diff --git a/src/notebooks/reader.ipynb b/src/notebooks/reader.ipynb
index e4bdda2..a40f923 100644
--- a/src/notebooks/reader.ipynb
+++ b/src/notebooks/reader.ipynb
@@ -31,7 +31,7 @@
     "\n",
     "# Setup the reader\n",
     "# We suppose that the necessary files are in the same directory as the notebook\n",
-    "case_file = \"strasbourg_sm_lod1/City_Energy_Modeling.case\"\n",
+    "case_file = \"strasbourg_sm_lod1/exports/City_Energy_Modeling.case\"\n",
     "# Setup the reader\n",
     "reader = vtk.vtkEnSightGoldBinaryReader()\n",
     "reader.SetCaseFileName(case_file)\n",
@@ -57,6 +57,59 @@
     "print(\"Number of scalar points?: \", reader.GetOutput().GetBlock(0).GetCellData().GetArray(\"solar_shading_coeff\").GetNumberOfTuples())"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "837d2acc",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import numpy as np"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "dd8125e0",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "id_reader = vtk.vtkEnSightGoldBinaryReader()\n",
+    "id_reader.SetCaseFileName(\"strasbourg_sm_lod1/export_ids/City_Energy_Modeling.case\")\n",
+    "id_reader.ReadAllVariablesOn()\n",
+    "id_reader.Update()\n",
+    "\n",
+    "id_reader.SetTimeValue(id_reader.GetTimeSets().GetItem(0).GetValue(0))\n",
+    "id_reader.Update()\n",
+    "output = id_reader.GetOutput().GetBlock(0)\n",
+    "cell_data = output.GetCellData()\n",
+    "building_ids = cell_data.GetArray(\"building_id\")\n",
+    "building_element_ids = cell_data.GetArray(\"building_element_id\")\n",
+    "\n",
+    "bids = []\n",
+    "beids = []\n",
+    "\n",
+    "for i in range(output.GetNumberOfCells()):\n",
+    "    bid_part1, bid_part2, bid_part3 = building_ids.GetTuple(i)\n",
+    "    bid_part1 = np.int64(bid_part1)\n",
+    "    bid_part2 = np.int64(bid_part2) << 22\n",
+    "    bid_part3 = np.int64(bid_part3) << 44\n",
+    "    bids.append(bid_part1+bid_part2+bid_part3)\n",
+    "\n",
+    "    beids.append(int(building_element_ids.GetTuple(i)[0]))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "4520ecd8",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "print(f\"# Building IDs : {np.unique(bids).shape[0]}\")\n",
+    "print(f\"# Unique building face ids : {np.unique(beids).shape[0]} -- from  {min(beids)} to {max(beids)}\")"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "15d2113f",
@@ -122,9 +175,27 @@
     "    gis = json.load(f)\n",
     "\n",
     "reference_coordinates = gis[\"referenceCoordinates\"]\n",
-    "print(\"Reference coordinates: \", reference_coordinates)\n",
-    "\n",
-    "del gis"
+    "print(\"Reference coordinates: \", reference_coordinates)\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "2c4ef203",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "true_ids = np.array([building[\"id\"] for building in gis[\"building\"]])"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "1452221e",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "len(np.setdiff1d(np.unique(bids),true_ids)), len(np.setdiff1d(true_ids,np.unique(bids)))"
    ]
   },
   {