diff --git a/include/gproshan/geometry/vec.h b/include/gproshan/geometry/vec.h
index 9083c3ae..922f742c 100644
--- a/include/gproshan/geometry/vec.h
+++ b/include/gproshan/geometry/vec.h
@@ -144,13 +144,13 @@ class vec
 			return res;
 		}
 
-		///< scalar division
+		///< element wise division & scalar division
 		__host_device__
-		vec<T, N> operator / (const T & a) const
+		vec<T, N> operator / (const vec<T, N> & v) const
 		{
 			vec<T, N> res;
 			for(index_t i = 0; i < N; ++i)
-				res[i] = values[i] / a;
+				res[i] = values[i] / v[i];
 			return res;
 		}
 
@@ -193,12 +193,12 @@ class vec
 			return *this;
 		}
 
-		///< scalar division self assign
+		///< element wise division self assign
 		__host_device__
-		const vec<T, N> & operator /= (const T & a)
+		const vec<T, N> & operator /= (const vec<T, N> & v)
 		{
-			for(T & v: values)
-				v /= a;
+			for(index_t i = 0; i < N; ++i)
+				values[i] /= v[i];
 			return *this;
 		}
 
@@ -263,6 +263,16 @@ vec<T, N> operator * (const T & a, const vec<T, N> & v)
 	return v * a;
 }
 
+///< scalar product
+template<class T, size_t N>
+__host_device__
+vec<T, N> operator / (const T & a, const vec<T, N> & v)
+{
+	vec<T, N> res;
+	for(index_t i = 0; i < N; ++i)
+		res[i] = a / v[i];
+	return res;
+}
 
 ///< cross product
 template<class T>
diff --git a/include/gproshan/mesh/che.h b/include/gproshan/mesh/che.h
index 4b8e3b78..5c524d54 100644
--- a/include/gproshan/mesh/che.h
+++ b/include/gproshan/mesh/che.h
@@ -40,7 +40,6 @@ class che
 
 			rgb_t() = default;
 			rgb_t(const vertex & v);
-			rgb_t(const float & fr, const float & fg, const float & fb);
 			rgb_t(const unsigned char & cr, const unsigned char & cg, const unsigned char & cb);
 			unsigned char & operator [] (const index_t & i);
 			operator vertex () const;
diff --git a/include/gproshan/raytracing/embree.h b/include/gproshan/raytracing/embree.h
index c1fe92c6..fa6c8f86 100644
--- a/include/gproshan/raytracing/embree.h
+++ b/include/gproshan/raytracing/embree.h
@@ -21,7 +21,7 @@ class embree : public raytracing
 		{
 			ray_hit(const vertex & p_org = {0, 0, 0},
 					const vertex & v_dir = {0, 0, 0},
-					float near = 0,
+					float near = 1e-5f,
 					float far = 1e20f);
 
 			vertex org() const;
diff --git a/include/gproshan/raytracing/utils.h b/include/gproshan/raytracing/utils.h
index cad89df9..93514412 100644
--- a/include/gproshan/raytracing/utils.h
+++ b/include/gproshan/raytracing/utils.h
@@ -78,13 +78,6 @@ struct t_eval_hit
 	__host_device__
 	t_eval_hit() {}
 
-	__host_device__
-	t_eval_hit(const CHE & pc, const index_t & aprimID)
-	{
-		primID = aprimID;
-		normal = pc.VN[primID];
-	}
-
 	__host_device__
 	t_eval_hit(const CHE & mesh, const index_t & aprimID, const T & au, const T & av, const scene_data & sc)
 	{
@@ -92,6 +85,15 @@ struct t_eval_hit
 		u = au;
 		v = av;
 
+		if(!mesh.n_trigs) // pointcloud
+		{
+			const che::rgb_t & c = mesh.VC[aprimID];
+			Kd = {T(c.r), T(c.g), T(c.b)};
+			Kd /= 255;
+			normal = mesh.VN[aprimID];
+			return;
+		}
+
 		const index_t he = primID * che::mtrig;
 
 		const index_t a = mesh.VT[he];
diff --git a/include/gproshan/util.h b/include/gproshan/util.h
index 9b088a50..64d31e0a 100644
--- a/include/gproshan/util.h
+++ b/include/gproshan/util.h
@@ -19,6 +19,9 @@ class partitions
 	index_t * sorted = nullptr;
 
