diff --git a/Apps/SandBox/wallPaper.cpp b/Apps/SandBox/wallPaper.cpp
index 04112b41eee7c8e34baa358393689e04e5867e3c..0cdc7c9e2aff560d2f5f6768a03f1c6d8b460f98 100644
--- a/Apps/SandBox/wallPaper.cpp
+++ b/Apps/SandBox/wallPaper.cpp
@@ -43,7 +43,7 @@ void MyQT::cb_initGL()
 	m_render = new Algo::Render::GL2::MapRender();
 
 	// create VBO for position
-	m_positionVBO = new Utils::VBO();
+	m_positionVBO = new Utils::VBO(&converterDF);
 	m_positionVBO->updateData(position);
 
 	m_shader = new Utils::ShaderSimpleColor();
diff --git a/Apps/SandBox/wallPaper.h b/Apps/SandBox/wallPaper.h
index f0b58aaf0b0ae375890a0cabe73ea9e01b6a088e..52c2e9895a53c96e5cc63a25064bec200601cd1c 100644
--- a/Apps/SandBox/wallPaper.h
+++ b/Apps/SandBox/wallPaper.h
@@ -46,7 +46,7 @@
 using namespace CGoGN ;
 
 
-struct PFP: public PFP_STANDARD
+struct PFP: public PFP_DOUBLE
 {
 	// definition of the map
 	typedef EmbeddedMap2 MAP ;
@@ -67,7 +67,11 @@ public:
 	VertexAttribute<VEC3, MAP> position ;
 
     Algo::Render::GL2::MapRender* m_render;
+
+	// converter for automatic conversion when updating VBOs
+	ConvertVec3dToVec3f converterDF;
     Utils::VBO* m_positionVBO;
+
     Utils::ShaderSimpleColor* m_shader;
 
 	// FOR WALL PAPER
diff --git a/include/Container/convert.h b/include/Container/convert.h
index 8fadfabe56899ed7273dd2fc8bc9d9d29d1b5f38..5495084789bdfd5319a11e063e69991e4aced0cb 100644
--- a/include/Container/convert.h
+++ b/include/Container/convert.h
@@ -319,7 +319,8 @@ protected:
 
 public:
 	ConvertVec3dToVec3f():
-		ConvertBuffer(sizeof(Geom::Vec3d))
+		ConvertBuffer(sizeof(Geom::Vec3d)),
+		m_typedBuffer(NULL)
 	{}
 
 	~ConvertVec3dToVec3f()
@@ -349,15 +350,14 @@ public:
 	{
 		// cast ptr in & out with right type
 		const Geom::Vec3d* typedIn = reinterpret_cast<const Geom::Vec3d*>(ptrIn);
-		Geom::Vec3f* typedOut = reinterpret_cast<Geom::Vec3f*>(m_buffer);
+		Geom::Vec3f* typedOut = m_typedBuffer;
 		// compute conversion
 		for (unsigned int i = 0; i < m_nb; ++i)
 		{
 			const Geom::Vec3d& vd = *typedIn++;
 			*typedOut++ = Geom::Vec3f(float(vd[0]),float(vd[1]),float(vd[2]));
-//			Geom::Vec3f& vf = *typedOut++;
-//			vf[0]=vd[0];vf[1]=vd[1];vf[2]=vd[2];
 		}
+
 	}
 
 	unsigned int vectorSize()
diff --git a/include/Utils/Qt/qtQGLV.h b/include/Utils/Qt/qtQGLV.h
index 6bf1cea8f869d88021b43378103fca684ec21d6c..956a1453f6f4dc5361de9a72b44174f44d4b6cc6 100644
--- a/include/Utils/Qt/qtQGLV.h
+++ b/include/Utils/Qt/qtQGLV.h
@@ -193,12 +193,35 @@ public:
 	/**
 	 * set width and pos center of object to draw
 	 */
-	void setParamObject(float width, float* pos) { m_qglWidget->setParamObject(width, pos); }
+	template<typename T>
+	inline void setParamObject(T width, T* pos)
+	{
+		float posF[3];
+		posF[0]=float(pos[0]);
+		posF[1]=float(pos[1]);
+		posF[2]=float(pos[2]);
+		m_qglWidget->setParamObject(float(width), posF);
+	}
+
 
