diff --git a/server/gameserver/building.cc b/server/gameserver/building.cc
index 5876de0..00b7b16 100644
--- a/server/gameserver/building.cc
+++ b/server/gameserver/building.cc
@@ -66,3 +66,19 @@ void Building::FillMFObjectFull(cs::MFObjectFull* full_data)
 
     p->set_building_id(meta->i->_building_id());
 }
+
+ColliderComponent* Building::GetBoxBound()
+{
+    AabbCollider* collider = new AabbCollider();
+    collider->active = true;
+    collider->owner = this;
+    collider->_min = Vector2D(
+                             pos.x - meta->i->tilewidth()/2.0,
+                             pos.y - meta->i->tileheight()/2.0
+                             );
+    collider->_max = Vector2D(
+                              pos.x + meta->i->tilewidth()/2.0,
+                              pos.y + meta->i->tileheight()/2.0
+                              );
+    return collider;
+}
diff --git a/server/gameserver/building.h b/server/gameserver/building.h
index 1d046fa..ea976d0 100644
--- a/server/gameserver/building.h
+++ b/server/gameserver/building.h
@@ -24,5 +24,5 @@ class Building : public Entity
     void RecalcSelfCollider();
     virtual void FillMFObjectPart(cs::MFObjectPart* part_data) override;
     virtual void FillMFObjectFull(cs::MFObjectFull* full_data) override;
-
+    virtual ColliderComponent* GetBoxBound() override;
 };
diff --git a/server/gameserver/entity.cc b/server/gameserver/entity.cc
index 0d1c89a..3229dac 100644
--- a/server/gameserver/entity.cc
+++ b/server/gameserver/entity.cc
@@ -54,31 +54,6 @@ void Entity::FindLocationWithTarget(Entity* target)
     ColliderComponent* a_collider = GetBoxBound();
     Vector2D old_pos = pos;
     Vector2D new_pos = pos;
-    #if 0
-    {
-        std::vector<Entity*> objects;
-        room->BuildingBoxBoundCollisionDetection(this, objects);
-        if (objects.size() > 1) {
-            abort();
-        }
-        if (!objects.empty()) {
-            Building* building = (Building*)objects[0];
-            ColliderComponent* building_collider = building->GetBoxBound();
-            bool ret = a_collider->CalcSafePoint(building_collider, new_pos);
-            if (!ret) {
-                abort();
-            }
-            if (ret) {
-                pos = new_pos;
-                DestoryCollider(a_collider);
-                DestoryCollider(building_collider);
-                return;
-            } else {
-                DestoryCollider(building_collider);
-            }
-        }
-    }
-    #endif
     ColliderComponent* target_collider = target->GetBoxBound();
     {
         bool ret = a_collider->CalcSafePoint(target_collider, new_pos);
diff --git a/server/gameserver/entity.h b/server/gameserver/entity.h
index 73fad18..f5be628 100644
--- a/server/gameserver/entity.h
+++ b/server/gameserver/entity.h
@@ -12,11 +12,11 @@ enum EntityType_e
    ET_Player = 1,
    ET_Obstacle = 2,
    ET_Building = 3,
-   ET_LootSpawner = 4,
+   //ET_LootSpawner = 4,
    ET_Loot = 5,
-   ET_DeadBody = 6,
-   ET_Decal = 7,
-   ET_Projectile = 8,
+   //ET_DeadBody = 6,
+   //ET_Decal = 7,
+   //ET_Projectile = 8,
    ET_Smoke = 9,
 
    ET_Bullet = 20,
diff --git a/server/gameserver/human.cc b/server/gameserver/human.cc
index 957e30b..e118af0 100644
--- a/server/gameserver/human.cc
+++ b/server/gameserver/human.cc
@@ -110,6 +110,15 @@ void Human::FillMFObjectFull(cs::MFObjectFull* full_data)
     }
 }
 
