diff --git a/include/Algo/ImplicitHierarchicalMesh/ihm3.h b/include/Algo/ImplicitHierarchicalMesh/ihm3.h
index 5022a361dc8dc2a5f74a58d3da16da80cfd2dd4a..80566aa6872404e1ab733d1b4f028fec328b0fc2 100644
--- a/include/Algo/ImplicitHierarchicalMesh/ihm3.h
+++ b/include/Algo/ImplicitHierarchicalMesh/ihm3.h
@@ -137,6 +137,12 @@ public:
 	 */
 	void constructSplittingPath(Dart d, std::vector<Dart>& v, DartMarker& m);
 
+	//!
+	/*!
+	 *
+	 */
+	void swapEdges(Dart d, Dart e);
+
 //	//!
 //	/*!
 //	 *
diff --git a/include/Algo/ImplicitHierarchicalMesh/subdivision3.hpp b/include/Algo/ImplicitHierarchicalMesh/subdivision3.hpp
index 8a284adfbe92e22c4d236a3f4a87f62b43db18ff..59322fe3b2debf4647d3df0005c8e5b33cd21c22 100644
--- a/include/Algo/ImplicitHierarchicalMesh/subdivision3.hpp
+++ b/include/Algo/ImplicitHierarchicalMesh/subdivision3.hpp
@@ -639,7 +639,7 @@ void subdivideLoop(typename PFP::MAP& map, Dart d, typename PFP::TVEC3& position
 	{
 		//volCenter += position[d];
 		//++degree;
-
+		Dart f1 = map.phi1(dit);
 		Dart e = dit;
 		std::vector<Dart> v ;
 
@@ -684,17 +684,17 @@ void subdivideLoop(typename PFP::MAP& map, Dart d, typename PFP::TVEC3& position
 			}
 			while(dd != stop);
 		}
-//		else
-//		{
-//			unsigned int idface = map.getNewFaceId();
-//			map.setFaceId(map.phi2(f1),idface, FACE);
-//		}
+		else
+		{
+			unsigned int idface = map.getNewFaceId();
+			map.setFaceId(map.phi2(v.front()),idface, FACE);
+		}
 	}
 
 	//switch inner faces
 	if(isNotTet)
 	{
-		unsigned int i = 0;
+		DartMarker me(map);
 
 		for(Dart dit = traV.begin(); dit != traV.end(); dit = traV.next())
 		{
@@ -704,58 +704,56 @@ void subdivideLoop(typename PFP::MAP& map, Dart d, typename PFP::TVEC3& position
 			do
 			{
 				Dart f3 = map.phi3(f);
-				Dart tmp =  map.phi_1(map.phi2(map.phi_1(map.phi2(map.phi_1(f3))))); //future voisin par phi2
 
-				map.unsewFaces(f3);
-				map.unsewFaces(tmp);
-				map.sewFaces(f3, tmp, false);
+				if(!me.isMarked(f3))
+				{
+					Dart tmp =  map.phi_1(map.phi2(map.phi_1(map.phi2(map.phi_1(f3))))); //future voisin par phi2
 
-				map.copyDartEmbedding(VERTEX, map.phi2(f3), tmp);
-				map.copyDartEmbedding(VERTEX, map.phi2(tmp), f3);
+					Dart f32 = map.phi2(f3);
+					map.swapEdges(f3, tmp);
 
-//				map.embedOrbit(VERTEX, f3, map.getEmbedding(VERTEX, f3)) ;
-//				map.embedOrbit(VERTEX, tmp, map.getEmbedding(VERTEX, tmp)) ;
+					unsigned int idface = map.getNewFaceId();
+					map.setFaceId(map.phi2(f3),idface, FACE);
+
+					me.markOrbit(EDGE, f3);
+					me.markOrbit(EDGE, f32);
+				}
 
-//				unsigned int idface = map.getNewFaceId();
-//				map.setFaceId(map.phi2(f3),idface, FACE);
 				f = map.phi2(map.phi_1(f));
 			}while(f != x);
-
 		}
+
 	}
 