 	public:
+		partitions(index_t * s = nullptr);
+		void add(const index_t & size);
+		size_t size(const index_t & i) const;
 		part operator () (const index_t & i) const;
 };
 
diff --git a/include/gproshan/viewer/viewer.h b/include/gproshan/viewer/viewer.h
index fd7a9200..3e3acc4e 100644
--- a/include/gproshan/viewer/viewer.h
+++ b/include/gproshan/viewer/viewer.h
@@ -137,6 +137,7 @@ class viewer
 
 		static bool m_help(viewer * view);
 		static bool m_close(viewer * view);
+		static bool m_maximize(viewer * view);
 		static bool m_hide_show_imgui(viewer * view);
 
 		static bool m_save_load_view(viewer * view);
diff --git a/src/gproshan/mesh/che.cpp b/src/gproshan/mesh/che.cpp
index 1d206688..e6e9d325 100644
--- a/src/gproshan/mesh/che.cpp
+++ b/src/gproshan/mesh/che.cpp
@@ -27,13 +27,11 @@ size_t & che::rw(const size_t & n)
 }
 
 
-che::rgb_t::rgb_t(const vertex & v): rgb_t(v.x(), v.y(), v.z()) {}
-
-che::rgb_t::rgb_t(const float & fr, const float & fg, const float & fb)
+che::rgb_t::rgb_t(const vertex & v)
 {
-	r = (unsigned char) (fr * 255);
-	g = (unsigned char) (fg * 255);
-	b = (unsigned char) (fb * 255);
+	r = (unsigned char) (v.x() * 255);
+	g = (unsigned char) (v.y() * 255);
+	b = (unsigned char) (v.z() * 255);
 }
 
 che::rgb_t::rgb_t(const unsigned char & cr, const unsigned char & cg, const unsigned char & cb): r(cr), g(cg), b(cb) {}
diff --git a/src/gproshan/mesh/che_ply.cpp b/src/gproshan/mesh/che_ply.cpp
index 01a7ef4e..29afb253 100644
--- a/src/gproshan/mesh/che_ply.cpp
+++ b/src/gproshan/mesh/che_ply.cpp
@@ -266,6 +266,9 @@ void che_ply::write_file(const che * mesh, const std::string & file, const bool
 	fprintf(fp, "property %s x\n", type);
 	fprintf(fp, "property %s y\n", type);
 	fprintf(fp, "property %s z\n", type);
+	fprintf(fp, "property %s nx\n", type);
+	fprintf(fp, "property %s ny\n", type);
+	fprintf(fp, "property %s nz\n", type);
 	if(color)
 	{
 		fprintf(fp, "property uchar red\n");
@@ -276,15 +279,12 @@ void che_ply::write_file(const che * mesh, const std::string & file, const bool
 	fprintf(fp, "property list uchar uint vertex_index\n");
 	fprintf(fp, "end_header\n");
 
-	if(color)
+	for(index_t v = 0; v < mesh->n_vertices; ++v)
 	{
-		for(index_t v = 0; v < mesh->n_vertices; ++v)
-		{
-			fwrite(&mesh->point(v), sizeof(vertex), 1, fp);
-			fwrite(&mesh->rgb(v), sizeof(rgb_t), 1, fp);
-		}
+		fwrite(&mesh->point(v), sizeof(vertex), 1, fp);
+		fwrite(&mesh->normal(v), sizeof(vertex), 1, fp);
+		if(color) fwrite(&mesh->rgb(v), sizeof(rgb_t), 1, fp);
 	}
-	else fwrite(&mesh->point(0), sizeof(vertex), mesh->n_vertices, fp);
 
 	unsigned char mtrig = che::mtrig;
 	for(index_t he = 0; he < mesh->n_half_edges; he += che::mtrig)
diff --git a/src/gproshan/raytracing/embree.cpp b/src/gproshan/raytracing/embree.cpp
index 7f35e9e7..f0b25a7a 100644
--- a/src/gproshan/raytracing/embree.cpp
+++ b/src/gproshan/raytracing/embree.cpp
@@ -253,9 +253,7 @@ vec3 embree::closesthit_radiance(const vertex & org, const vertex & dir, const l
 
 	const CHE * mesh = g_meshes[r.hit.geomID];
 
