diff --git a/gym_art/quadrotor_multi/quad_scenarios.py b/gym_art/quadrotor_multi/quad_scenarios.py
index 9f9eb59..b955f9e 100644
--- a/gym_art/quadrotor_multi/quad_scenarios.py
+++ b/gym_art/quadrotor_multi/quad_scenarios.py
@@ -4,7 +4,7 @@ import copy
 
 from gym_art.quadrotor_multi.quad_scenarios_utils import QUADS_PARAMS_DICT, update_formation_and_max_agent_per_layer, \
     update_layer_dist, get_formation_range, get_goal_by_formation, get_z_value, QUADS_MODE_LIST, \
-    QUADS_MODE_LIST_OBSTACLES
+    QUADS_MODE_LIST_OBSTACLES, QUADS_MODE_LIST_SIMPLE
 from gym_art.quadrotor_multi.quad_utils import generate_points, get_grid_dim_number
 
 
@@ -623,7 +623,9 @@ class Scenario_mix(QuadrotorScenario):
         # Once change the parameter here, should also update QUADS_PARAMS_DICT to make sure it is same as run a single scenario
         # key: quads_mode
         # value: 0. formation, 1: [formation_low_size, formation_high_size], 2: episode_time
-        if obst_mode == 'no_obstacles':
+        if num_agents == 1:
+            self.quads_mode_list = QUADS_MODE_LIST_SIMPLE
+        elif obst_mode == 'no_obstacles':
             self.quads_mode_list = QUADS_MODE_LIST
         else:
             self.quads_mode_list = QUADS_MODE_LIST_OBSTACLES
diff --git a/gym_art/quadrotor_multi/quad_utils.py b/gym_art/quadrotor_multi/quad_utils.py
index d56c5d5..a8792fc 100644
--- a/gym_art/quadrotor_multi/quad_utils.py
+++ b/gym_art/quadrotor_multi/quad_utils.py
@@ -208,7 +208,7 @@ def points_in_sphere(n, x):
 
 def generate_points(n=3):
     if n < 3:
-        print("The number of goals can not smaller than 3, The system has cast it to 3")
+        # print("The number of goals can not smaller than 3, The system has cast it to 3")
         n = 3
     return points_in_sphere(n, 0.1 + 1.2 * n)