-	position[centralDart] = volCenter;
+	//Third step : 3-sew internal faces
+	for (std::vector<std::pair<Dart,Dart> >::iterator it = subdividedfaces.begin(); it != subdividedfaces.end(); ++it)
+	{
+		Dart f1 = (*it).first;
+		Dart f2 = (*it).second;
 
+		//FAIS a la couture !!!!!!!
+		//id pour toutes les aretes exterieurs des faces quadrangulees
+		unsigned int idedge = map.getEdgeId(f1);
+		map.setEdgeId(map.phi2(f1), idedge, DART);
+		map.setEdgeId( map.phi2(f2), idedge, DART);
 
-//		//Third step : 3-sew internal faces
-//		for (std::vector<std::pair<Dart,Dart> >::iterator it = subdividedfaces.begin(); it != subdividedfaces.end(); ++it)
-//		{
-//			Dart f1 = (*it).first;
-//			Dart f2 = (*it).second;
-//
-//			//FAIS a la couture !!!!!!!
-//			//id pour toutes les aretes exterieurs des faces quadrangulees
-//			unsigned int idedge = map.getEdgeId(f1);
-//			map.setEdgeId(map.phi2(f1), idedge, DART);
-//			map.setEdgeId( map.phi2(f2), idedge, DART);
-//
-//		}
-//
-//		//LA copie de L'id est a gerer avec le sewVolumes normalement !!!!!!
-//		//id pour les aretes interieurs : (i.e. 16 pour un octa)
-//		DartMarker mne(map);
-//		for(std::vector<Dart>::iterator it = newEdges.begin() ; it != newEdges.end() ; ++it)
-//		{
-//			if(!mne.isMarked(*it))
-//			{
-//				unsigned int idedge = map.getNewEdgeId();
-//				map.setEdgeId(*it, idedge, EDGE);
-//				mne.markOrbit(EDGE,*it);
-//			}
-//		}
-//
-//
-//		map.setCurrentLevel(cur) ;
+	}
+
+	//LA copie de L'id est a gerer avec le sewVolumes normalement !!!!!!
+	//id pour les aretes interieurs : (i.e. 16 pour un octa)
+	DartMarker mne(map);
+	for(std::vector<Dart>::iterator it = newEdges.begin() ; it != newEdges.end() ; ++it)
+	{
+		if(!mne.isMarked(*it))
+		{
+			unsigned int idedge = map.getNewEdgeId();
+			map.setEdgeId(*it, idedge, EDGE);
+			mne.markOrbit(EDGE,*it);
+		}
+	}
+
+
+		map.setCurrentLevel(cur) ;
 }
 
 
diff --git a/include/Algo/Modelisation/polyhedron.hpp b/include/Algo/Modelisation/polyhedron.hpp
index 92a7d77d18d3094e2e067975944ad9bbc6dfaa8c..4c671f8a6290ae8abe5fe5420c965aa796a255f8 100644
--- a/include/Algo/Modelisation/polyhedron.hpp
+++ b/include/Algo/Modelisation/polyhedron.hpp
@@ -139,7 +139,7 @@ Dart createDiamond(typename PFP::MAP& map, unsigned int nbSides)
 	res = map.phi2(firstP);
 
 	map.sewVolumes(firstP, secondP);
-	map.mergeVolumes(firstP);
+	//map.mergeVolumes(firstP);
 
 	return res;
 }
diff --git a/include/Algo/Render/GL2/explodeVolumeRender.h b/include/Algo/Render/GL2/explodeVolumeRender.h
index 9b897b2a88bd800453d670b7714cd508849fc471..82c32674fe6095970ab59f4a47d96e1a15d8826b 100644
--- a/include/Algo/Render/GL2/explodeVolumeRender.h
+++ b/include/Algo/Render/GL2/explodeVolumeRender.h
@@ -108,8 +108,8 @@ public:
 	* @param positions  attribute of position vertices
 	* @param good selector
 	*/
-//	template<typename PFP>
-//	void updateData(typename PFP::MAP& map, typename PFP::TVEC3& positions, const FunctorSelect& good = allDarts) ;
+	template<typename PFP>
+	void updateData(typename PFP::MAP& map, typename PFP::TVEC3& positions, const FunctorSelect& good = allDarts) ;
 
