diff --git a/server/gameserver/mapinstance.cc b/server/gameserver/mapinstance.cc
index 6a46b1cd..cae6fa1f 100644
--- a/server/gameserver/mapinstance.cc
+++ b/server/gameserver/mapinstance.cc
@@ -882,5 +882,5 @@ bool MapInstance::SceneRaycast(const glm::vec3& orig,
                                float max_distance,
                                glm::vec3& hit_pos)
 {
-
+    int raycast_index = MapMgr::Instance()->IncCurrRaycastIndex();
 }
diff --git a/server/gameserver/mapmgr.cc b/server/gameserver/mapmgr.cc
index c10c144d..55389a13 100644
--- a/server/gameserver/mapmgr.cc
+++ b/server/gameserver/mapmgr.cc
@@ -23,6 +23,7 @@ void MapMgr::Init()
              map_instance->map_id = map_meta->map_id();
              map_instance->Init();
              instance_hash_[map_instance->map_id] = map_instance;
+             instance_list_.push_back(map_instance);
              {
                  auto itr = mode_hash_.find(map_meta->map_mode());
                  if (itr != mode_hash_.end()) {
diff --git a/server/gameserver/mapmgr.h b/server/gameserver/mapmgr.h
index dbdcd12a..439f5c8a 100644
--- a/server/gameserver/mapmgr.h
+++ b/server/gameserver/mapmgr.h
@@ -17,11 +17,14 @@ public:
 
     void AttachRoom(Room* room, RoomInitInfo& init_info);
     std::shared_ptr<MapInstance> GetMapInstance(int map_id);
+    int IncCurrRaycastIndex() { return ++curr_raycast_index_; };
 
 private:
     std::shared_ptr<MapInstance> RandMapInstance(int map_mode);
 
 private:
+    int curr_raycast_index_ = 1000;
+    std::vector<std::shared_ptr<MapInstance>> instance_list_;
     std::map<int, std::shared_ptr<MapInstance>> instance_hash_;
     std::map<int, std::vector<std::shared_ptr<MapInstance>>> mode_hash_;
 };