diff --git a/server/gameserver/gridservice.cc b/server/gameserver/gridservice.cc
index b935319..0c6dd67 100644
--- a/server/gameserver/gridservice.cc
+++ b/server/gameserver/gridservice.cc
@@ -139,19 +139,38 @@ void GridService::MoveHuman(Human* hum)
     }
 }
 
-void GridService::AddEntity(Entity* entity, std::set<GridCell*>& inc_grid_list)
+void GridService::AddEntity(Entity* entity)
 {
-
+    int x = (int)entity->pos.x + cell_width_;
+    int y = (int)entity->pos.y + cell_width_;
+    if (BroderOverFlow(x, y)) {
+        abort();
+    }
+    entity->grid_id = x/cell_width_ + (y/cell_width_) * cell_count_per_row_;
+    if (entity->grid_id == 0 || entity->grid_id > max_grid_id_) {
+        abort();
+    }
+    cells_[entity->grid_id].entity_list.insert(entity);
 }
 
 bool GridService::HumanInGridList(Human* hum, std::set<GridCell*>& grid_list)
 {
-
+    for (auto& cell : grid_list) {
+        if (cell->human_list.find(hum) != cell->human_list.end()) {
+            return true;
+        }
+    }
+    return false;
 }
 
 bool GridService::EntityInGridList(Entity* entity, std::set<GridCell*>& grid_list)
 {
-
+    for (auto& cell : grid_list) {
+        if (cell->entity_list.find(entity) != cell->entity_list.end()) {
+            return true;
+        }
+    }
+    return false;
 }
 
 void GridService::GetGridList(int grid_id, int offset,
diff --git a/server/gameserver/gridservice.h b/server/gameserver/gridservice.h
index df7306f..a3c4033 100644
--- a/server/gameserver/gridservice.h
+++ b/server/gameserver/gridservice.h
@@ -37,7 +37,7 @@ class GridService
     void AddHuman(Human* hum);
     void MoveHuman(Human* hum);
 
-    void AddEntity(Entity* entity, std::set<GridCell*>& inc_grid_list);
+    void AddEntity(Entity* entity);
 
     bool HumanInGridList(Human* hum, std::set<GridCell*>& grid_list);
     bool EntityInGridList(Entity* entity, std::set<GridCell*>& grid_list);
diff --git a/server/gameserver/room.cc b/server/gameserver/room.cc
index 18a1244..5721ad5 100644
--- a/server/gameserver/room.cc
+++ b/server/gameserver/room.cc
@@ -403,10 +403,7 @@ void Room::CreateBuilding(int thing_id, float building_x, float building_y)
         building->pos = Vector2D(building_x, building_y);
         building->Initialize();
         uniid_hash_[building->entity_uniid] = building;
-        {
-            std::set<GridCell*> inc_grid_list;
-            grid_service.AddEntity(building, inc_grid_list);
-        }
+        grid_service.AddEntity(building);
         for (size_t door_idx = 0; door_idx < building_meta->doors.size(); ++door_idx) {
             if (door_idx >= 0 && door_idx < building->meta->doors.size()) {
                 MetaData::Building::Door* door_meta = &building->meta->doors[door_idx];
@@ -468,10 +465,7 @@ void Room::CreateLoot(int equip_id, Vector2D pos, int count)
         entity->count = count;
         entity->Initialize();
         uniid_hash_[entity->entity_uniid] = entity;
-        {
-            std::set<GridCell*> inc_grid_list;
-            grid_service.AddEntity(entity, inc_grid_list);
-        }
+        grid_service.AddEntity(entity);
     }
 }
 
@@ -953,10 +947,7 @@ Obstacle* Room::InternalCreateObstacle(int id, float x, float y,
             on_precreate(entity);
         }
         uniid_hash_[entity->entity_uniid] = entity;
-        {
-            std::set<GridCell*> inc_grid_list;
-            grid_service.AddEntity(entity, inc_grid_list);
-        }
+        grid_service.AddEntity(entity);
         return entity;
     }
     return nullptr;