDS::Face(meshFaces[_indY1]->GetSubShape());

    SMDS_NodeIteratorPtr itf= aMesh.GetSubMesh(F)->GetSubMeshDS()->GetNodes();

    faceQuadStruct *quad = aCube.quad_Y1;
    int j = nby - 1;            // i = x/face , k = y/face
    int nbdown = quad->side[0]->NbPoints();
    int nbright = quad->side[1]->NbPoints();

    while(itf->more()) {
      const SMDS_MeshNode * node = itf->next();
      if(aTool.IsMedium(node))
        continue;
      if ( !findIJ( node, quad, i1, j1 ))
        return ClearAndReturn( aQuads, false );
      int ij1 = j1 * nbdown + i1;
      quad->uv_grid[ij1].node = node;
    }

    for (int i1 = 0; i1 < nbdown; i1++)
      for (int j1 = 0; j1 < nbright; j1++) {
        int ij1 = j1 * nbdown + i1;
        int i = cy1.ia * i1 + cy1.ib * j1 + cy1.ic;     // i = x/face
        int k = cy1.ja * i1 + cy1.jb * j1 + cy1.jc;     // k = y/face
        int ijk = k * nbx * nby + j * nbx + i;
        //MESSAGE(" "<<ij1<<" "<<i<<" "<<j<<" "<<ijk);
        np[ijk].node = quad->uv_grid[ij1].node;
        //SCRUTE(np[ijk].nodeId);
      }
  }

  {
    const TopoDS_Face & F = TopoDS::Face(meshFaces[_indZ0]->GetSubShape());

    SMDS_NodeIteratorPtr itf= aMesh.GetSubMesh(F)->GetSubMeshDS()->GetNodes();

    faceQuadStruct *quad = aCube.quad_Z0;
    int k = 0;                          // i = x/face , j = y/face
    int nbdown = quad->side[0]->NbPoints();
    int nbright = quad->side[1]->NbPoints();

    while(itf->more()) {
      const SMDS_MeshNode * node = itf->next();
      if(aTool.IsMedium(node))
        continue;
      if ( !findIJ( node, quad, i1, j1 ))
        return ClearAndReturn( aQuads, false );
      int ij1 = j1 * nbdown + i1;
      quad->uv_grid[ij1].node = node;
    }

    for (int i1 = 0; i1 < nbdown; i1++)
      for (int j1 = 0; j1 < nbright; j1++) {
        int ij1 = j1 * nbdown + i1;
        int i = cz0.ia * i1 + cz0.ib * j1 + cz0.ic;     // i = x/face
        int j = cz0.ja * i1 + cz0.jb * j1 + cz0.jc;     // j = y/face
        int ijk = k * nbx * nby + j * nbx + i;
        //MESSAGE(" "<<ij1<<" "<<i<<" "<<j<<" "<<ijk);
        np[ijk].node = quad->uv_grid[ij1].node;
        //SCRUTE(np[ijk].nodeId);
      }
  }

  {
    const TopoDS_Face & F = TopoDS::Face(meshFaces[_indZ1]->GetSubShape());

    SMDS_NodeIteratorPtr itf= aMesh.GetSubMesh(F)->GetSubMeshDS()->GetNodes();

    faceQuadStruct *quad = aCube.quad_Z1;
    int k = nbz - 1;            // i = x/face , j = y/face
    int nbdown = quad->side[0]->NbPoints();
    int nbright = quad->side[1]->NbPoints();
    
    while(itf->more()) {
      const SMDS_MeshNode * node = itf->next();
      if(aTool.IsMedium(node))
        continue;
      if ( !findIJ( node, quad, i1, j1 ))
        return ClearAndReturn( aQuads, false );
      int ij1 = j1 * nbdown + i1;
      quad->uv_grid[ij1].node = node;
    }

    for (int i1 = 0; i1 < nbdown; i1++)
      for (int j1 = 0; j1 < nbright; j1++) {
        int ij1 = j1 * nbdown + i1;
        int i = cz1.ia * i1 + cz1.ib * j1 + cz1.ic;     // i = x/face
        int j = cz1.ja * i1 + cz1.jb * j1 + cz1.jc;     // j = y/face
        int ijk = k * nbx * nby + j * nbx + i;
        //MESSAGE(" "<<ij1<<" "<<i<<" "<<j<<" "<<ijk);
        np[ijk].node = quad->uv_grid[ij1].node;
        //SCRUTE(np[ijk].nodeId);
      }
  }

