diff --git a/AABB_tree/demo/AABB_tree/CMakeLists.txt b/AABB_tree/demo/AABB_tree/CMakeLists.txt
index 99a1a0182e7..89051f55496 100644
--- a/AABB_tree/demo/AABB_tree/CMakeLists.txt
+++ b/AABB_tree/demo/AABB_tree/CMakeLists.txt
@@ -52,9 +52,6 @@ if(CGAL_Qt4_FOUND AND QT4_FOUND AND OPENGL_FOUND AND QGLVIEWER_FOUND)
   qt4_generate_moc( "${CMAKE_CURRENT_SOURCE_DIR}/Viewer.h" Viewer_moc.cpp )
   add_file_dependencies( Viewer_moc.cpp "${CMAKE_CURRENT_SOURCE_DIR}/Viewer.h" )
 
-  qt4_generate_moc( "${CMAKE_CURRENT_SOURCE_DIR}/Scene.h" Scene_moc.cpp )
-  add_file_dependencies( Scene_moc.cpp "${CMAKE_CURRENT_SOURCE_DIR}/Scene.h" )
-
   qt4_add_resources ( RESOURCE_FILES AABB_demo.qrc )
 
     add_file_dependencies( AABB_demo.cpp "${CMAKE_CURRENT_BINARY_DIR}/MainWindow_moc.cpp"
diff --git a/AABB_tree/demo/AABB_tree/Color_ramp.h b/AABB_tree/demo/AABB_tree/Color_ramp.h
index d4c4d2fd79d..f28dd5c13f7 100644
--- a/AABB_tree/demo/AABB_tree/Color_ramp.h
+++ b/AABB_tree/demo/AABB_tree/Color_ramp.h
@@ -88,6 +88,27 @@ public:
     rebuild();
   }
 
+  void build_red()
+  {
+    reset();
+    m_colors[3][0] = 1;m_colors[0][0] = 128;m_colors[1][0] = 0;m_colors[2][0] = 0;
+    m_colors[3][80] = 1;m_colors[0][80] = 255;m_colors[1][80] = 0;m_colors[2][80] = 0;
+    m_colors[3][160] = 1;m_colors[0][160] = 255;m_colors[1][160] = 128;m_colors[2][160] = 0;
+    m_colors[3][255] = 1;m_colors[0][255] = 255;m_colors[1][255] = 255;m_colors[2][255] = 255;
+    rebuild();
+  }
+
+  void build_blue()
+  {
+    reset();
+    m_colors[3][0] = 1;m_colors[0][0] = 0;m_colors[1][0] = 0;m_colors[2][0] = 128;
+    m_colors[3][80] = 1;m_colors[0][80] = 0;m_colors[1][80] = 0;m_colors[2][80] = 255;
+    m_colors[3][160] = 1;m_colors[0][160] = 0;m_colors[1][160] = 255;m_colors[2][160] = 255;
+    m_colors[3][255] = 1;m_colors[0][255] = 255;m_colors[1][255] = 255;m_colors[2][255] = 255;
+    rebuild();
+  }
+
+
   void build_fire()
   {
     reset();
diff --git a/AABB_tree/demo/AABB_tree/Scene.cpp b/AABB_tree/demo/AABB_tree/Scene.cpp
index c4afdc7099b..7209691fe8a 100644
--- a/AABB_tree/demo/AABB_tree/Scene.cpp
+++ b/AABB_tree/demo/AABB_tree/Scene.cpp
@@ -30,6 +30,9 @@ Scene::Scene()
 	// distance functions
 	m_max_distance_function = (FT)0.0;
 	m_signed_distance_function = false;
+
+	m_red_ramp.build_red();
+	m_blue_ramp.build_blue();
 }
 
 Scene::~Scene()
@@ -175,13 +178,13 @@ void Scene::draw_unsigned_distance_function()
 			unsigned int i01 = 255-(unsigned int)(255.0 * d01 / m_max_distance_function);
 			unsigned int i11 = 255-(unsigned int)(255.0 * d11 / m_max_distance_function);
 			unsigned int i10 = 255-(unsigned int)(255.0 * d10 / m_max_distance_function);
-			::glColor3ub(m_ramp.r(i00),m_ramp.g(i00),m_ramp.b(i00));
+			::glColor3ub(m_thermal_ramp.r(i00),m_thermal_ramp.g(i00),m_thermal_ramp.b(i00));
 			::glVertex3d(p00.x(),p00.y(),p00.z());
-			::glColor3ub(m_ramp.r(i01),m_ramp.g(i01),m_ramp.b(i01));
+			::glColor3ub(m_thermal_ramp.r(i01),m_thermal_ramp.g(i01),m_thermal_ramp.b(i01));
 			::glVertex3d(p01.x(),p01.y(),p01.z());
-			::glColor3ub(m_ramp.r(i11),m_ramp.g(i11),m_ramp.b(i11));
+			::glColor3ub(m_thermal_ramp.r(i11),m_thermal_ramp.g(i11),m_thermal_ramp.b(i11));
 			::glVertex3d(p11.x(),p11.y(),p11.z());
-			::glColor3ub(m_ramp.r(i10),m_ramp.g(i10),m_ramp.b(i10));
+			::glColor3ub(m_thermal_ramp.r(i10),m_thermal_ramp.g(i10),m_thermal_ramp.b(i10));
 			::glVertex3d(p10.x(),p10.y(),p10.z());
 		}
 		::glEnd();
@@ -214,32 +217,34 @@ void Scene::draw_signed_distance_function()
 			FT& d10 = pd10.second;
 