+ColliderComponent* Human::GetBoxBound()
+{
+    CircleCollider* collider = new CircleCollider();
+    collider->owner = this;
+    collider->pos = pos;
+    collider->rad = GetRadius();
+    return collider;
+}
+
 void Human::FillMFPlayerStats(cs::MFPlayerStats* stats_pb)
 {
     stats_pb->set_player_id(entity_uniid);
diff --git a/server/gameserver/human.h b/server/gameserver/human.h
index 2e5a55d..c6b9df4 100644
--- a/server/gameserver/human.h
+++ b/server/gameserver/human.h
@@ -91,6 +91,7 @@ class Human : public Entity
     virtual float GetSpeed() override;
     virtual void FillMFObjectPart(cs::MFObjectPart* part_data) override;
     virtual void FillMFObjectFull(cs::MFObjectFull* full_data) override;
+    virtual ColliderComponent* GetBoxBound() override;
     virtual void FillMFPlayerStats(cs::MFPlayerStats* stats);
     void FillMFTeamData(cs::MFTeamData* team_data);
     void Shot(Vector2D& target_dir);
diff --git a/server/gameserver/loot.h b/server/gameserver/loot.h
index 00f2ae3..66e8a93 100644
--- a/server/gameserver/loot.h
+++ b/server/gameserver/loot.h
@@ -24,5 +24,4 @@ class Loot : public Entity
     void RecalcSelfCollider();
     virtual void FillMFObjectPart(cs::MFObjectPart* part_data) override;
     virtual void FillMFObjectFull(cs::MFObjectFull* full_data) override;
-
 };
diff --git a/server/gameserver/obstacle.cc b/server/gameserver/obstacle.cc
index c9f6ebf..9f81a4f 100644
--- a/server/gameserver/obstacle.cc
+++ b/server/gameserver/obstacle.cc
@@ -106,3 +106,18 @@ void Obstacle::FillMFObjectFull(cs::MFObjectFull* full_data)
         }
     }
 }
+
+ColliderComponent* Obstacle::GetBoxBound()
+{
+    if (self_collider_) {
+        CircleCollider* collider = new CircleCollider();
+        *collider = *self_collider_;
+        return collider;
+    }
+    if (self_collider2_) {
+        AabbCollider* collider = new AabbCollider();
+        *collider = *self_collider2_;
+        return collider;
+    }
+    return nullptr;
+}
diff --git a/server/gameserver/obstacle.h b/server/gameserver/obstacle.h
index 1b07e73..5b0e35b 100644
--- a/server/gameserver/obstacle.h
+++ b/server/gameserver/obstacle.h
@@ -41,7 +41,7 @@ class Obstacle : public Entity
     void RecalcSelfCollider();
     virtual void FillMFObjectPart(cs::MFObjectPart* part_data) override;
     virtual void FillMFObjectFull(cs::MFObjectFull* full_data) override;
-
+    virtual ColliderComponent* GetBoxBound() override;
 private:
     CircleCollider* self_collider_ = nullptr;
     AabbCollider* self_collider2_ = nullptr;
diff --git a/server/gameserver/room.cc b/server/gameserver/room.cc
index e199fb9..01164dd 100644
--- a/server/gameserver/room.cc
+++ b/server/gameserver/room.cc
@@ -365,6 +365,9 @@ void Room::CollisionDetection(Entity* sender, int detection_flags, std::vector<E
 {
     assert(uniid_hash_.size() < 1000);
     for (auto& pair : uniid_hash_) {
+        if (sender == pair.second) {
+            continue;
+        }
         if (a8::HasBitFlag(detection_flags, ET_Player) && pair.second->entity_type == ET_Player) {
             if (sender->entity_type == ET_Bullet) {
                 Bullet* bullet = (Bullet*)sender;
@@ -400,29 +403,19 @@ void Room::CollisionDetection(Entity* sender, int detection_flags, std::vector<E
     }
 }
 
-void Room::BuildingBoxBoundCollisionDetection(Human* hum, std::vector<Entity*>& objects)
+void Room::BuildingBoxBoundCollisionDetection(Entity* sender, std::vector<Entity*>& objects)
 {
+    ColliderComponent* a_collider = sender->GetBoxBound();
     for (auto& pair : uniid_hash_) {
         if (pair.second->entity_type == ET_Building) {
-            Building* building = (Building*)pair.second;
-            Vector2D a_min = Vector2D(
-                                      building->pos.x - building->meta->i->tilewidth()/2.0,
-                                      building->pos.y - building->meta->i->tileheight()/2.0
-                                      );
-            Vector2D a_max = Vector2D(
-                                      building->pos.x + building->meta->i->tilewidth()/2.0,
-                                      building->pos.y + building->meta->i->tileheight()/2.0
-                                      );
-            if (IntersectAabbCircle(
-                                    a_min,
-                                    a_max,
-                                    hum->pos,
-                                    hum->GetRadius()
-                                    )) {
+            ColliderComponent* target_collider = pair.second->GetBoxBound();
+            if (a_collider->Intersect(target_collider)) {
                 objects.push_back(pair.second);
             }
+            DestoryCollider(target_collider);
         }
     }
+    DestoryCollider(a_collider);
 }
 
 void Room::AddDeletedObject(unsigned short obj_uniid, bool soft_delete)
diff --git a/server/gameserver/room.h b/server/gameserver/room.h
index adb1176..c2c3747 100644
--- a/server/gameserver/room.h
+++ b/server/gameserver/room.h
@@ -53,7 +53,7 @@ public:
     Human* FindEnemy(Human* hum);
 
     void CollisionDetection(Entity* sender, int detection_flags, std::vector<Entity*>& objects);
-    void BuildingBoxBoundCollisionDetection(Human* hum, std::vector<Entity*>& objects);
+    void BuildingBoxBoundCollisionDetection(Entity* sender, std::vector<Entity*>& objects);
     void AddDeletedObject(unsigned short obj_uniid, bool soft_delete);
     void BeAddedObject(Entity* entity);