 	/**
 	 * set BB min & max corner of object to draw
 	 */
-	void setObjectBB(float* bbmin, float* bbmax) { m_qglWidget->setObjectBB(bbmin, bbmax); }
+	inline void setObjectBB(float* bbmin, float* bbmax) { m_qglWidget->setObjectBB(bbmin, bbmax); }
+
+	template <typename T>
+	void setObjectBB(T* bbmin, T* bbmax)
+	{
+		float bbminF[3];
+		bbminF[0]=float(bbmin[0]);
+		bbminF[1]=float(bbmin[1]);
+		bbminF[2]=float(bbmin[2]);
+		float bbmaxF[3];
+		bbmaxF[0]=float(bbmax[0]);
+		bbmaxF[1]=float(bbmax[1]);
+		bbmaxF[2]=float(bbmax[2]);
+		m_qglWidget->setObjectBB(bbminF, bbmaxF);
+	}
 
 	/**
 	 * @brief get pointer on QGLViewer widget for direct access
diff --git a/include/Utils/Qt/qtSimple.h b/include/Utils/Qt/qtSimple.h
index 9ebea2b5a06daec2245f6e81e4de5395572ac292..c62b4100495daac683bd52c86c3a2565d1a63bfc 100644
--- a/include/Utils/Qt/qtSimple.h
+++ b/include/Utils/Qt/qtSimple.h
@@ -195,9 +195,26 @@ public:
 	/**
 	 * set width and pos center of object to draw
 	 */
-	void setParamObject(float width, float* pos) { m_glWidget->setParamObject(width, pos); }
+	template<typename T>
+	inline void setParamObject(T width, T* pos)
+	{
+		float posF[3];
+		posF[0]=float(pos[0]);
+		posF[1]=float(pos[1]);
+		posF[2]=float(pos[2]);
+		m_glWidget->setParamObject(float(width), posF);
+	}
+
+	template<typename T>
+	inline void resetCenterOfRotation(T width, T* pos)
+	{
+		float posF[3];
+		posF[0]=float(pos[0]);
+		posF[1]=float(pos[1]);
+		posF[2]=float(pos[2]);
+		m_glWidget->resetCenterOfRotation(float(width), posF);
+	}
 
-	void resetCenterOfRotation(float width, float* pos) { m_glWidget->resetCenterOfRotation(width, pos); }
 
 	/**
 	 * make the contex of glWidget current
diff --git a/src/Utils/vbo.cpp b/src/Utils/vbo.cpp
index aac1b062bbd29eab4fae01567caa91066d4ad2b8..8a63a3d01373b65215b11bc460818cede6589a86 100644
--- a/src/Utils/vbo.cpp
+++ b/src/Utils/vbo.cpp
@@ -131,8 +131,6 @@ void VBO::updateData_withConversion(const AttributeMultiVectorGen* attrib, Conve
 
 	m_name = attrib->getName();
 	m_typeName = attrib->getTypeName();
-
-//	m_data_size = attrib->getSizeOfType() / conv->sizeElt();
 	m_data_size = conv->vectorSize();
 
 	// alloue la memoire pour le buffer et initialise le conv
@@ -142,7 +140,7 @@ void VBO::updateData_withConversion(const AttributeMultiVectorGen* attrib, Conve
 	unsigned int byteTableSize;
 	unsigned int nbb = attrib->getBlocksPointers(addr, byteTableSize);
 
-	m_nbElts = nbb * attrib->getBlockSize()*m_data_size;
+//	m_nbElts = nbb * attrib->getBlockSize()/m_data_size;
 
 	// bind buffer to update
 	glBindBuffer(GL_ARRAY_BUFFER, *m_id);