  // 2.0 - for each node of the cube:
  //       - get the 8 points 3D = 8 vertices of the cube
  //       - get the 12 points 3D on the 12 edges of the cube
  //       - get the 6 points 3D on the 6 faces with their ID
  //       - compute the point 3D
  //       - store the point 3D in SMESHDS, store its ID in 3D structure

  int shapeID = meshDS->ShapeToIndex( aShape );

  Pt3 p000, p001, p010, p011, p100, p101, p110, p111;
  Pt3 px00, px01, px10, px11;
  Pt3 p0y0, p0y1, p1y0, p1y1;
  Pt3 p00z, p01z, p10z, p11z;
  Pt3 pxy0, pxy1, px0z, px1z, p0yz, p1yz;

  GetPoint(p000, 0, 0, 0, nbx, nby, nbz, np, meshDS);
  GetPoint(p001, 0, 0, nbz - 1, nbx, nby, nbz, np, meshDS);
  GetPoint(p010, 0, nby - 1, 0, nbx, nby, nbz, np, meshDS);
  GetPoint(p011, 0, nby - 1, nbz - 1, nbx, nby, nbz, np, meshDS);
  GetPoint(p100, nbx - 1, 0, 0, nbx, nby, nbz, np, meshDS);
  GetPoint(p101, nbx - 1, 0, nbz - 1, nbx, nby, nbz, np, meshDS);
  GetPoint(p110, nbx - 1, nby - 1, 0, nbx, nby, nbz, np, meshDS);
  GetPoint(p111, nbx - 1, nby - 1, nbz - 1, nbx, nby, nbz, np, meshDS);

  for (int i = 1; i < nbx - 1; i++) {
    for (int j = 1; j < nby - 1; j++) {
      for (int k = 1; k < nbz - 1; k++) {
        // *** seulement maillage regulier
        // 12 points on edges
        GetPoint(px00, i, 0, 0, nbx, nby, nbz, np, meshDS);
        GetPoint(px01, i, 0, nbz - 1, nbx, nby, nbz, np, meshDS);
        GetPoint(px10, i, nby - 1, 0, nbx, nby, nbz, np, meshDS);
        GetPoint(px11, i, nby - 1, nbz - 1, nbx, nby, nbz, np, meshDS);

        GetPoint(p0y0, 0, j, 0, nbx, nby, nbz, np, meshDS);
        GetPoint(p0y1, 0, j, nbz - 1, nbx, nby, nbz, np, meshDS);
        GetPoint(p1y0, nbx - 1, j, 0, nbx, nby, nbz, np, meshDS);
        GetPoint(p1y1, nbx - 1, j, nbz - 1, nbx, nby, nbz, np, meshDS);

        GetPoint(p00z, 0, 0, k, nbx, nby, nbz, np, meshDS);
        GetPoint(p01z, 0, nby - 1, k, nbx, nby, nbz, np, meshDS);
        GetPoint(p10z, nbx - 1, 0, k, nbx, nby, nbz, np, meshDS);
        GetPoint(p11z, nbx - 1, nby - 1, k, nbx, nby, nbz, np, meshDS);

        // 12 points on faces
        GetPoint(pxy0, i, j, 0, nbx, nby, nbz, np, meshDS);
        GetPoint(pxy1, i, j, nbz - 1, nbx, nby, nbz, np, meshDS);
        GetPoint(px0z, i, 0, k, nbx, nby, nbz, np, meshDS);
        GetPoint(px1z, i, nby - 1, k, nbx, nby, nbz, np, meshDS);
        GetPoint(p0yz, 0, j, k, nbx, nby, nbz, np, meshDS);
        GetPoint(p1yz, nbx - 1, j, k, nbx, nby, nbz, np, meshDS);

        int ijk = k * nbx * nby + j * nbx + i;
        double x = double (i) / double (nbx - 1);       // *** seulement
        double y = double (j) / double (nby - 1);       // *** maillage
        double z = double (k) / double (nbz - 1);       // *** regulier

