diff --git a/tutorials/Tutorial_303_Viewer_Qt/main_window.cpp b/tutorials/Tutorial_303_Viewer_Qt/main_window.cpp
index d262149..d6c010f 100644
--- a/tutorials/Tutorial_303_Viewer_Qt/main_window.cpp
+++ b/tutorials/Tutorial_303_Viewer_Qt/main_window.cpp
@@ -198,6 +198,38 @@ Model* MainWindow::open(const std::string& file_name) {
             std::cout << "mesh loaded. num faces: " << mesh->n_faces() << "; "
                 << "num vertices: " << mesh->n_vertices() << "; "
                 << "num edges: " << mesh->n_edges() << std::endl;
+#if 1
+            // Now let's create the drawable for the bounding box of the model.
+            // We also attached it to the model.
+            auto vertices = mesh->get_vertex_property<vec3>("v:point");
+            const auto& points = vertices.vector();
+            LinesDrawable* bbox_drawable = mesh->add_lines_drawable("bbox");
+            Box3 box;
+            // Compute the bounding box.
+            for (const auto& p : points)
+                box.add_point(p);
+            float xmin = box.min(0);   float xmax = box.max(0);
+            float ymin = box.min(1);   float ymax = box.max(1);
+            float zmin = box.min(2);   float zmax = box.max(2);
+            // The eight vertices of the bounding box.
+            const std::vector<vec3> bbox_points = {
+                vec3(xmin, ymin, zmax), vec3(xmax, ymin, zmax),
+                vec3(xmin, ymax, zmax),        vec3(xmax, ymax, zmax),
+                vec3(xmin, ymin, zmin),        vec3(xmax, ymin, zmin),
+                vec3(xmin, ymax, zmin),        vec3(xmax, ymax, zmin)
+            };
+            const std::vector<unsigned int> bbox_indices = {
+                0, 1, 2, 3, 4, 5, 6, 7,
+                0, 2, 4, 6, 1, 3, 5, 7,
+                0, 4, 2, 6, 1, 5, 3, 7
+            };
+
+            // Upload the vertex positions of the bounding box to the GPU.
+            bbox_drawable->update_vertex_buffer(bbox_points);
+            // Upload the vertex indices of the bounding box to the GPU.
+            bbox_drawable->update_index_buffer(bbox_indices);
+            bbox_drawable->set_default_color(vec3(1.0f, 0.0f, 0.0f));  // red color
+#endif
         }
     }
     else { // point cloud