 			// determines grey level
-			double g00 = (double)std::fabs(d00) / m_max_distance_function;
-			double g01 = (double)std::fabs(d01) / m_max_distance_function;
-			double g11 = (double)std::fabs(d11) / m_max_distance_function;
-			double g10 = (double)std::fabs(d10) / m_max_distance_function;
-
-			// determines color (red vs blue for inside vs outside)
-			double r00 = d00 < 0.0 ?  g00 : 0.0;
-			double b00 = d00 > 0.0 ?  g00 : 0.0;
-
-			double r01 = d01 < 0.0 ?  g01 : 0.0;
-			double b01 = d01 > 0.0 ?  g01 : 0.0;
-
-			double r11 = d11 < 0.0 ?  g11 : 0.0;
-			double b11 = d11 > 0.0 ?  g11 : 0.0;
-
-			double r10 = d10 < 0.0 ?  g10 : 0.0;
-			double b10 = d10 > 0.0 ?  g10 : 0.0;
+			unsigned int i00 = 255-(unsigned)(255.0 * (double)std::fabs(d00) / m_max_distance_function);
+			unsigned int i01 = 255-(unsigned)(255.0 * (double)std::fabs(d01) / m_max_distance_function);
+			unsigned int i11 = 255-(unsigned)(255.0 * (double)std::fabs(d11) / m_max_distance_function);
+			unsigned int i10 = 255-(unsigned)(255.0 * (double)std::fabs(d10) / m_max_distance_function);
 
 			// assembles one quad
-			::glColor3d(r00,0.0,b00);
+			if(d00 > 0.0)
+				::glColor3ub(m_red_ramp.r(i00),m_red_ramp.g(i00),m_red_ramp.b(i00));
+			else
+				::glColor3ub(m_blue_ramp.r(i00),m_blue_ramp.g(i00),m_blue_ramp.b(i00));
 			::glVertex3d(p00.x(),p00.y(),p00.z());
-			::glColor3d(r01,0.0,b01);
+
+			if(d01 > 0.0)
+				::glColor3ub(m_red_ramp.r(i01),m_red_ramp.g(i01),m_red_ramp.b(i01));
+			else
+				::glColor3ub(m_blue_ramp.r(i01),m_blue_ramp.g(i01),m_blue_ramp.b(i01));
 			::glVertex3d(p01.x(),p01.y(),p01.z());
-			::glColor3d(r11,0.0,b11);
+
+			if(d11 > 0)
+				::glColor3ub(m_red_ramp.r(i11),m_red_ramp.g(i11),m_red_ramp.b(i11));
+			else
+				::glColor3ub(m_blue_ramp.r(i11),m_blue_ramp.g(i11),m_blue_ramp.b(i11));
 			::glVertex3d(p11.x(),p11.y(),p11.z());
-			::glColor3d(r10,0.0,b10);
+
+			if(d10 > 0)
+				::glColor3ub(m_red_ramp.r(i10),m_red_ramp.g(i10),m_red_ramp.b(i10));
+			else
+				::glColor3ub(m_blue_ramp.r(i10),m_blue_ramp.g(i10),m_blue_ramp.b(i10));
 			::glVertex3d(p10.x(),p10.y(),p10.z());
 		}
 		::glEnd();
@@ -429,9 +434,9 @@ void Scene::benchmark_distances()
 	tree.accelerate_distance_queries();
 	std::cout << "done (" << time.elapsed() << " ms)" << std::endl;
 
-	// (cache experiments)
-	std::cout << "First call to populate the cache:" << std::endl;
-	bench_closest_point(tree);
+	// TODO: check what the KD-tree is doing in there for large models.
+	std::cout << "One single call to initialize KD-tree" << std::endl;
+	tree.closest_point(CGAL::ORIGIN);
 
 	std::cout << "------- Now, the real benchmark -------" << std::endl;
 	bench_closest_point(tree);
diff --git a/AABB_tree/demo/AABB_tree/Scene.h b/AABB_tree/demo/AABB_tree/Scene.h
index 3fec7f0a375..f89d6a285cd 100644
--- a/AABB_tree/demo/AABB_tree/Scene.h
+++ b/AABB_tree/demo/AABB_tree/Scene.h
@@ -71,7 +71,9 @@ private:
   bool m_signed_distance_function;
   typedef std::pair<Point,FT> Point_distance;
   Point_distance m_distance_function[100][100];
-  Color_ramp m_ramp;
+  Color_ramp m_thermal_ramp;
+  Color_ramp m_red_ramp;
+  Color_ramp m_blue_ramp;
   
   // view options
   bool m_view_points;
diff --git a/AABB_tree/doc_tex/AABB_tree/performances.tex b/AABB_tree/doc_tex/AABB_tree/performances.tex
index 3b5d623453e..103d59f7f96 100644
--- a/AABB_tree/doc_tex/AABB_tree/performances.tex
+++ b/AABB_tree/doc_tex/AABB_tree/performances.tex
@@ -63,11 +63,8 @@ The surface triangle mesh chosen for benchmarking distances is again the knot mo
    14,400 &   157 & 31,472 & 33,529 & 34,817 \\
    57,600 &   330 & 15,602 & 16,355 & 17,106 \\
   230,400 & 1,203 &  6,528 &  8,287 &  8,683 \\
-  921,600 & 5,047 &    563 &  4,221 &  4,424 \\
+  921,600 & 5,047 &  4,399 &  4,221 &  4,424 \\
   \hline
 \end{tabular}
 
-% TOFIX: understand why we mesure 563 above (measure is repeatable).
-
-