-	eval_hit hit;
-	if(mesh->n_trigs)
-		hit = {*mesh, r.hit.primID, r.hit.u, r.hit.v, sc};
+	eval_hit hit(*mesh, r.hit.primID, r.hit.u, r.hit.v, sc);
 	hit.position = r.pos();
 	hit.normal = flat ? r.normal() : hit.normal;
 
diff --git a/src/gproshan/raytracing/optix.cu b/src/gproshan/raytracing/optix.cu
index b42dabec..de3c95e4 100644
--- a/src/gproshan/raytracing/optix.cu
+++ b/src/gproshan/raytracing/optix.cu
@@ -121,7 +121,7 @@ extern "C" __global__ void __raygen__render_frame()
 	optixTrace(	optix_params.traversable,
 				* (float3 *) &optix_params.cam_pos,
 				* (float3 *) &ray_dir,
-				0.f,	// tmin
+				1e-5f,	// tmin
 				1e20f,	// tmax
 				0.0f,	// rayTime
 				OptixVisibilityMask(255),
diff --git a/src/gproshan/scenes/scanner.cpp b/src/gproshan/scenes/scanner.cpp
index 8057a52e..5da52172 100644
--- a/src/gproshan/scenes/scanner.cpp
+++ b/src/gproshan/scenes/scanner.cpp
@@ -40,10 +40,20 @@ che * scanner_ptx(const rt::raytracing * rt, const size_t & n_rows, const size_t
 
 		mesh_ptx->point(v) = h.position;
 		mesh_ptx->normal(v) = h.normal;
-		mesh_ptx->heatmap(v) = h.dist / M_SQRT2;
+		mesh_ptx->heatmap(v) = h.dist;
 		mesh_ptx->rgb(v) = h.Kd;
 	}
 
+	real_t max_dist = 0;
+
+	#pragma omp parallel for reduction(std::max: max_dist)
+	for(index_t v = 0; v < mesh_ptx->n_vertices; ++v)
+		max_dist = std::max(max_dist, mesh_ptx->heatmap(v));
+
+	#pragma omp parallel for
+	for(index_t v = 0; v < mesh_ptx->n_vertices; ++v)
+		mesh_ptx->heatmap(v) /= max_dist;
+
 	return mesh_ptx;
 }
 
diff --git a/src/gproshan/util.cpp b/src/gproshan/util.cpp
index b81b31a7..2d736bc4 100644
--- a/src/gproshan/util.cpp
+++ b/src/gproshan/util.cpp
@@ -7,10 +7,25 @@
 namespace gproshan {
 
 
+partitions::partitions(index_t * s): sorted(s)
+{
+	splits.push_back(0);
+}
+
+void partitions::add(const index_t & size)
+{
+	return splits.push_back(size + splits.back());
+}
+
+size_t partitions::size(const index_t & i) const
+{
+	return splits[i + 1] - splits[i];
+}
+
 partitions::part partitions::operator () (const index_t & i) const
 {
 	assert(i > 0 && i < splits.size());
-	return {splits[i - 1], splits[i], sorted};
+	return {splits[i], splits[i + 1], sorted};
 }
 
 
diff --git a/src/gproshan/viewer/viewer.cpp b/src/gproshan/viewer/viewer.cpp
index 04a27523..6dde08da 100644
--- a/src/gproshan/viewer/viewer.cpp
+++ b/src/gproshan/viewer/viewer.cpp
@@ -398,6 +398,7 @@ void viewer::init_menus()
 	sub_menus.push_back("Viewer");
 	add_process(GLFW_KEY_F1, "F1", "Help", m_help);
 	add_process(GLFW_KEY_ESCAPE, "ESCAPE", "Close", m_close);
+	add_process(GLFW_KEY_F11, "F11", "Maximize", m_maximize);
 	add_process(GLFW_KEY_I, "F1", "Hide/Show ImGui", m_hide_show_imgui);
 	add_process(GLFW_KEY_PERIOD, "PERIOD", "Save/Load view", m_save_load_view);
 	add_process(GLFW_KEY_UP, "UP", "Zoom in", m_zoom_in);
@@ -650,6 +651,12 @@ bool viewer::m_close(viewer * view)
 	return false;
 }
 
+bool viewer::m_maximize(viewer * view)
+{
+	glfwMaximizeWindow(view->window);
+	return false;
+}
+
 bool viewer::m_hide_show_imgui(viewer * view)
 {
 	view->hide_imgui = !view->hide_imgui;