diff --git a/README.md b/README.md
index 357633c..274aab1 100644
--- a/README.md
+++ b/README.md
@@ -1,54 +1,48 @@
 ## go2_urdf
-This repository contains the urdf model of go2.
+This repository contains the urdf/xacro model of go2.
 
 
 ## Build the library
-Create a new catkin workspace:
+Create a new workspace:
 ```
 # Create the directories
 # Do not forget to change <...> parts
-mkdir -p <directory_to_ws>/<catkin_ws_name>/src
-cd <directory_to_ws>/<catkin_ws_name>/
-
-# Initialize the catkin workspace
-catkin init
+mkdir -p <directory_to_ws>/<ws_name>/src
+cd <directory_to_ws>/<ws_name>/
 ```
 
 Clone this library:
 ```
 # Navigate to the directory of src
 # Do not forget to change <...> parts
-cd <directory_to_ws>/<catkin_ws_name>/src
+cd <directory_to_ws>/<ws_name>/src
 git clone git@github.com:unitreerobotics/go2_urdf.git
 ```
 
 Build:
 ```
 # Build it
-catkin build
+colcon build --symlink-install
 
 # Source it
-source <directory_to_ws>/<catkin_ws_name>/devel/setup.bash
+source <directory_to_ws>/<ws_name>/devel/setup.bash
 ```
 
-
-
 ## Run the library
 ```
-# Show urdf model of go2 in Rviz
+# Show the go2 model in Rviz
 roslaunch go2_description go2_rviz.launch
 
 ```
 
-## When used for isaac gym or other similiar engine 
+## Note - isaac gym (or other similiar engine) usage
 
 Collision parameters in urdf can be amended to better train the robot:
 
-Open "go2_description.urdf" in "./go2_description/urdf",
-and amend the ` box size="0.213 0.0245 0.034" ` in links of "FL_thigh", "FR_thigh", "RL_thigh", "RR_thigh".
-
-For example, change previous values to ` box size="0.11 0.0245 0.034" ` means the length of the thigh is shortened from 0.213 to 0.11, which can avoid unnecessary collision between the thigh link and the calf link. 
-
-The collision model before and after the above amendment are shown as "Normal_collision_model.png" and "Amended_collision_model.png" respectively.
-
+Open "go2_description.urdf" in "./go2_description/urdf" and amend
+`box size="0.213 0.0245 0.034"` in the "FL_thigh", "FR_thigh", "RL_thigh", 
+"RR_thigh" links.
 
+For example, changing to `box size="0.11 0.0245 0.034"` shortens the length of 
+the thigh is shortened from 0.213 to 0.11, which may avoid unnecessary collisions 
+between the thigh link and the calf link.
diff --git a/meshes/calf.dae b/meshes/calf.dae
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diff --git a/meshes/calf_mirror.dae b/meshes/calf_mirror.dae
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diff --git a/meshes/foot.dae b/meshes/foot.dae
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diff --git a/meshes/hip.dae b/meshes/hip.dae
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diff --git a/meshes/thigh.dae b/meshes/thigh.dae
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diff --git a/meshes/thigh_mirror.dae b/meshes/thigh_mirror.dae
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diff --git a/meshes/trunk.dae b/meshes/trunk.dae
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diff --git a/xacro/const.xacro b/xacro/const.xacro
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diff --git a/xacro/leg.xacro b/xacro/leg.xacro
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diff --git a/xacro/materials.xacro b/xacro/materials.xacro
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diff --git a/xacro/robot.xacro b/xacro/robot.xacro
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diff --git a/xacro/transmission.xacro b/xacro/transmission.xacro
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