diff --git a/Sampling-based Planning/.idea/dictionaries/zhou.xml b/Sampling-based Planning/.idea/dictionaries/zhou.xml
new file mode 100644
index 0000000..6638eb0
--- /dev/null
+++ b/Sampling-based Planning/.idea/dictionaries/zhou.xml	
@@ -0,0 +1,8 @@
+<component name="ProjectDictionaryState">
+  <dictionary name="zhou">
+    <words>
+      <w>huiming</w>
+      <w>zhou</w>
+    </words>
+  </dictionary>
+</component>
\ No newline at end of file
diff --git a/Sampling-based Planning/rrt_2D/env.py b/Sampling-based Planning/rrt_2D/env.py
index b8b8e0d..5810f28 100644
--- a/Sampling-based Planning/rrt_2D/env.py	
+++ b/Sampling-based Planning/rrt_2D/env.py	
@@ -1,3 +1,9 @@
+"""
+Environment for rrt_2D
+@author: huiming zhou
+"""
+
+
 class Env:
     def __init__(self):
         self.x_range = (0, 50)
@@ -42,4 +48,4 @@ class Env:
             (45, 20, 2)
         ]
 
-        return obs_cir
\ No newline at end of file
+        return obs_cir
diff --git a/Sampling-based Planning/rrt_2D/plotting.py b/Sampling-based Planning/rrt_2D/plotting.py
index d8f136c..f7fc975 100644
--- a/Sampling-based Planning/rrt_2D/plotting.py	
+++ b/Sampling-based Planning/rrt_2D/plotting.py	
@@ -1,3 +1,9 @@
+"""
+Plotting tools for RRT_2D
+@author: huiming zhou
+"""
+
+
 import matplotlib.pyplot as plt
 import matplotlib.patches as patches
 
diff --git a/Sampling-based Planning/rrt_2D/rrt.py b/Sampling-based Planning/rrt_2D/rrt.py
index d449bfe..b8786d6 100644
--- a/Sampling-based Planning/rrt_2D/rrt.py	
+++ b/Sampling-based Planning/rrt_2D/rrt.py	
@@ -1,3 +1,9 @@
+"""
+RRT_2D
+@author: huiming zhou
+"""
+
+
 from rrt_2D import env
 from rrt_2D import plotting
 
diff --git a/Sampling-based Planning/rrt_2D/rrt_star.py b/Sampling-based Planning/rrt_2D/rrt_star.py
index 3a0e091..394dd1c 100644
--- a/Sampling-based Planning/rrt_2D/rrt_star.py	
+++ b/Sampling-based Planning/rrt_2D/rrt_star.py	
@@ -1,3 +1,9 @@
+"""
+RRT_star 2D
+@author: huiming zhou
+"""
+
+
 from rrt_2D import env
 from rrt_2D import plotting