diff --git a/hurricane/src/hurricane/Cell.cpp b/hurricane/src/hurricane/Cell.cpp
index 970c2512..076091a7 100644
--- a/hurricane/src/hurricane/Cell.cpp
+++ b/hurricane/src/hurricane/Cell.cpp
@@ -955,6 +955,50 @@ void Cell::createRoutingPadRings(uint64_t flags)
 }
 
 
+void Cell::destroyPhysical()
+// *************************
+{
+  cdebug_log(18,0) << "Cell::destroyPhysical()" << endl;
+
+  UpdateSession::open();
+  for ( Net* net : getNets() ) {
+    vector<Component*> removeds;
+    for ( Component* component : net->getComponents() ) {
+      if (dynamic_cast<RoutingPad*>(component)) removeds.push_back( component );
+    }
+    for ( Component* component : removeds ) component->destroy();
+  }
+
+  vector<DeepNet*> deepNets;
+  for ( Net* net : getNets() ) {
+    DeepNet* deepNet = dynamic_cast<DeepNet*>( net );
+    if (deepNet) deepNets.push_back( deepNet );
+  }
+  for ( DeepNet* deepNet : deepNets ) {
+    cerr << "Removing DeepNet:" << deepNet << endl;
+    deepNet->destroy();
+  }
+
+  for ( Net* net : getNets() ) {
+    vector<Component*> removeds;
+    for ( Component* component : net->getComponents() ) {
+      if (dynamic_cast<Plug   *>(component)) continue;
+      if (dynamic_cast<Contact*>(component)) removeds.push_back( component );
+    }
+    for ( Component* component : removeds ) component->destroy();
+  }
+
+  for ( Net* net : getNets() ) {
+    vector<Component*> removeds;
+    for ( Component* component : net->getComponents() ) {
+      if (dynamic_cast<Plug*>(component)) continue;
+      removeds.push_back( component );
+    }
+    for ( Component* component : removeds ) component->destroy();
+  }
+  UpdateSession::close();
+}
+
 Cell* Cell::getCloneMaster() const
 // *******************************
 {
diff --git a/hurricane/src/hurricane/CellCollections.cpp b/hurricane/src/hurricane/CellCollections.cpp
index d503ccb3..9fc43fdb 100644
--- a/hurricane/src/hurricane/CellCollections.cpp
+++ b/hurricane/src/hurricane/CellCollections.cpp
@@ -1722,11 +1722,13 @@ class Cell_SubCells : public Collection<Cell*> {
 // Cell further definition
 // ****************************************************************************************************
 
-Instances Cell::getInstancesUnder(const Box& area) const
-// *****************************************************
+Instances Cell::getInstancesUnder(const Box& area, DbU::Unit threshold) const
+// **************************************************************************
 {
-    // return _quadTree.getGosUnder(area).getSubSet<Instance*>();
-    return SubTypeCollection<Go*, Instance*>(_quadTree->getGosUnder(area));
+// return _quadTree.getGosUnder(area).getSubSet<Instance*>();
+//cerr << "Cell::getInstancesUnder(): t:" << DbU::getValueString(threshold)
+//     << " " << this << endl;
+  return SubTypeCollection<Go*, Instance*>(_quadTree->getGosUnder(area,threshold));
 }
 
 Instances Cell::getSlaveInstances() const
diff --git a/hurricane/src/hurricane/QuadTree.cpp b/hurricane/src/hurricane/QuadTree.cpp
index 91deea56..a0dd2991 100644
--- a/hurricane/src/hurricane/QuadTree.cpp
+++ b/hurricane/src/hurricane/QuadTree.cpp
@@ -122,12 +122,13 @@ class QuadTree_GosUnder : public Collection<Go*> {
 
         private: const QuadTree* _quadTree;
         private: Box _area;
+        private: DbU::Unit _threshold;
         private: QuadTree* _currentQuadTree;
         private: GoLocator _goLocator;
       //private: static size_t _allocateds;
 
         public: Locator();
-        public: Locator(const QuadTree* quadTree, const Box& area);
+        public: Locator(const QuadTree* quadTree, const Box& area, DbU::Unit threshold);
         public: Locator(const Locator& locator);
       //public: ~Locator() { _allocateds--; }
 
@@ -150,12 +151,13 @@ class QuadTree_GosUnder : public Collection<Go*> {
 
     private: const QuadTree* _quadTree;
     private: Box _area;
+    private: DbU::Unit _threshold;
 