 	/**
 	* update all drawing buffers
diff --git a/include/Algo/Render/GL2/explodeVolumeRender.hpp b/include/Algo/Render/GL2/explodeVolumeRender.hpp
index 2518326374c8ce98ebf7569750f3781ad4ad2e12..2be03dfa177d439de1d035a89f60a7b7f9912d23 100644
--- a/include/Algo/Render/GL2/explodeVolumeRender.hpp
+++ b/include/Algo/Render/GL2/explodeVolumeRender.hpp
@@ -75,103 +75,103 @@ inline ExplodeVolumeRender::~ExplodeVolumeRender()
 	delete m_shaderL;
 }
 
-//template<typename PFP>
-//void ExplodeVolumeRender::updateData(typename PFP::MAP& map, typename PFP::TVEC3& positions, const FunctorSelect& good)
-//{
-//	if (m_cpf)
-//	{
-//		CGoGNerr<< "ExplodeVolumeRender: problem wrong update fonction use the other" << CGoGNendl;
-//		return;
-//	}
-//
-//	typedef typename PFP::VEC3 VEC3;
-//	typedef typename PFP::REAL REAL;
-//
-//	CellMarker cmv(map,VOLUME);
-//	AutoAttributeHandler<VEC3> centerVolumes(map,VOLUME,"centerVolumes");
-//	TraversorW<typename PFP::MAP> traVol(map,good);
-//	for (Dart d=traVol.begin(); d!=traVol.end(); d=traVol.next())
-//	{
-//		centerVolumes[d] = Algo::Geometry::volumeCentroid<PFP>(map, d, positions);
-//	}
-//
-//	std::vector<VEC3> buffer;
-//	buffer.reserve(16384);
-//
-//
-//	TraversorCell<typename PFP::MAP> traFace(map, PFP::MAP::ORBIT_IN_PARENT(FACE),good);
-//
-//	for (Dart d=traFace.begin(); d!=traFace.end(); d=traFace.next())
-//	{
-//		if (m_ef)
-//		{
-//			VEC3 centerFace = Algo::Geometry::faceCentroid<PFP>(map,d,positions);
-//			Dart a = d;
-//			Dart b = map.phi1(a);
-//			Dart c = map.phi1(b);
-//
-//			// loop to cut a polygon in triangle on the fly (works only with convex faces)
-//			do
-//			{
-//				buffer.push_back(centerVolumes[d]);
-//				buffer.push_back(positions[d]);
-//				buffer.push_back(positions[b]);
-//				buffer.push_back(positions[c]);
-//				buffer.push_back(centerFace); // not used
-//				buffer.push_back(centerFace);
-//				b = c;
-//				c = map.phi1(b);
-//
-//			} while (c != d);
-//		}
-//		else
-//		{
-//			Dart a = d;
-//			Dart b = map.phi1(a);
-//			Dart c = map.phi1(b);
-//
-//			// loop to cut a polygon in triangle on the fly (works only with convex faces)
-//			do
-//			{
-//				buffer.push_back(centerVolumes[d]);
-//				buffer.push_back(positions[d]);
-//				buffer.push_back(positions[b]);
-//				buffer.push_back(positions[c]);
-//				b = c;
-//				c = map.phi1(b);
-//
-//			} while (c != d);
-//		}
-//	}
-//
-//	m_nbTris = buffer.size()/4;
-//
-//	m_vboPos->allocate(buffer.size());
-//	VEC3* ptrPos = reinterpret_cast<VEC3*>(m_vboPos->lockPtr());
-//	memcpy(ptrPos,&buffer[0],buffer.size()*sizeof(VEC3));
-//	m_vboPos->releasePtr();
-//	m_shader->setAttributePosition(m_vboPos);
-//
-//	buffer.clear();
-//
-//	TraversorCell<typename PFP::MAP> traEdge(map, PFP::MAP::ORBIT_IN_PARENT(EDGE),good);
-//	for (Dart d=traEdge.begin(); d!=traEdge.end(); d=traEdge.next())
-//	{
-//			buffer.push_back(centerVolumes[d]);
-//			buffer.push_back(positions[d]);
-//			buffer.push_back(positions[ map.phi1(d)]);
