diff --git a/hub/city_model_structure/building.py b/hub/city_model_structure/building.py
index 65c3e417..e2a30906 100644
--- a/hub/city_model_structure/building.py
+++ b/hub/city_model_structure/building.py
@@ -447,9 +447,20 @@ class Building(CityObject):
     Identifies which building' walls adjoin the neighbouring building and saves that information in the
     corresponding surfaces
     """
-    for wall in self.walls:
-      percentage = 0
-      for building in self._neighbours:
-        for neighbour_wall in building.walls:
-          percentage += wall.shared_percentage(neighbour_wall)
-      wall.set_shared_percentage(percentage)
+    x = int((self.upper_corner[0] - self.lower_corner[0]) / 2)
+    y = int((self.upper_corner[1] - self.lower_corner[1]) / 2)
+    city_map = [['' for _ in range(y+1)] for _ in range(x+1)]
+    city_image = [[0 for _ in range(y+1)] for _ in range(x+1)]
+    for building_name in building_names:
+      building = city.city_object(building_name)
+      for ground in building.grounds:
+        length = len(ground.perimeter_polygon.coordinates) - 1
+        for i, coordinate in enumerate(ground.perimeter_polygon.coordinates):
+          j = i+1
+          if i == length:
+            j = 0
+          next_coordinate = ground.perimeter_polygon.coordinates[j]
+          point_1 = GeometryHelper.coordinate_to_map_point(coordinate, city)
+          point_2 = GeometryHelper.coordinate_to_map_point(next_coordinate, city)
+          for x in range(point_1.x, point_2.x):
+            y = GeometryHelper.point_between_point(point_1, point_2, x).y
diff --git a/hub/city_model_structure/building_demand/surface.py b/hub/city_model_structure/building_demand/surface.py
index 3a64bf2a..285393e3 100644
--- a/hub/city_model_structure/building_demand/surface.py
+++ b/hub/city_model_structure/building_demand/surface.py
@@ -336,12 +336,3 @@ class Surface:
     :param value: None or [ThermalBoundary]
     """
     self._associated_thermal_boundaries = value
-
-  def shared_percentage(self, neighbour_surface):
-    """
-    Calculate the percentage of a surface that is shared with a neighbour surface
-    :return: float
-    """
-    _shared_percentage = 0
-
-    return _shared_percentage
\ No newline at end of file
diff --git a/hub/city_model_structure/city_object.py b/hub/city_model_structure/city_object.py
index b5b84fcc..ab50250c 100644
--- a/hub/city_model_structure/city_object.py
+++ b/hub/city_model_structure/city_object.py
@@ -24,11 +24,15 @@ class CityObject:
     self._surfaces = surfaces
     self._type = None
     self._city_object_lower_corner = None
+    self._city_object_upper_corner = None
     self._detailed_polyhedron = None
     self._simplified_polyhedron = None
     self._min_x = ConfigurationHelper().max_coordinate
     self._min_y = ConfigurationHelper().max_coordinate
     self._min_z = ConfigurationHelper().max_coordinate
+    self._max_x = ConfigurationHelper().min_coordinate
+    self._max_y = ConfigurationHelper().min_coordinate
+    self._max_z = ConfigurationHelper().min_coordinate
     self._centroid = None
     self._external_temperature = dict()
     self._global_horizontal = dict()
@@ -212,6 +216,16 @@ class CityObject:
       self._city_object_lower_corner = [self._min_x, self._min_y, self._min_z]
     return self._city_object_lower_corner
 
+  @property
+  def upper_corner(self):
+    """
+    Get city object upper corner coordinates [x, y, z]
+    :return: [x,y,z]
+    """
+    if self._city_object_upper_corner is None:
+      self._city_object_upper_corner = [self._max_x, self._max_y, self._max_z]
+    return self._city_object_upper_corner
+
   @property
   def sensors(self) -> List[Sensor]:
     """
diff --git a/hub/helpers/geometry_helper.py b/hub/helpers/geometry_helper.py
index f2008fb4..9d691e11 100644
--- a/hub/helpers/geometry_helper.py
+++ b/hub/helpers/geometry_helper.py
@@ -14,6 +14,7 @@ from hub.city_model_structure.attributes.polygon import Polygon
 from hub.city_model_structure.attributes.polyhedron import Polyhedron
 from hub.helpers.location import Location
 
+
 class MapPoint:
   def __init__(self, x, y):
     self.x = int(x)
@@ -22,10 +23,12 @@ class MapPoint:
   def __str__(self):
     return f'({self.x}, {self.y})'
 
+
 class GeometryHelper:
   """
   Geometry helper class
   """
+  # todo: complete dictionary
   srs_transformations = {
     'urn:adv:crs:ETRS89_UTM32*DE_DHHN92_NH': 'epsg:25832'
   }
@@ -43,7 +46,7 @@ class GeometryHelper:
     m = (point_1.y - point_2.y)/(point_1.x - point_2.x)
     c = point_2.y - (m*point_2.x)
     y = (m*x)+c
-    return MapPoint(x,y)
+    return MapPoint(x, y)
 
   @staticmethod
   def city_mapping(city, building_names=None):