diff --git a/hub/city_model_structure/city_object.py b/hub/city_model_structure/city_object.py
index ab50250c..549a3362 100644
--- a/hub/city_model_structure/city_object.py
+++ b/hub/city_model_structure/city_object.py
@@ -34,6 +34,7 @@ class CityObject:
     self._max_y = ConfigurationHelper().min_coordinate
     self._max_z = ConfigurationHelper().min_coordinate
     self._centroid = None
+    self._volume = None
     self._external_temperature = dict()
     self._global_horizontal = dict()
     self._diffuse = dict()
@@ -63,7 +64,13 @@ class CityObject:
     Get city object volume in cubic meters
     :return: float
     """
-    return self.simplified_polyhedron.volume
+    if self._volume is None:
+      self._volume = self.simplified_polyhedron.volume
+    return self._volume
+
+  @volume.setter
+  def volume(self, value):
+    self._volume = value
 
   @property
   def detailed_polyhedron(self) -> Polyhedron:
diff --git a/hub/imports/geometry/geojson.py b/hub/imports/geometry/geojson.py
index 1adf95d1..f526bebd 100644
--- a/hub/imports/geometry/geojson.py
+++ b/hub/imports/geometry/geojson.py
@@ -6,6 +6,7 @@ Project Coder Guillermo Gutierrez Guillermo.GutierrezMorote@concordia.ca
 """
 import json
 
+import numpy as np
 import trimesh.creation
 
 from pyproj import Transformer
@@ -64,8 +65,10 @@ class Geojson:
     buildings = []
     for zone, surface_coordinates in enumerate(surfaces_coordinates):
       points = igh.points_from_string(igh.remove_last_point_from_string(surface_coordinates))
+      # geojson provides the roofs, need to be transform into grounds
+      points = igh.invert_points(points)
       polygon = Polygon(points)
-      surfaces.append(Surface(polygon, polygon, surface_type=cte.GROUND))
+      surfaces.append(Surface(polygon, polygon))
       buildings.append(Building(f'{name}_zone_{zone}', surfaces, year_of_construction, function))
     return buildings
 
@@ -74,22 +77,41 @@ class Geojson:
     lod0_buildings = Geojson._create_buildings_lod0(name, year_of_construction, function, surface_coordinates)
     surfaces = []
     buildings = []
+
     for zone, lod0_building in enumerate(lod0_buildings):
-      for surface in lod0_building.surfaces:
-        shapely_polygon = ShapelyPolygon(surface.solid_polygon.coordinates)
-        if not shapely_polygon.is_valid:
-          print(surface.solid_polygon.area)
-          print('error?', name, surface_coordinates)
-          continue
-        mesh = trimesh.creation.extrude_polygon(shapely_polygon, height)
-        for face in mesh.faces:
-          points = []
-          for vertex_index in face:
-            points.append(mesh.vertices[vertex_index])
-          polygon = Polygon(points)
-          surface = Surface(polygon, polygon)
-          surfaces.append(surface)
-        buildings.append(Building(f'{name}_zone_{zone}', surfaces, year_of_construction, function))
+      for surface in lod0_building.grounds:
+        volume = surface.solid_polygon.area * height
+        surfaces.append(surface)
+        roof_coordinates = []
+        # adding a roof means invert the polygon coordinates and change the Z value
+        for coordinate in surface.solid_polygon.coordinates:
+          roof_coordinate = np.array([coordinate[0], coordinate[1], height])
+          # insert the roof rotated already
+          roof_coordinates.insert(0, roof_coordinate)
+        polygon = Polygon(roof_coordinates)
+        roof = Surface(polygon, polygon)
+        surfaces.append(roof)
+        # adding a wall means add the point coordinates and the next point coordinates with Z's height and 0
+        coordinates_length = len(roof.solid_polygon.coordinates)
+        for i, coordinate in enumerate(roof.solid_polygon.coordinates):
+          j = i + 1
+          if j == coordinates_length:
+            j = 0
+          next_coordinate = roof.solid_polygon.coordinates[j]
+          wall_coordinates = [
+            np.array([coordinate[0], coordinate[1], 0.0]),
+            np.array([next_coordinate[0], next_coordinate[1], 0.0]),
+            np.array([next_coordinate[0], next_coordinate[1], next_coordinate[2]]),
+            np.array([coordinate[0], coordinate[1], coordinate[2]])
+          ]
+          polygon = Polygon(wall_coordinates)
+          wall = Surface(polygon, polygon)
+          surfaces.append(wall)
+
+        building = Building(f'{name}_zone_{zone}', surfaces, year_of_construction, function)
+        building.volume = volume
+        buildings.append(building)
+
     return buildings
 
   def _get_polygons(self, polygons, coordinates):
@@ -119,6 +141,8 @@ class Geojson:
 