 // Constructors
 // ************
 
     public: QuadTree_GosUnder();
-    public: QuadTree_GosUnder(const QuadTree* quadTree, const Box& area);
+    public: QuadTree_GosUnder(const QuadTree* quadTree, const Box& area, DbU::Unit threshold);
     public: QuadTree_GosUnder(const QuadTree_GosUnder& gos);
 
 // Operators
@@ -251,10 +253,10 @@ Gos QuadTree::getGos() const
     return QuadTree_Gos(this);
 }
 
-Gos QuadTree::getGosUnder(const Box& area) const
-// *********************************************
+Gos QuadTree::getGosUnder(const Box& area, DbU::Unit threshold) const
+// ******************************************************************
 {
-    return QuadTree_GosUnder(this, area);
+  return QuadTree_GosUnder(this, area, threshold);
 }
 
 void QuadTree::insert(Go* go)
@@ -687,25 +689,28 @@ string QuadTree_Gos::Locator::_getString() const
 
 QuadTree_GosUnder::QuadTree_GosUnder()
 // ***********************************
-:     Inherit(),
+:   Inherit(),
     _quadTree(NULL),
-    _area()
+    _area(),
+    _threshold(0)
 {
 }
 
-QuadTree_GosUnder::QuadTree_GosUnder(const QuadTree* quadTree, const Box& area)
-// ****************************************************************************
-:     Inherit(),
+QuadTree_GosUnder::QuadTree_GosUnder(const QuadTree* quadTree, const Box& area, DbU::Unit threshold)
+// *************************************************************************************************
+:   Inherit(),
     _quadTree(quadTree),
-    _area(area)
+    _area(area),
+    _threshold(threshold)
 {
 }
 
 QuadTree_GosUnder::QuadTree_GosUnder(const QuadTree_GosUnder& gos)
 // ***************************************************************
-:     Inherit(),
+:   Inherit(),
     _quadTree(gos._quadTree),
-    _area(gos._area)
+    _area(gos._area),
+    _threshold(gos._threshold)
 {
 }
 
@@ -714,6 +719,7 @@ QuadTree_GosUnder& QuadTree_GosUnder::operator=(const QuadTree_GosUnder& gos)
 {
     _quadTree = gos._quadTree;
     _area = gos._area;
+    _threshold = gos._threshold;
     return *this;
 }
 
@@ -726,7 +732,7 @@ Collection<Go*>* QuadTree_GosUnder::getClone() const
 Locator<Go*>* QuadTree_GosUnder::getLocator() const
 // ************************************************
 {
-    return new Locator(_quadTree, _area);
+  return new Locator(_quadTree, _area, _threshold);
 }
 
 string QuadTree_GosUnder::_getString() const
@@ -736,6 +742,7 @@ string QuadTree_GosUnder::_getString() const
     if (_quadTree) {
         s += " " + getString(_quadTree);
         s += " " + getString(_area);
+        s += " t:" + DbU::getValueString(_threshold);
     }
     s += ">";
     return s;
@@ -752,23 +759,38 @@ QuadTree_GosUnder::Locator::Locator()
 :    Inherit(),
     _quadTree(NULL),
     _area(),
+    _threshold(0),
     _currentQuadTree(NULL),
     _goLocator()
 {
   //_allocateds++;
 }
 
