diff --git a/include/Algo/Render/GL2/topo3PrimalRender.h b/include/Algo/Render/GL2/topo3PrimalRender.h
index 6677b19a1b429fb401688a9d52fe94938e146cf3..d9fb96d3194e471d2dfc5b8eff95f5868772c746 100644
--- a/include/Algo/Render/GL2/topo3PrimalRender.h
+++ b/include/Algo/Render/GL2/topo3PrimalRender.h
@@ -106,6 +106,11 @@ protected:
 	 */
 	Geom::Vec3f m_dartsColor;
 
+	/**
+	 * initial darts color for boundary (set in update)
+	 */
+	Geom::Vec3f m_boundaryDartsColor;
+
 	/**
 	 * attribute index to get easy correspondence dart/color
 	 */
@@ -203,6 +208,8 @@ public:
 	 */
 	void setInitialDartsColor(float r, float g, float b);
 
+	void setInitialBoundaryDartsColor(float r, float g, float b);
+
 	/**
 	 * overdraw a dart with given width and color
 	 * @param d the dart
diff --git a/include/Algo/Render/GL2/topo3PrimalRender.hpp b/include/Algo/Render/GL2/topo3PrimalRender.hpp
index a8c8736a930ef3cbc1ee69ee579806362808c469..8172be643cce12d2a8000d54df6d7f3449eb60de 100644
--- a/include/Algo/Render/GL2/topo3PrimalRender.hpp
+++ b/include/Algo/Render/GL2/topo3PrimalRender.hpp
@@ -56,27 +56,24 @@ void Topo3PrimalRender::setDartsIdColor(typename PFP::MAP& map)
 
 	for (Dart d = map.begin(); d != map.end(); map.next(d))
 	{
-		if ( !map.isBoundaryMarked3(d)) // topo3 Render do not traverse boundary
+		if (nb < m_nbDarts)
 		{
-			if (nb < m_nbDarts)
-			{
-				float r,g,b;
-				dartToCol(d, r,g,b);
-
-				float* local = colorBuffer+3*m_attIndex[d]; // get the right position in VBO
-				*local++ = r;
-				*local++ = g;
-				*local++ = b;
-				*local++ = r;
-				*local++ = g;
-				*local++ = b;
-				nb++;
-			}
-			else
-			{
-				CGoGNerr << "Error buffer too small for color picking (change the selector parameter ?)" << CGoGNendl;
-				break;
-			}
+			float r,g,b;
+			dartToCol(d, r,g,b);
+
+			float* local = colorBuffer+3*m_attIndex[d]; // get the right position in VBO
+			*local++ = r;
+			*local++ = g;
+			*local++ = b;
+			*local++ = r;
+			*local++ = g;
+			*local++ = b;
+			nb++;
+		}
+		else
+		{
+			CGoGNerr << "Error buffer too small for color picking (change the selector parameter ?)" << CGoGNendl;
+			break;
 		}
 	}
 	glUnmapBuffer(GL_ARRAY_BUFFER);
@@ -91,18 +88,15 @@ void Topo3PrimalRender::updateColors(typename PFP::MAP& map, const VertexAttribu
 
 	for (Dart d = map.begin(); d != map.end(); map.next(d))
 	{
-		if ( !map.isBoundaryMarked3(d)) // topo3 Render do not traverse boundary
+		if (nb < m_nbDarts)
 		{
-			if (nb < m_nbDarts)
-			{
-				colorBuffer[m_attIndex[d]] = colors[d];
-				nb++;
-			}
-			else
-			{
-				CGoGNerr << "Error buffer too small for color picking (change the selector parameter ?)" << CGoGNendl;
-				break;
-			}
+			colorBuffer[m_attIndex[d]] = colors[d];
+			nb++;
+		}
+		else
+		{
+			CGoGNerr << "Error buffer too small for color picking (change the selector parameter ?)" << CGoGNendl;
+			break;
 		}
 	}
 	glUnmapBuffer(GL_ARRAY_BUFFER);
@@ -198,22 +192,40 @@ void Topo3PrimalRender::updateData(typename PFP::MAP& mapx, const VertexAttribut
 
 			*positionDartBuf++ = P;
 			*positionDartBuf++ = PP;
-			*positionDartBuf++ = Q;
-			*positionDartBuf++ = QQ;
-			*colorDartBuf++ = m_dartsColor;
-			*colorDartBuf++ = m_dartsColor;
-			*colorDartBuf++ = m_dartsColor;
-			*colorDartBuf++ = m_dartsColor;
+			if (map.isBoundaryMarked3(d))
+			{
+				*colorDartBuf++ = m_boundaryDartsColor;
+				*colorDartBuf++ = m_boundaryDartsColor;
+			}
+			else
+			{
+				*colorDartBuf++ = m_dartsColor;
+				*colorDartBuf++ = m_dartsColor;
+			}
 
 			m_attIndex[d] = posDBI;
 			posDBI+=2;
-
 			fv2[d] = (P+PP)*0.5f;
+
+
+			*positionDartBuf++ = Q;
+			*positionDartBuf++ = QQ;
+
 			Dart dx = map.phi3(d);
-			fv2[dx] = (Q+QQ)*0.5f;
+			if (map.isBoundaryMarked3(dx))
+			{
+				*colorDartBuf++ = m_boundaryDartsColor;
+				*colorDartBuf++ = m_boundaryDartsColor;
+			}
+			else
+			{
+				*colorDartBuf++ = m_dartsColor;
+				*colorDartBuf++ = m_dartsColor;
+			}
 
 			m_attIndex[dx] = posDBI;
 			posDBI+=2;
+			fv2[dx] = (Q+QQ)*0.5f;
 
 			d = mapx.phi1(d);
 		}
diff --git a/src/Algo/Render/topo3PrimalRender.cpp b/src/Algo/Render/topo3PrimalRender.cpp
index 22f26f6a735e6c281e1f180935acf27aebeef692..6397f96f78a4e62229d8eb3ecbf84f94095fa135 100644
--- a/src/Algo/Render/topo3PrimalRender.cpp
+++ b/src/Algo/Render/topo3PrimalRender.cpp
@@ -48,6 +48,7 @@ Topo3PrimalRender::Topo3PrimalRender():
 	m_topo_relation_width(3.0f),
 	m_color_save(NULL),
 	m_dartsColor(1.0f,1.0f,1.0f),
+	m_boundaryDartsColor(0.5f,0.5f,0.5f),
 	m_bufferDartPosition(NULL)
 {
 	m_vbo0 = new Utils::VBO();
@@ -127,7 +128,6 @@ void Topo3PrimalRender::setAllDartsColor(float r, float g, float b)
 		*colorDartBuf++ = b;
 	}
 	glUnmapBufferARB(GL_ARRAY_BUFFER);
-
 }
 
 void Topo3PrimalRender::setInitialDartsColor(float r, float g, float b)
@@ -135,6 +135,12 @@ void Topo3PrimalRender::setInitialDartsColor(float r, float g, float b)
 	m_dartsColor = Geom::Vec3f(r,g,b);
 }
 
+void Topo3PrimalRender::setInitialBoundaryDartsColor(float r, float g, float b)
+{
+	m_boundaryDartsColor = Geom::Vec3f(r,g,b);
+}
+
+
 void Topo3PrimalRender::drawDarts()
 {
 	if (m_nbDarts==0)