diff --git a/Sampling-based Planning/rrt_2D/__pycache__/env.cpython-37.pyc b/Sampling-based Planning/rrt_2D/__pycache__/env.cpython-37.pyc
index d6169c0..c96512a 100644
Binary files a/Sampling-based Planning/rrt_2D/__pycache__/env.cpython-37.pyc and b/Sampling-based Planning/rrt_2D/__pycache__/env.cpython-37.pyc differ
diff --git a/Sampling-based Planning/rrt_2D/__pycache__/plotting.cpython-37.pyc b/Sampling-based Planning/rrt_2D/__pycache__/plotting.cpython-37.pyc
index d91e451..c6021a6 100644
Binary files a/Sampling-based Planning/rrt_2D/__pycache__/plotting.cpython-37.pyc and b/Sampling-based Planning/rrt_2D/__pycache__/plotting.cpython-37.pyc differ
diff --git a/Sampling-based Planning/rrt_2D/plotting.py b/Sampling-based Planning/rrt_2D/plotting.py
index f7fc975..f8a2129 100644
--- a/Sampling-based Planning/rrt_2D/plotting.py	
+++ b/Sampling-based Planning/rrt_2D/plotting.py	
@@ -3,10 +3,15 @@ Plotting tools for RRT_2D
 @author: huiming zhou
 """
 
-
 import matplotlib.pyplot as plt
 import matplotlib.patches as patches
 
+import os
+import sys
+
+sys.path.append(os.path.dirname(os.path.abspath(__file__)) +
+                "/../../Sampling-based Planning/")
+
 from rrt_2D import env
 
 
diff --git a/Sampling-based Planning/rrt_2D/rrt.py b/Sampling-based Planning/rrt_2D/rrt.py
index b8786d6..508b2a1 100644
--- a/Sampling-based Planning/rrt_2D/rrt.py	
+++ b/Sampling-based Planning/rrt_2D/rrt.py	
@@ -3,13 +3,17 @@ RRT_2D
 @author: huiming zhou
 """
 
+import math
+import numpy as np
+import os
+import sys
+
+sys.path.append(os.path.dirname(os.path.abspath(__file__)) +
+                "/../../Sampling-based Planning/")
 
 from rrt_2D import env
 from rrt_2D import plotting
 
-import numpy as np
-import math
-
 
 class Node:
     def __init__(self, n):
diff --git a/Sampling-based Planning/rrt_2D/rrt_star.py b/Sampling-based Planning/rrt_2D/rrt_star.py
index 394dd1c..58f7976 100644
--- a/Sampling-based Planning/rrt_2D/rrt_star.py	
+++ b/Sampling-based Planning/rrt_2D/rrt_star.py	
@@ -3,13 +3,17 @@ RRT_star 2D
 @author: huiming zhou
 """
 
+import math
+import numpy as np
+import os
+import sys
+
+sys.path.append(os.path.dirname(os.path.abspath(__file__)) +
+                "/../../Sampling-based Planning/")
 
 from rrt_2D import env
 from rrt_2D import plotting
 
-import numpy as np
-import math
-
 
 class Node:
     def __init__(self, n):