diff --git a/tutorial/tracking/model-based/generic/tutorial-mb-generic-tracker-read.cpp b/tutorial/tracking/model-based/generic/tutorial-mb-generic-tracker-read.cpp
index cadef0cee8..e9a66e94af 100755
--- a/tutorial/tracking/model-based/generic/tutorial-mb-generic-tracker-read.cpp
+++ b/tutorial/tracking/model-based/generic/tutorial-mb-generic-tracker-read.cpp
@@ -53,6 +53,10 @@ int main(int argc, char **argv)
   int nb_data = *arr_nb_data.data<int>();
   std::cout << "Number of images: " << nb_data << std::endl;
 
+  // Load all the poses
+  visp::cnpy::NpyArray arr_vec_poses = npz_data["vec_poses"];
+  double* vec_poses_ptr = arr_vec_poses.data<double>();
+
   for (int iter = 0; iter < nb_data; iter++) {
     std::string img_data_str = toString("png_image_%06d", iter);
      visp::cnpy::NpyArray arr_nb_data = npz_data[img_data_str];
@@ -81,10 +85,13 @@ int main(int argc, char **argv)
       }
     }
 
-    const std::string vec_pose_str = toString("vec_pose_%06d", iter);
-    visp::cnpy::NpyArray arr_vec_pose = npz_data[vec_pose_str];
-    vpHomogeneousMatrix cMo(vpTranslationVector(arr_vec_pose.data<double>()[3], arr_vec_pose.data<double>()[4], arr_vec_pose.data<double>()[5]),
-      vpThetaUVector(arr_vec_pose.data<double>()[0], arr_vec_pose.data<double>()[1], arr_vec_pose.data<double>()[2])
+    // const std::string vec_pose_str = toString("vec_pose_%06d", iter);
+    // visp::cnpy::NpyArray arr_vec_pose = npz_data[vec_pose_str];
+    // vpHomogeneousMatrix cMo(vpTranslationVector(arr_vec_pose.data<double>()[3], arr_vec_pose.data<double>()[4], arr_vec_pose.data<double>()[5]),
+    //   vpThetaUVector(arr_vec_pose.data<double>()[0], arr_vec_pose.data<double>()[1], arr_vec_pose.data<double>()[2])
+    // );
+    vpHomogeneousMatrix cMo(vpTranslationVector(vec_poses_ptr[6*iter + 3], vec_poses_ptr[6*iter + 4], vec_poses_ptr[6*iter + 5]),
+      vpThetaUVector(vec_poses_ptr[6*iter], vec_poses_ptr[6*iter + 1], vec_poses_ptr[6*iter + 2])
     );
     std::cout << "\ncMo:\n" << cMo << std::endl;
 
diff --git a/tutorial/tracking/model-based/generic/tutorial-mb-generic-tracker-save.cpp b/tutorial/tracking/model-based/generic/tutorial-mb-generic-tracker-save.cpp
index bc467362f5..470a10f757 100755
--- a/tutorial/tracking/model-based/generic/tutorial-mb-generic-tracker-save.cpp
+++ b/tutorial/tracking/model-based/generic/tutorial-mb-generic-tracker-save.cpp
@@ -75,8 +75,8 @@ int main(int argc, char **argv)
       << camera_name.c_str()[i] << " ; " << int(camera_name.c_str()[i]) << std::endl;
   }
 
-  visp::cnpy::npz_save(npz_filename, "camera_name", &vec_camera_name[0], { vec_camera_name.size() }, "a");
-  visp::cnpy::npz_save(npz_filename, "height", &height, { 1 }, "a");
+  visp::cnpy::npz_save(npz_filename, "camera_name", &vec_camera_name[0], { vec_camera_name.size() }, "w"); // overwrite
+  visp::cnpy::npz_save(npz_filename, "height", &height, { 1 }, "a"); // append
   visp::cnpy::npz_save(npz_filename, "width", &width, { 1 }, "a");
   visp::cnpy::npz_save(npz_filename, "channel", &channel, { 1 }, "a");
 
@@ -86,6 +86,9 @@ int main(int argc, char **argv)
   visp::cnpy::npz_save(npz_filename, "cam_u0", &cam_u0, { 1 }, "a");
   visp::cnpy::npz_save(npz_filename, "cam_v0", &cam_v0, { 1 }, "a");
 
+  std::vector<double> vec_poses;
+  vec_poses.reserve(g.getLastFrameIndex() * 6);
+
   int iter = 0;
   while (!g.end()) {
     g.acquire(I);
@@ -98,7 +101,9 @@ int main(int argc, char **argv)
     visp::cnpy::npz_save(npz_filename, toString("png_image_%06d", iter), &img_buffer[0], { (unsigned int) last_pos }, "a");
 
     std::vector<double> vec_pose = poseToVec(cMo);
-    visp::cnpy::npz_save(npz_filename, toString("vec_pose_%06d", iter), &vec_pose[0], { vec_pose.size() }, "a");
+    vec_poses.insert(vec_poses.end(), vec_pose.begin(), vec_pose.end());
+    // Commented, use instead a "multidimensional" array
+    // visp::cnpy::npz_save(npz_filename, toString("vec_pose_%06d", iter), &vec_pose[0], { vec_pose.size() }, "a");
 
     std::map<std::string, std::vector<std::vector<double> > > mapOfModels;
     std::map<std::string, unsigned int> mapOfW;
@@ -130,6 +135,9 @@ int main(int argc, char **argv)
     iter++;
   }
 
+  // Show how to save a "multidimensional" array
+  visp::cnpy::npz_save(npz_filename, "vec_poses", &vec_poses[0], { static_cast<size_t>(iter), 6 }, "a");
+
   visp::cnpy::npz_save(npz_filename, "nb_data", &iter, { 1 }, "a");
 
   return EXIT_SUCCESS;