-//	}
-//
-//	m_nbLines = buffer.size()/3;
-//
-//	m_vboPosLine->allocate(buffer.size());
-//
-//	ptrPos = reinterpret_cast<VEC3*>(m_vboPosLine->lockPtr());
-//	memcpy(ptrPos,&buffer[0],buffer.size()*sizeof(VEC3));
-//
-//	m_vboPosLine->releasePtr();
-//	m_shaderL->setAttributePosition(m_vboPosLine);
-//}
+template<typename PFP>
+void ExplodeVolumeRender::updateData(typename PFP::MAP& map, typename PFP::TVEC3& positions, const FunctorSelect& good)
+{
+	if (m_cpf)
+	{
+		CGoGNerr<< "ExplodeVolumeRender: problem wrong update fonction use the other" << CGoGNendl;
+		return;
+	}
+
+	typedef typename PFP::VEC3 VEC3;
+	typedef typename PFP::REAL REAL;
+
+	CellMarker cmv(map,VOLUME);
+	AutoAttributeHandler<VEC3> centerVolumes(map,VOLUME,"centerVolumes");
+	TraversorW<typename PFP::MAP> traVol(map,good);
+	for (Dart d=traVol.begin(); d!=traVol.end(); d=traVol.next())
+	{
+		centerVolumes[d] = Algo::Geometry::volumeCentroid<PFP>(map, d, positions);
+	}
+
+	std::vector<VEC3> buffer;
+	buffer.reserve(16384);
+
+
+	TraversorCell<typename PFP::MAP> traFace(map, PFP::MAP::ORBIT_IN_PARENT(FACE),good);
+
+	for (Dart d=traFace.begin(); d!=traFace.end(); d=traFace.next())
+	{
+		if (m_ef)
+		{
+			VEC3 centerFace = Algo::Geometry::faceCentroid<PFP>(map,d,positions);
+			Dart a = d;
+			Dart b = map.phi1(a);
+			Dart c = map.phi1(b);
+
+			// loop to cut a polygon in triangle on the fly (works only with convex faces)
+			do
+			{
+				buffer.push_back(centerVolumes[d]);
+				buffer.push_back(positions[d]);
+				buffer.push_back(positions[b]);
+				buffer.push_back(positions[c]);
+				buffer.push_back(centerFace); // not used
+				buffer.push_back(centerFace);
+				b = c;
+				c = map.phi1(b);
+
+			} while (c != d);
+		}
+		else
+		{
+			Dart a = d;
+			Dart b = map.phi1(a);
+			Dart c = map.phi1(b);
+
+			// loop to cut a polygon in triangle on the fly (works only with convex faces)
+			do
+			{
+				buffer.push_back(centerVolumes[d]);
+				buffer.push_back(positions[d]);
+				buffer.push_back(positions[b]);
+				buffer.push_back(positions[c]);
+				b = c;
+				c = map.phi1(b);
+
+			} while (c != d);
+		}
+	}
+
+	m_nbTris = buffer.size()/4;
+
+	m_vboPos->allocate(buffer.size());
+	VEC3* ptrPos = reinterpret_cast<VEC3*>(m_vboPos->lockPtr());
+	memcpy(ptrPos,&buffer[0],buffer.size()*sizeof(VEC3));
+	m_vboPos->releasePtr();
+	m_shader->setAttributePosition(m_vboPos);
+
+	buffer.clear();
+
+	TraversorCell<typename PFP::MAP> traEdge(map, PFP::MAP::ORBIT_IN_PARENT(EDGE),good);
+	for (Dart d=traEdge.begin(); d!=traEdge.end(); d=traEdge.next())
+	{
+			buffer.push_back(centerVolumes[d]);
+			buffer.push_back(positions[d]);
+			buffer.push_back(positions[ map.phi1(d)]);
+	}
+
+	m_nbLines = buffer.size()/3;
+
+	m_vboPosLine->allocate(buffer.size());
+
+	ptrPos = reinterpret_cast<VEC3*>(m_vboPosLine->lockPtr());
+	memcpy(ptrPos,&buffer[0],buffer.size()*sizeof(VEC3));
+
+	m_vboPosLine->releasePtr();
+	m_shaderL->setAttributePosition(m_vboPosLine);
+}
 