-QuadTree_GosUnder::Locator::Locator(const QuadTree* quadTree, const Box& area)
-// ***************************************************************************
+QuadTree_GosUnder::Locator::Locator(const QuadTree* quadTree, const Box& area, DbU::Unit threshold)
+// ************************************************************************************************
 :    Inherit(),
     _quadTree(quadTree),
     _area(area),
+    _threshold(threshold),
     _currentQuadTree(NULL),
     _goLocator()
 {
     //_allocateds++;
-    if (_quadTree && !_area.isEmpty()) {
+    if (_quadTree and not _area.isEmpty()) {
         _currentQuadTree = _quadTree->_getFirstQuadTree(_area);
+        while ( true ) {
+          if (not _currentQuadTree) break;
+          if (   (_threshold <= 0)
+             or (   (_currentQuadTree->getBoundingBox().getWidth () > _threshold)
+                and (_currentQuadTree->getBoundingBox().getHeight() > _threshold)) )
+            break;
+          // cerr << "Pruning QuadTree:" << _currentQuadTree
+          //      << " _threshold:" << DbU::getValueString(_threshold)
+          //      << "(" << _threshold << ")" << endl;
+          _currentQuadTree = _currentQuadTree->_getNextQuadTree(_area);
+        }
+
+      //_currentQuadTree = _quadTree->_getFirstQuadTree(_area);
         if (_currentQuadTree) {
             _goLocator = _currentQuadTree->_getGoSet().getElements().getLocator();
             if (!getElement()->getBoundingBox().intersect(_area)) progress();
@@ -781,6 +803,7 @@ QuadTree_GosUnder::Locator::Locator(const Locator& locator)
 :    Inherit(),
     _quadTree(locator._quadTree),
     _area(locator._area),
+    _threshold(locator._threshold),
     _currentQuadTree(locator._currentQuadTree),
     _goLocator(locator._goLocator)
 {
@@ -792,6 +815,7 @@ QuadTree_GosUnder::Locator& QuadTree_GosUnder::Locator::operator=(const Locator&
 {
     _quadTree = locator._quadTree;
     _area = locator._area;
+    _threshold = locator._threshold;
     _currentQuadTree = locator._currentQuadTree;
     _goLocator = locator._goLocator;
     return *this;
@@ -818,16 +842,27 @@ bool QuadTree_GosUnder::Locator::isValid() const
 void QuadTree_GosUnder::Locator::progress()
 // ****************************************
 {
-    if (isValid()) {
-        do {
-            _goLocator.progress();
-            if (!_goLocator.isValid()) {
-                _currentQuadTree = _currentQuadTree->_getNextQuadTree(_area);
-                if (_currentQuadTree)
-                    _goLocator = _currentQuadTree->_getGoSet().getElements().getLocator();
-            }
-        } while (isValid() && !getElement()->getBoundingBox().intersect(_area));
-    }
+  if (isValid()) {
+    do {
+      _goLocator.progress();
+      if (not _goLocator.isValid()) {
+        while ( true ) {
+          _currentQuadTree = _currentQuadTree->_getNextQuadTree(_area);
+          if (not _currentQuadTree) break;
+          if (  (_threshold <= 0)
+             or (   (_currentQuadTree->getBoundingBox().getWidth () > _threshold)
+                and (_currentQuadTree->getBoundingBox().getHeight() > _threshold)) )
+            break;
+          // cerr << "Pruning QuadTree:" << _currentQuadTree
+          //      << " _threshold:" << DbU::getValueString(_threshold)
+          //      << "(" << _threshold << ")" << endl;
+        }
+
+        if (_currentQuadTree)
+          _goLocator = _currentQuadTree->_getGoSet().getElements().getLocator();
+      }
+    } while (isValid() and not getElement()->getBoundingBox().intersect(_area));
+  }
 }
 
 string QuadTree_GosUnder::Locator::_getString() const
diff --git a/hurricane/src/hurricane/Query.cpp b/hurricane/src/hurricane/Query.cpp
index 4ea7f0e2..015aed9c 100644
--- a/hurricane/src/hurricane/Query.cpp
+++ b/hurricane/src/hurricane/Query.cpp
@@ -47,6 +47,7 @@ namespace Hurricane {
   //, _tab               ("  ")
     , _topCell           (NULL)
     , _topArea           ()
+    , _threshold         (0)
     , _topTransformation ()
     , _startLevel        (0)
     , _stopLevel         (std::numeric_limits<unsigned int>::max())
@@ -84,6 +85,7 @@ namespace Hurricane {
                         , const BasicLayer*     basicLayer
                         , ExtensionSlice::Mask  mask
                         , Mask                  filter
+                        , DbU::Unit             threshold
                         )
   {
     _basicLayer    = basicLayer;
@@ -93,62 +95,72 @@ namespace Hurricane {
     _stack.setTopCell           ( cell );
     _stack.setTopArea           ( area );
     _stack.setTopTransformation ( transformation );
+    _stack.setThreshold         ( threshold );
   }
 
 
   void  Query::doQuery ()
   {
-    if ( _stack.getTopArea().isEmpty() or not _stack.getTopCell() ) return;
+    if (_stack.getTopArea().isEmpty() or not _stack.getTopCell()) return;
     
-  //cerr << "Query::doQuery() - " << _stack.getTopCell() << " " << _stack.getTopArea() << " " << _basicLayer << endl;
+    // cerr << "Query::doQuery() - " << _stack.getTopCell()
+    //      << " " << _stack.getTopArea()
+    //      << " " << _basicLayer
+    //      << " threshold:" << DbU::getValueString(_stack.getThreshold())
+    //      << endl;
 
-    _stack.init ();
+    _stack.init();
 