        Pt3 X;
        for (int i = 0; i < 3; i++) {
          X[i] = (1 - x) * p0yz[i] + x * p1yz[i]
                 + (1 - y) * px0z[i] + y * px1z[i]
                 + (1 - z) * pxy0[i] + z * pxy1[i]
                 - (1 - x) * ((1 - y) * p00z[i] + y * p01z[i])
                 - x * ((1 - y) * p10z[i] + y * p11z[i])
                 - (1 - y) * ((1 - z) * px00[i] + z * px01[i])
                 - y * ((1 - z) * px10[i] + z * px11[i])
                 - (1 - z) * ((1 - x) * p0y0[i] + x * p1y0[i])
                 - z * ((1 - x) * p0y1[i] + x * p1y1[i])
                 + (1 - x) * ((1 - y) * ((1 - z) * p000[i] + z * p001[i])
                 + y * ((1 - z) * p010[i] + z * p011[i]))
                 + x * ((1 - y) * ((1 - z) * p100[i] + z * p101[i])
                 + y * ((1 - z) * p110[i] + z * p111[i]));
        }

        SMDS_MeshNode * node = meshDS->AddNode(X[0], X[1], X[2]);
        np[ijk].node = node;
        meshDS->SetNodeInVolume(node, shapeID);
      }
    }
  }

  // find orientation of furute volumes according to MED convention
  vector< bool > forward( nbx * nby );
  SMDS_VolumeTool vTool;
  for (int i = 0; i < nbx - 1; i++) {
    for (int j = 0; j < nby - 1; j++) {
      int n1 = j * nbx + i;
      int n2 = j * nbx + i + 1;
      int n3 = (j + 1) * nbx + i + 1;
      int n4 = (j + 1) * nbx + i;
      int n5 = nbx * nby + j * nbx + i;
      int n6 = nbx * nby + j * nbx + i + 1;
      int n7 = nbx * nby + (j + 1) * nbx + i + 1;
      int n8 = nbx * nby + (j + 1) * nbx + i;

      SMDS_VolumeOfNodes tmpVol (np[n1].node,np[n2].node,np[n3].node,np[n4].node,
                                 np[n5].node,np[n6].node,np[n7].node,np[n8].node);
      vTool.Set( &tmpVol );
      forward[ n1 ] = vTool.IsForward();
    }
  }

  //2.1 - for each node of the cube (less 3 *1 Faces):
  //      - store hexahedron in SMESHDS
  MESSAGE("Storing hexahedron into the DS");
  for (int i = 0; i < nbx - 1; i++) {
    for (int j = 0; j < nby - 1; j++) {
      bool isForw = forward.at( j * nbx + i );
      for (int k = 0; k < nbz - 1; k++) {
        int n1 = k * nbx * nby + j * nbx + i;
        int n2 = k * nbx * nby + j * nbx + i + 1;
        int n3 = k * nbx * nby + (j + 1) * nbx + i + 1;
        int n4 = k * nbx * nby + (j + 1) * nbx + i;
        int n5 = (k + 1) * nbx * nby + j * nbx + i;
        int n6 = (k + 1) * nbx * nby + j * nbx + i + 1;
        int n7 = (k + 1) * nbx * nby + (j + 1) * nbx + i + 1;
        int n8 = (k + 1) * nbx * nby + (j + 1) * nbx + i;

        SMDS_MeshVolume * elt;
        if ( isForw ) {
          elt = aTool.AddVolume(np[n1].node, np[n2].node,
                                np[n3].node, np[n4].node,
                                np[n5].node, np[n6].node,
                                np[n7].node, np[n8].node);
        }
        else {
          elt = aTool.AddVolume(np[n1].node, np[n4].node,
                                np[n3].node, np[n2].node,
                                np[n5].node, np[n8].node,
                                np[n7].node, np[n6].node);
        }
        
        meshDS->SetMeshElementOnShape(elt, shapeID);
      }
    }
  }
  if ( np ) delete [] np;
  return ClearAndReturn( aQuads, true );
}