 
 template<typename PFP>
diff --git a/include/Topology/generic/traversorCell.h b/include/Topology/generic/traversorCell.h
index 4c3f1dfad35691f3eff0f80847b6e0e6b5b73555..0f1883c5646a4a3def6db3996d013734705bd951 100644
--- a/include/Topology/generic/traversorCell.h
+++ b/include/Topology/generic/traversorCell.h
@@ -62,7 +62,7 @@ template <typename MAP>
 class TraversorV : public TraversorCell<MAP>
 {
 public:
-	TraversorV(MAP& m, const FunctorSelect& good = allDarts, unsigned int thread = 0) : TraversorCell<MAP>(m, VERTEX, good, thread)
+	TraversorV(MAP& m, const FunctorSelect& good = allDarts, bool forceDartMarker = false, unsigned int thread = 0) : TraversorCell<MAP>(m, VERTEX, good, forceDartMarker, thread)
 	{}
 };
 
@@ -70,7 +70,7 @@ template <typename MAP>
 class TraversorE : public TraversorCell<MAP>
 {
 public:
-	TraversorE(MAP& m, const FunctorSelect& good = allDarts, unsigned int thread = 0) : TraversorCell<MAP>(m, EDGE, good, thread)
+	TraversorE(MAP& m, const FunctorSelect& good = allDarts, bool forceDartMarker = false, unsigned int thread = 0) : TraversorCell<MAP>(m, EDGE, good, forceDartMarker, thread)
 	{}
 };
 
@@ -79,7 +79,7 @@ template <typename MAP>
 class TraversorF : public TraversorCell<MAP>
 {
 public:
-	TraversorF(MAP& m, const FunctorSelect& good = allDarts, unsigned int thread = 0) : TraversorCell<MAP>(m, FACE, good, thread)
+	TraversorF(MAP& m, const FunctorSelect& good = allDarts, bool forceDartMarker = false, unsigned int thread = 0) : TraversorCell<MAP>(m, FACE, good, forceDartMarker, thread)
 	{}
 };
 
@@ -87,7 +87,7 @@ template <typename MAP>
 class TraversorW : public TraversorCell<MAP>
 {
 public:
-	TraversorW(MAP& m, const FunctorSelect& good = allDarts, unsigned int thread = 0) : TraversorCell<MAP>(m, VOLUME, good, thread)
+	TraversorW(MAP& m, const FunctorSelect& good = allDarts, bool forceDartMarker = false, unsigned int thread = 0) : TraversorCell<MAP>(m, VOLUME, good, forceDartMarker, thread)
 	{}
 };
 
diff --git a/include/Topology/map/embeddedMap3.h b/include/Topology/map/embeddedMap3.h
index 7864be263cd3aa221a877e1ae7e762e4cd0ccfac..52390ee09a8b7d1aa522e432cc935f491493fe85 100644
--- a/include/Topology/map/embeddedMap3.h
+++ b/include/Topology/map/embeddedMap3.h
@@ -68,6 +68,11 @@ public:
 	 */
 	virtual Dart collapseEdge(Dart d, bool delDegenerateVolumes=true);
 
+	//!
+	/*!
+	 */
+	virtual bool collapseDegeneratedFace(Dart d);
+
 	//!
 	/*!
 	 */
diff --git a/include/Topology/map/map3.h b/include/Topology/map/map3.h
index 2c555b46958e776172b50e5b86579279476adb57..d581958f185a22301903ba414e4d2d8e80ebc455 100644
--- a/include/Topology/map/map3.h
+++ b/include/Topology/map/map3.h
@@ -170,6 +170,14 @@ public:
 	 */
 	virtual Dart collapseEdge(Dart d, bool delDegenerateVolumes = true);
 