-    while ( !_stack.empty() ) {
+    while ( not _stack.empty() ) {
     // Process the Components of the current instance.
-      if ( hasGoCallback() and _basicLayer and (_filter.isSet(DoComponents)) ) {
-      //if ( getInstance() )
-      //  cerr << getTab() << getInstance() << " " << getTransformation() << endl;
-      //else
-      //  cerr << "  TopCell: " << getMasterCell() << " " << getTransformation() << endl;
-
-        if ( not getMasterCell()->isTerminal() or (_filter.isSet(DoTerminalCells)) ) {
-          forEach ( Slice*, islice, getMasterCell()->getSlices() ) {
-            if ( not (*islice)->getLayer()->contains(getBasicLayer()) ) continue;
-            if ( not (*islice)->getBoundingBox().intersect(getArea()) ) continue;
-
-            forEach ( Go*, igo, (*islice)->getGosUnder(_stack.getArea()) )
-              goCallback ( *igo );
-          }
-        }
-      }
-
-      if ( (not getMasterCell()->isTerminal() or (_filter.isSet(DoTerminalCells)))
-         and _filter.isSet(DoMarkers) ) {
-        forEach ( Marker*, marker, getMasterCell()->getMarkersUnder(_stack.getArea()) )
-          markerCallback ( *marker );
-      }
-
-      if ( not getMasterCell()->isTerminal() and (_filter.isSet(DoRubbers)) ) {
-        forEach ( Rubber*, rubber, getMasterCell()->getRubbersUnder(_stack.getArea()) )
-          rubberCallback ( *rubber );
-      }
-
-      if ( hasExtensionGoCallback() and (_filter.isSet(DoExtensionGos)) ) {
-        if ( (not getMasterCell()->isTerminal()) or (_filter.isSet(DoTerminalCells)) ) {
-          forEach ( ExtensionSlice*, islice, getMasterCell()->getExtensionSlices() ) {
-            if ( not ( (*islice)->getMask() & _extensionMask ) ) continue;
-            if ( not (*islice)->getBoundingBox().intersect(getArea()) ) continue;
-
-            for ( Go* go : (*islice)->getGosUnder(_stack.getArea()) ) {
-              extensionGoCallback ( go );
+      Box ab = getMasterCell()->getAbutmentBox();
+      if (  (_stack.getThreshold() <= 0)
+         or (ab.getWidth () > _stack.getThreshold())
+         or (ab.getHeight() > _stack.getThreshold()) ) {
+        if (hasGoCallback() and _basicLayer and (_filter.isSet(DoComponents))) {
+        //if ( getInstance() )
+        //  cerr << getTab() << getInstance() << " " << getTransformation() << endl;
+        //else
+        //  cerr << "  TopCell: " << getMasterCell() << " " << getTransformation() << endl;
+        
+          if (not getMasterCell()->isTerminal() or (_filter.isSet(DoTerminalCells))) {
+            for ( Slice* slice : getMasterCell()->getSlices() ) {
+              if (not slice->getLayer()->contains(getBasicLayer())) continue;
+              if (not slice->getBoundingBox().intersect(getArea())) continue;
+        
+              for ( Go* go : slice->getGosUnder(_stack.getArea(),_stack.getThreshold()) )
+                goCallback( go );
+            }
+          }
+        }
+        
+        if ( (not getMasterCell()->isTerminal() or (_filter.isSet(DoTerminalCells)))
+           and _filter.isSet(DoMarkers) ) {
+          for ( Marker* marker : getMasterCell()->getMarkersUnder(_stack.getArea()) )
+            markerCallback( marker );
+        }
+        
+        if ( not getMasterCell()->isTerminal() and (_filter.isSet(DoRubbers)) ) {
+          for ( Rubber* rubber : getMasterCell()->getRubbersUnder(_stack.getArea()) )
+            rubberCallback( rubber );
+        }
+        
+        if ( hasExtensionGoCallback() and (_filter.isSet(DoExtensionGos)) ) {
+          if ( (not getMasterCell()->isTerminal()) or (_filter.isSet(DoTerminalCells)) ) {
+            for ( ExtensionSlice* slice : getMasterCell()->getExtensionSlices() ) {
+              if ( not ( slice->getMask() & _extensionMask ) ) continue;
+              if ( not slice->getBoundingBox().intersect(getArea()) ) continue;
+        
+              for ( Go* go : slice->getGosUnder(_stack.getArea(),_stack.getThreshold()) ) {
+                extensionGoCallback( go );
+              }
             }
           }
         }
-      }
 
-      if ( (_filter.isSet(DoMasterCells)) and hasMasterCellCallback() )
-        masterCellCallback ();
+        if ( (_filter.isSet(DoMasterCells)) and hasMasterCellCallback() )
+          masterCellCallback ();
+      }
 
