diff --git a/src/opengeodeweb_back/routes/models/blueprint_models.py b/src/opengeodeweb_back/routes/models/blueprint_models.py
index f2c91b4a..cb5e7e49 100644
--- a/src/opengeodeweb_back/routes/models/blueprint_models.py
+++ b/src/opengeodeweb_back/routes/models/blueprint_models.py
@@ -25,14 +25,14 @@ def uuid_to_flat_index():
     )
 
     tree = ET.parse(vtm_file_path)
-    root = tree.getroot()
+    root = tree.find("vtkMultiBlockDataSet")
     uuid_to_flat_index = {}
     current_index = 1
 
     for elem in root.iter():
         if "uuid" in elem.attrib and elem.tag == "DataSet":
             uuid_to_flat_index[elem.attrib["uuid"]] = current_index
-            current_index += 1
+        current_index += 1
 
     return flask.make_response(
         {"uuid_to_flat_index": uuid_to_flat_index},
diff --git a/tests/test_models_routes.py b/tests/test_models_routes.py
index 1947999c..9160179e 100644
--- a/tests/test_models_routes.py
+++ b/tests/test_models_routes.py
@@ -4,27 +4,27 @@ def test_model_mesh_components(client):
     json = get_full_data()
     response = client.post(route, json=json)
     assert response.status_code == 200
+
     uuid_dict = response.json["uuid_to_flat_index"]
-    assert type(uuid_dict) is dict
+    assert isinstance(uuid_dict, dict)
 
     indices = list(uuid_dict.values())
     indices.sort()
-    assert indices[0] == 1
-    assert all(indices[i] == indices[i - 1] + 1 for i in range(1, len(indices)))
+    assert all(indices[i] > indices[i - 1] for i in range(1, len(indices)))
+    for uuid in uuid_dict.keys():
+        assert isinstance(uuid, str)
 
 
 def test_extract_brep_uuids(client):
     route = "/models/mesh_components"
     json_data = {"filename": "cube.og_brep", "geode_object": "BRep"}
-
     response = client.post(route, json=json_data)
 
     assert response.status_code == 200
     uuid_dict = response.json["uuid_dict"]
     assert isinstance(uuid_dict, dict)
-    assert (
-        "Block" in uuid_dict
-        or "Line" in uuid_dict
-        or "Surface" in uuid_dict
-        or "Corner" in uuid_dict
-    )
+    expected_keys = {"Block", "Line", "Surface", "Corner"}
+    assert any(key in uuid_dict for key in expected_keys)
+    for key, value in uuid_dict.items():
+        assert isinstance(value, list)
+        assert all(isinstance(v, str) for v in value)