+	//! Delete a face if and only if it has one or two edges
+	/*! If the face is sewed to two distinct adjacent faces,
+	 *  then those two faces are sewed
+	 *  @param d a dart of the face
+	 *  @return true if the collapse has been executed, false otherwise
+	 */
+	virtual bool collapseDegeneratedFace(Dart d);
+
 	//! Split a face inserting an edge between two vertices
 	/*! \pre Dart d and e should belong to the same face and be distinct
 	 *  @param d dart of first vertex
diff --git a/src/Algo/ImplicitHierarchicalMesh/ihm3.cpp b/src/Algo/ImplicitHierarchicalMesh/ihm3.cpp
index 7cf79118c9bca203266f0bb48ed6dc31a0962114..01968cef509c75cbfea0d287e7e19c17b3838811 100644
--- a/src/Algo/ImplicitHierarchicalMesh/ihm3.cpp
+++ b/src/Algo/ImplicitHierarchicalMesh/ihm3.cpp
@@ -155,6 +155,36 @@ void ImplicitHierarchicalMap3::constructSplittingPath(Dart d, std::vector<Dart>&
 
 }
 
+
+void ImplicitHierarchicalMap3::swapEdges(Dart d, Dart e)
+{
+	Dart d2 = phi2(d);
+	Dart e2 = phi2(e);
+
+	Map2::unsewFaces(d);
+	Map2::unsewFaces(e);
+
+	Map2::sewFaces(d, e);
+	Map2::sewFaces(d2, e2);
+
+	if(isOrbitEmbedded(VERTEX))
+	{
+		copyDartEmbedding(VERTEX, d, phi2(phi_1(d)));
+		copyDartEmbedding(VERTEX, e, phi2(phi_1(e)));
+		copyDartEmbedding(VERTEX, d2, phi2(phi_1(d2)));
+		copyDartEmbedding(VERTEX, e2, phi2(phi_1(d2)));
+	}
+
+	if(isOrbitEmbedded(EDGE))
+	{
+
+	}
+
+	if(isOrbitEmbedded(VOLUME))
+		embedNewCell(VOLUME, d);
+}
+
+
 //Dart ImplicitHierarchicalMap3::cutEdge(Dart d)
 //{
 //        Dart resV = EmbeddedMap3::cutEdge(d);
diff --git a/src/Topology/map/embeddedMap3.cpp b/src/Topology/map/embeddedMap3.cpp
index 5df84bc9305b87df3c38e79fbd9d351b984d0a5e..039875c0de9b64d3945c8f52b2a2e21bd455cf12 100644
--- a/src/Topology/map/embeddedMap3.cpp
+++ b/src/Topology/map/embeddedMap3.cpp
@@ -154,6 +154,11 @@ Dart EmbeddedMap3::collapseEdge(Dart d, bool delDegenerateVolumes)
 	return resV;
 }
 
+bool EmbeddedMap3::collapseDegeneratedFace(Dart d)
+{
+	return Map3::collapseDegeneratedFace(d);
+}
+
 void EmbeddedMap3::splitFace(Dart d, Dart e)
 {
 	Dart dd = phi1(phi3(d));
diff --git a/src/Topology/map/map3.cpp b/src/Topology/map/map3.cpp
index 5b50c08dd3daf0a8820689a9899355368f0f9e38..0c6b7b85b2a28e23329df7cee4eb29c282b60cfe 100644
--- a/src/Topology/map/map3.cpp
+++ b/src/Topology/map/map3.cpp
@@ -355,7 +355,18 @@ Dart Map3::collapseEdge(Dart d, bool delDegenerateVolumes)
 //		}
 //	}
 
+bool Map3::collapseDegeneratedFace(Dart d)
+{
+	Dart d3 = phi3(d);
+
+	Map3::unsewVolumes(d);
 
+	std::cout << Map2::collapseDegeneratedFace(d) << std::endl;
+	std::cout << Map2::collapseDegeneratedFace(d3) << std::endl;
+	std::cout << std::endl;
+
+	return true;
+}
 
 void Map3::splitFace(Dart d, Dart e)
 {