       _stack.progress ();
     } // End of while.
diff --git a/hurricane/src/hurricane/Slice.cpp b/hurricane/src/hurricane/Slice.cpp
index f9056295..a8ff6bb5 100644
--- a/hurricane/src/hurricane/Slice.cpp
+++ b/hurricane/src/hurricane/Slice.cpp
@@ -64,11 +64,11 @@ Components Slice::getComponents() const
     return SubTypeCollection<Go*, Component*>(_quadTree.getGos());
 }
 
-Components Slice::getComponentsUnder(const Box& area) const
-// ********************************************************
+Components Slice::getComponentsUnder(const Box& area, DbU::Unit threshold) const
+// *****************************************************************************
 {
     // return _quadTree.getGosUnder(area).getSubSet<Component*>();
-    return SubTypeCollection<Go*, Component*>(_quadTree.getGosUnder(area));
+    return SubTypeCollection<Go*, Component*>(_quadTree.getGosUnder(area,threshold));
 }
 
 Markers Slice::getMarkers() const
diff --git a/hurricane/src/hurricane/hurricane/Cell.h b/hurricane/src/hurricane/hurricane/Cell.h
index 9b808f8f..4e3d9d2f 100644
--- a/hurricane/src/hurricane/hurricane/Cell.h
+++ b/hurricane/src/hurricane/hurricane/Cell.h
@@ -420,7 +420,7 @@ class Cell : public Entity {
     public: Instances getFixedInstances() const;
     public: Instances getUnplacedInstances() const;
     public: Instances getNotUnplacedInstances() const;
-    public: Instances getInstancesUnder(const Box& area) const;
+    public: Instances getInstancesUnder(const Box& area, DbU::Unit threshold=0) const;
     public: Instances getPlacedInstancesUnder(const Box& area) const;
     public: Instances getFixedInstancesUnder(const Box& area) const;
     public: Instances getUnplacedInstancesUnder(const Box& area) const;
@@ -518,8 +518,8 @@ class Cell : public Entity {
     public: void uniquify(unsigned int depth=std::numeric_limits<unsigned int>::max());
     public: void addObserver(BaseObserver*);
     public: void removeObserver(BaseObserver*);
-    public: void notify(unsigned flags);
-
+    public: void notify(unsigned flags);  
+    public: void destroyPhysical();
 };
 
 
diff --git a/hurricane/src/hurricane/hurricane/ExtensionSlice.h b/hurricane/src/hurricane/hurricane/ExtensionSlice.h
index 9fa48070..97c8089f 100644
--- a/hurricane/src/hurricane/hurricane/ExtensionSlice.h
+++ b/hurricane/src/hurricane/hurricane/ExtensionSlice.h
@@ -30,9 +30,7 @@
 // +-----------------------------------------------------------------+
 
 
-#ifndef  HURRICANE_EXTENSION_SLICE_H
-#define  HURRICANE_EXTENSION_SLICE_H
-
+#pragma  once
 #include "hurricane/Mask.h"
 #include "hurricane/Name.h"
 #include "hurricane/ExtensionSlices.h"
@@ -60,7 +58,7 @@ namespace Hurricane {
       inline  Mask                getMask        () const;
       inline  const Box&          getBoundingBox () const;
       inline  Gos                 getGos         () const;
-      inline  Gos                 getGosUnder    ( const Box& area ) const;
+      inline  Gos                 getGosUnder    ( const Box& area, DbU::Unit threshold=0 ) const;
       inline  QuadTree*           _getQuadTree   ();
     // Hurricane Managment.
               string              _getTypeName   () const;
@@ -93,12 +91,10 @@ namespace Hurricane {
   inline ExtensionSlice::Mask  ExtensionSlice::getMask        () const { return _mask; }
   inline const Box&            ExtensionSlice::getBoundingBox () const { return _quadTree.getBoundingBox(); }
   inline Gos                   ExtensionSlice::getGos         () const { return _quadTree.getGos(); }
-  inline Gos                   ExtensionSlice::getGosUnder    ( const Box& area ) const {return _quadTree.getGosUnder(area); }
+  inline Gos                   ExtensionSlice::getGosUnder    ( const Box& area, DbU::Unit threshold ) const {return _quadTree.getGosUnder(area,threshold); }
   inline QuadTree*             ExtensionSlice::_getQuadTree   () { return &_quadTree; }
 
 
 } // End of Hurricane namespace.
 