   def _store_shared_percentage_to_walls(self, city, city_mapped):
     for building in city.buildings:
+      if building.name not in city_mapped.keys():
+        continue
       building_mapped = city_mapped[building.name]
       for wall in building.walls:
         percentage = 0
@@ -207,7 +231,7 @@ class Geojson:
         self._city.add_city_object(building)
       self._city.level_of_detail.geometry = lod
       if lod == 1:
-        lines_information = GeometryHelper.city_mapping(self._city)
+        lines_information = GeometryHelper.city_mapping(self._city, plot=True)
         self._store_shared_percentage_to_walls(self._city, lines_information)
       if len(missing_functions) > 0:
         print(f'There are unknown functions {missing_functions}')
diff --git a/hub/imports/geometry/helpers/geometry_helper.py b/hub/imports/geometry/helpers/geometry_helper.py
index b9384801..9c72d855 100644
--- a/hub/imports/geometry/helpers/geometry_helper.py
+++ b/hub/imports/geometry/helpers/geometry_helper.py
@@ -45,3 +45,10 @@ class GeometryHelper:
     array = points.split(' ')
     res = " "
     return res.join(array[0:len(array) - 3])
+
+  @staticmethod
+  def invert_points(points):
+    res = []
+    for point in points:
+      res.insert(0,point)
+    return res
diff --git a/hub/unittests/test_geometry_factory.py b/hub/unittests/test_geometry_factory.py
index 04c958e4..69860803 100644
--- a/hub/unittests/test_geometry_factory.py
+++ b/hub/unittests/test_geometry_factory.py
@@ -132,13 +132,14 @@ class TestGeometryFactory(TestCase):
     """
     Test geojson import
     """
-    file = 'neighbours.geojson'
+    file = 'concordia.geojson'
     city = self._get_city(file, 'geojson',
                           height_field='citygml_me',
                           year_of_construction_field='ANNEE_CONS',
                           function_field='CODE_UTILI')
 
-    hub.exports.exports_factory.ExportsFactory('obj', city, self._output_path).export()
+    for building in city.buildings:
+      print(building.volume)
     self.assertEqual(207, len(city.buildings), 'wrong number of buildings')
     self._check_buildings(city)
     for building in city.buildings:
@@ -150,13 +151,21 @@ class TestGeometryFactory(TestCase):
     Test neighbours map creation
     """
     file = 'neighbours.geojson'
+    city = self._get_city(file, 'geojson',
+                          year_of_construction_field='ANNEE_CONS',
+                          function_field='LIBELLE_UT')
+    info_lod0 = GeometryHelper.city_mapping(city, plot=False)
+
     city = self._get_city(file, 'geojson',
                           height_field='citygml_me',
                           year_of_construction_field='ANNEE_CONS',
                           function_field='LIBELLE_UT')
-    print(GeometryHelper.city_mapping(city, plot=True))
+    info_lod1 = GeometryHelper.city_mapping(city, plot=False)
+
+    self.assertEqual(info_lod0, info_lod1)
     for building in city.buildings:
       self.assertEqual(2, len(building.neighbours))
+      print(building.volume)
 
     self.assertEqual('2_part_0_zone_0',city.city_object('1_part_0_zone_0').neighbours[0].name)
     self.assertEqual('3_part_0_zone_0',city.city_object('1_part_0_zone_0').neighbours[1].name)
diff --git a/hub/unittests/tests_data/neighbours.geojson b/hub/unittests/tests_data/neighbours.geojson
index 65149ee9..437bf551 100644
--- a/hub/unittests/tests_data/neighbours.geojson
+++ b/hub/unittests/tests_data/neighbours.geojson
@@ -12,18 +12,18 @@
               -73.580414175680588,
               45.497641136608358
             ],
-            [
-              -73.581414175680588,
-              45.497641136608358
-            ],
-            [
-              -73.581414175680588,
-              45.498641136608358
-            ],
             [
               -73.580414175680588,
               45.498641136608358
             ],
+            [
+              -73.581414175680588,
+              45.498641136608358
+            ],
+            [
+              -73.581414175680588,
+              45.497641136608358
+            ],
             [
               -73.580414175680588,
               45.497641136608358
@@ -204,19 +204,20 @@
             [
               -73.581414175680588,
               45.497641136608358
+            ]
+            ,
+            [
+              -73.581414175680588,
+              45.498441136608358
+            ],
+            [
+              -73.582214175680588,
+              45.498441136608358
             ],
             [
               -73.582214175680588,
               45.497641136608358
             ],
-            [
-              -73.582214175680588,
-              45.498441136608358
-            ],
-            [
-              -73.581414175680588,
-              45.498441136608358
-            ],
             [
               -73.581414175680588,
               45.497641136608358
@@ -399,31 +400,30 @@
               -73.581914175680588,
               45.498441136608358
             ],
-            [
-              -73.581914175680588,
-              45.499641136608358
-            ],
-            [
-              -73.580914175680588,
-              45.499641136608358
-            ],
-            [
-              -73.580914175680588,
-              45.498641136608358
-            ],
-            [
-              -73.581414175680588,
-              45.498641136608358
-            ],
             [
               -73.581414175680588,
               45.498441136608358
             ],
+            [
+              -73.581414175680588,
+              45.498641136608358
+            ],
+            [
+              -73.580914175680588,
+              45.498641136608358
+            ],
+            [
+              -73.580914175680588,
+              45.499641136608358
+            ],
+            [
+              -73.581914175680588,
+              45.499641136608358
+            ],
             [
               -73.581914175680588,
               45.498441136608358
             ]
-
           ]
         ]
       },