 INSPECTOR_P_SUPPORT(Hurricane::ExtensionSlice);
-
-# endif // HURRICANE_EXTENSION_SLICE_H
diff --git a/hurricane/src/hurricane/hurricane/QuadTree.h b/hurricane/src/hurricane/hurricane/QuadTree.h
index 621ccd38..322694ad 100644
--- a/hurricane/src/hurricane/hurricane/QuadTree.h
+++ b/hurricane/src/hurricane/hurricane/QuadTree.h
@@ -17,9 +17,7 @@
 // not, see <http://www.gnu.org/licenses/>.
 // ****************************************************************************************************
 
-#ifndef HURRICANE_QUAD_TREE
-#define HURRICANE_QUAD_TREE
-
+#pragma  once
 #include "hurricane/Box.h"
 #include "hurricane/Gos.h"
 #include "hurricane/IntrusiveSet.h"
@@ -88,7 +86,7 @@ class QuadTree {
   //public: static size_t getLocatorAllocateds ();
     public: const Box& getBoundingBox() const;
     public: Gos getGos() const;
-    public: Gos getGosUnder(const Box& area) const;
+    public: Gos getGosUnder(const Box& area, DbU::Unit threshold=0) const;
 
 // Predicates
 // **********
@@ -130,9 +128,6 @@ INSPECTOR_P_SUPPORT(Hurricane::QuadTree);
 INSPECTOR_P_SUPPORT(Hurricane::QuadTree::GoSet);
 
 
-#endif // HURRICANE_QUAD_TREE
-
-
 // ****************************************************************************************************
 // Copyright (c) BULL S.A. 2000-2018, All Rights Reserved
 // ****************************************************************************************************
diff --git a/hurricane/src/hurricane/hurricane/Query.h b/hurricane/src/hurricane/hurricane/Query.h
index 19563d25..d78de5dd 100644
--- a/hurricane/src/hurricane/hurricane/Query.h
+++ b/hurricane/src/hurricane/hurricane/Query.h
@@ -29,9 +29,7 @@
 // +-----------------------------------------------------------------+
 
 
-#ifndef  HURRICANE_QUERY_H
-#define  HURRICANE_QUERY_H
-
+#pragma  once
 #include <vector>
 #include "hurricane/Commons.h"
 #include "hurricane/Box.h"
@@ -118,6 +116,7 @@ namespace Hurricane {
       inline  Cell*                 getMasterCell        ();
       inline  Instance*             getInstance          ();
       inline  const Box&            getArea              () const;
+      inline  DbU::Unit             getThreshold         () const;
       inline  const Transformation& getTransformation    () const;
       inline  const Path&           getPath              () const;
     //inline  const Tabulation&     getTab               () const;
@@ -125,6 +124,7 @@ namespace Hurricane {
       inline  void                  setTopCell           ( Cell*                 cell );
       inline  void                  setTopArea           ( const Box&            area );
       inline  void                  setTopTransformation ( const Transformation& transformation );
+      inline  void                  setThreshold         ( DbU::Unit             threshold );
       inline  void                  setStartLevel        ( unsigned int          level );
       inline  void                  setStopLevel         ( unsigned int          level );
       inline  void                  init                 ();
@@ -140,6 +140,7 @@ namespace Hurricane {
     //        Tabulation            _tab;
               Cell*                 _topCell;
               Box                   _topArea;
+              DbU::Unit             _threshold;
               Transformation        _topTransformation;
               unsigned int          _startLevel;
               unsigned int          _stopLevel;
@@ -157,6 +158,7 @@ namespace Hurricane {
   inline  Cell*                 QueryStack::getTopCell           () { return _topCell; }
   inline  const Box&            QueryStack::getTopArea           () const { return _topArea; }
   inline  const Transformation& QueryStack::getTopTransformation () const { return _topTransformation; }
+  inline  DbU::Unit             QueryStack::getThreshold         () const { return _threshold; }
   inline  unsigned int          QueryStack::getStartLevel        () const { return _startLevel; }
   inline  unsigned int          QueryStack::getStopLevel         () const { return _stopLevel; }
   inline  const Box&            QueryStack::getArea              () const { return back()->_area; }
@@ -183,6 +185,7 @@ namespace Hurricane {
   inline  void  QueryStack::setTopCell           ( Cell*                 cell )           { _topCell = cell; }
   inline  void  QueryStack::setTopArea           ( const Box&            area )           { _topArea = area; }
   inline  void  QueryStack::setTopTransformation ( const Transformation& transformation ) { _topTransformation = transformation; }
+  inline  void  QueryStack::setThreshold         ( DbU::Unit             threshold )      { _threshold = threshold; }
   inline  void  QueryStack::setStartLevel        ( unsigned int          level )          { _startLevel = level; }
   inline  void  QueryStack::setStopLevel         ( unsigned int          level )          { _stopLevel = level; }
 
@@ -204,6 +207,8 @@ namespace Hurricane {
     QueryState* parent   = *(rbegin()+1);
     Instance*   instance = child->_locator->getElement();
 
+  //cerr << "Processing " << instance << endl;
+
     child->_area           = parent->_area;
     child->_transformation = instance->getTransformation ();
 
@@ -219,7 +224,9 @@ namespace Hurricane {
   {
     if ( size() > _stopLevel ) return false;
 
-    Locator<Instance*>* locator = getMasterCell()->getInstancesUnder(getArea()).getLocator();
+  //cerr << "QueryStack::levelDown(): t:" << DbU::getValueString(getThreshold()) << endl;
+    Locator<Instance*>* locator =
+      getMasterCell()->getInstancesUnder(getArea(),getThreshold()).getLocator();
 
     if ( locator->isValid() ) {
       push_back ( new QueryState ( locator ) );
@@ -231,6 +238,7 @@ namespace Hurricane {
     } else
       delete locator;
 
+  //cerr << "  Aborting level down" << endl;
     return false;
   }
 
@@ -314,6 +322,7 @@ namespace Hurricane {
       inline  size_t                getDepth               () const;
       inline  const Transformation& getTransformation      () const;
       inline  const Box&            getArea                () const;
+      inline  DbU::Unit             getThreshold           () const;
       inline  const BasicLayer*     getBasicLayer          () const;
       inline  Cell*                 getMasterCell          ();
       inline  Instance*             getInstance            ();
@@ -336,9 +345,11 @@ namespace Hurricane {
                                                            , const BasicLayer*     basicLayer
                                                            , ExtensionSlice::Mask  extensionMask
                                                            , Mask                  filter
+                                                           , DbU::Unit             threshold=0
                                                            );
       inline  void                  setCell                ( Cell*                 cell );
       inline  void                  setArea                ( const Box&            area );
+      inline  void                  setThreshold           ( DbU::Unit             threshold );
       inline  void                  setTransformation      ( const Transformation& transformation );
       virtual void                  setBasicLayer          ( const BasicLayer*     basicLayer );
       inline  void                  setExtensionMask       ( ExtensionSlice::Mask  mode );
@@ -360,6 +371,7 @@ namespace Hurricane {
 
   inline  void  Query::setCell           ( Cell*                 cell )           { _stack.setTopCell(cell); }
   inline  void  Query::setArea           ( const Box&            area )           { _stack.setTopArea(area); }
+  inline  void  Query::setThreshold      ( DbU::Unit             threshold )      { _stack.setThreshold(threshold); }
   inline  void  Query::setTransformation ( const Transformation& transformation ) { _stack.setTopTransformation(transformation); }
   inline  void  Query::setFilter         ( Mask                  filter )         { _filter = filter; }
   inline  void  Query::setExtensionMask  ( ExtensionSlice::Mask  mask )           { _extensionMask = mask; }
@@ -379,5 +391,3 @@ namespace Hurricane {
   
 
 } // Hurricane namespace.
-
-#endif // HURRICANE_QUERY_H
diff --git a/hurricane/src/hurricane/hurricane/Slice.h b/hurricane/src/hurricane/hurricane/Slice.h
index 363451bc..60437876 100644
--- a/hurricane/src/hurricane/hurricane/Slice.h
+++ b/hurricane/src/hurricane/hurricane/Slice.h
@@ -17,9 +17,7 @@
 // not, see <http://www.gnu.org/licenses/>.
 // ****************************************************************************************************
 
-#ifndef HURRICANE_SLICE
-#define HURRICANE_SLICE
-
+#pragma  once
 #include "hurricane/QuadTree.h"
 #include "hurricane/Components.h"
 #include "hurricane/Markers.h"
@@ -72,9 +70,9 @@ class Slice {
     public: const Layer* getLayer() const {return _layer;};
     public: const Box& getBoundingBox() const {return _quadTree.getBoundingBox();};
     public: Gos getGos() const {return _quadTree.getGos();};
-    public: Gos getGosUnder(const Box& area) const {return _quadTree.getGosUnder(area);};
+    public: Gos getGosUnder(const Box& area, DbU::Unit threshold=0) const {return _quadTree.getGosUnder(area,threshold);};
     public: Components getComponents() const;
-    public: Components getComponentsUnder(const Box& area) const;
+    public: Components getComponentsUnder(const Box& area, DbU::Unit threshold=0) const;
     public: Markers getMarkers() const;
     public: Markers getMarkersUnder(const Box& area) const;
 
@@ -107,9 +105,6 @@ class Slice {
 INSPECTOR_P_SUPPORT(Hurricane::Slice);
 
 
-#endif // HURRICANE_SLICE
-
-
 // ****************************************************************************************************
 // Copyright (c) BULL S.A. 2000-2018, All Rights Reserved
 // ****************************************************************************************************
diff --git a/hurricane/src/isobar/PyCell.cpp b/hurricane/src/isobar/PyCell.cpp
index b84927e9..aac63430 100644
--- a/hurricane/src/isobar/PyCell.cpp
+++ b/hurricane/src/isobar/PyCell.cpp
@@ -710,6 +710,20 @@ extern "C" {
   }
 
 
+  // ---------------------------------------------------------------
+  // Attribute Method  :  "PyCell_destroyPhysical ()"
+
+  static PyObject* PyCell_destroyPhysical ( PyCell *self )
+  {
+    cdebug_log(20,0) << "PyCell_destroyPhysical ()" << endl;
+    HTRY
+      METHOD_HEAD( "Cell.destroyPhysical()" )
+      cell->destroyPhysical();
+    HCATCH
+    Py_RETURN_NONE;
+  }
+
+
   // Standart Predicates (Attributes).
   DirectGetBoolAttribute(PyCell_isTerminal       , isTerminal       ,PyCell,Cell)
   DirectGetBoolAttribute(PyCell_isTerminalNetlist, isTerminalNetlist,PyCell,Cell)
@@ -766,8 +780,8 @@ extern "C" {
     , { "setRouted"           , (PyCFunction)PyCell_setRouted           , METH_VARARGS, "Sets the cell routed status." }
     , { "uniquify"            , (PyCFunction)PyCell_uniquify            , METH_VARARGS, "Uniquify the Cell and it's instances up to <depth>." }
     , { "getClone"            , (PyCFunction)PyCell_getClone            , METH_NOARGS , "Return a copy of the Cell (placement only)." }
-    , { "destroy"             , (PyCFunction)PyCell_destroy             , METH_NOARGS
-                              , "Destroy associated hurricane object The python object remains." }
+    , { "destroyPhysical"     , (PyCFunction)PyCell_destroyPhysical     , METH_NOARGS , "Destroy all physical components, including DeepNets (vflatten)." }
+    , { "destroy"             , (PyCFunction)PyCell_destroy             , METH_NOARGS , "Destroy associated hurricane object The python object remains." }
     , {NULL, NULL, 0, NULL}   /* sentinel */
     };
 
diff --git a/hurricane/src/viewer/CellWidget.cpp b/hurricane/src/viewer/CellWidget.cpp
index 8ab46913..5e5e30d3 100644
--- a/hurricane/src/viewer/CellWidget.cpp
+++ b/hurricane/src/viewer/CellWidget.cpp
@@ -1348,12 +1348,16 @@ namespace Hurricane {
       if (getCell()) {
         Box redrawBox = screenToDbuBox( redrawArea );
 
+      //cerr << "redrawBox:" << redrawBox << endl;
+      //cerr << "Threshold:" << DbU::getValueString(screenToDbuLength(20)) << endl;
+
         _drawingQuery.resetGoCount         ();
         _drawingQuery.resetExtensionGoCount();
         _drawingQuery.resetInstanceCount   ();
         _drawingQuery.setExtensionMask     ( 0 );
         _drawingQuery.setArea              ( redrawBox );
         _drawingQuery.setTransformation    ( Transformation() );
+        _drawingQuery.setThreshold         ( screenToDbuLength(20) );
 
         for ( BasicLayer* layer : _technology->getBasicLayers() ) {
           _drawingPlanes.setPen  ( Graphics::getPen  (layer->getName(),getDarkening()) );
diff --git a/hurricane/src/viewer/hurricane/viewer/CellWidget.h b/hurricane/src/viewer/hurricane/viewer/CellWidget.h
index 6d26f7be..338a0f95 100644
--- a/hurricane/src/viewer/hurricane/viewer/CellWidget.h
+++ b/hurricane/src/viewer/hurricane/viewer/CellWidget.h
@@ -14,9 +14,7 @@
 // +-----------------------------------------------------------------+
 
 
-#ifndef  HURRICANE_CELL_WIDGET_H
-#define  HURRICANE_CELL_WIDGET_H
-
+#pragma  once
 #include <math.h>
 #include <vector>
 #include <functional>
@@ -1470,6 +1468,3 @@ namespace Hurricane {
 
 GETSTRING_POINTER_SUPPORT(Hurricane::CellWidget);
 IOSTREAM_POINTER_SUPPORT(Hurricane::CellWidget);
-
-
-#endif  // HURRICANE_CELL_WIDGET