diff --git a/data/mjcf/ant.xml b/data/mjcf/ant.xml
index 18ad38b38..311d96feb 100644
--- a/data/mjcf/ant.xml
+++ b/data/mjcf/ant.xml
@@ -6,62 +6,53 @@
   </custom>
   <default>
     <joint armature="1" damping="1" limited="true"/>
-    <geom conaffinity="0" condim="3" density="5.0" friction="1 0.5 0.5" margin="0.01" rgba="0.8 0.6 0.4 1"/>
+    <geom conaffinity="0" condim="3" density="5.0" friction="1.5 0.1 0.1" margin="0.01" rgba="0.8 0.6 0.4 1"/>
   </default>
-  <asset>
-    <texture builtin="gradient" height="100" rgb1="1 1 1" rgb2="0 0 0" type="skybox" width="100"/>
-    <texture builtin="flat" height="1278" mark="cross" markrgb="1 1 1" name="texgeom" random="0.01" rgb1="0.8 0.6 0.4" rgb2="0.8 0.6 0.4" type="cube" width="127"/>
-    <texture builtin="checker" height="100" name="texplane" rgb1="0 0 0" rgb2="0.8 0.8 0.8" type="2d" width="100"/>
-    <material name="MatPlane" reflectance="0.5" shininess="1" specular="1" texrepeat="60 60" texture="texplane"/>
-    <material name="geom" texture="texgeom" texuniform="true"/>
-  </asset>
   <worldbody>
-    <light cutoff="100" diffuse="1 1 1" dir="-0 0 -1.3" directional="true" exponent="1" pos="0 0 1.3" specular=".1 .1 .1"/>
-    <geom conaffinity="1" condim="3" material="MatPlane" name="floor" pos="0 0 0" rgba="0.8 0.9 0.8 1" size="40 40 40" type="plane"/>
     <body name="torso" pos="0 0 0.75">
       <geom name="torso_geom" pos="0 0 0" size="0.25" type="sphere"/>
-      <joint armature="0" damping="0" limited="false" margin="0.01" name="root" pos="0 0 0" type="free"/>
+      <!--joint armature="0" damping="0" limited="false" margin="0.01" name="root" pos="0 0 0" type="free"/-->
       <body name="front_left_leg" pos="0 0 0">
-        <geom fromto="0.0 0.0 0.0 0.2 0.2 0.0" name="aux_1_geom" size="0.08" type="capsule"/>
+        <geom fromto="0.0 0.0 0.0 0.2 0.2 0.0" name="aux_1_geom" size="0.08" type="capsule" rgba=".8 .5 .3 1"/>
         <body name="aux_1" pos="0.2 0.2 0">
-          <joint axis="0 0 1" name="hip_1" pos="0.0 0.0 0.0" range="-30 30" type="hinge"/>
-          <geom fromto="0.0 0.0 0.0 0.2 0.2 0.0" name="left_leg_geom" size="0.08" type="capsule"/>
-          <body pos="0.2 0.2 0">
-            <joint axis="-1 1 0" name="ankle_1" pos="0.0 0.0 0.0" range="30 70" type="hinge"/>
-            <geom fromto="0.0 0.0 0.0 0.4 0.4 0.0" name="left_ankle_geom" size="0.08" type="capsule"/>
+          <joint axis="0 0 1" name="hip_1" pos="0.0 0.0 0.0" range="-40 40" type="hinge"/>
+          <geom fromto="0.0 0.0 0.0 0.2 0.2 0.0" name="left_leg_geom" size="0.08" type="capsule" rgba=".8 .5 .3 1"/>
+          <body pos="0.2 0.2 0" name="front_left_foot">
+            <joint axis="-1 1 0" name="ankle_1" pos="0.0 0.0 0.0" range="30 100" type="hinge"/>
+            <geom fromto="0.0 0.0 0.0 0.4 0.4 0.0" name="left_ankle_geom" size="0.08" type="capsule" rgba=".8 .5 .3 1"/>
           </body>
         </body>
       </body>
       <body name="front_right_leg" pos="0 0 0">
         <geom fromto="0.0 0.0 0.0 -0.2 0.2 0.0" name="aux_2_geom" size="0.08" type="capsule"/>
         <body name="aux_2" pos="-0.2 0.2 0">
-          <joint axis="0 0 1" name="hip_2" pos="0.0 0.0 0.0" range="-30 30" type="hinge"/>
+          <joint axis="0 0 1" name="hip_2" pos="0.0 0.0 0.0" range="-40 40" type="hinge"/>
           <geom fromto="0.0 0.0 0.0 -0.2 0.2 0.0" name="right_leg_geom" size="0.08" type="capsule"/>
-          <body pos="-0.2 0.2 0">
-            <joint axis="1 1 0" name="ankle_2" pos="0.0 0.0 0.0" range="-70 -30" type="hinge"/>
+          <body pos="-0.2 0.2 0" name="front_right_foot">
+            <joint axis="1 1 0" name="ankle_2" pos="0.0 0.0 0.0" range="-100 -30" type="hinge"/>
             <geom fromto="0.0 0.0 0.0 -0.4 0.4 0.0" name="right_ankle_geom" size="0.08" type="capsule"/>
           </body>
         </body>
       </body>
-      <body name="back_leg" pos="0 0 0">
+      <body name="left_back_leg" pos="0 0 0">
         <geom fromto="0.0 0.0 0.0 -0.2 -0.2 0.0" name="aux_3_geom" size="0.08" type="capsule"/>
         <body name="aux_3" pos="-0.2 -0.2 0">
-          <joint axis="0 0 1" name="hip_3" pos="0.0 0.0 0.0" range="-30 30" type="hinge"/>
+          <joint axis="0 0 1" name="hip_3" pos="0.0 0.0 0.0" range="-40 40" type="hinge"/>
           <geom fromto="0.0 0.0 0.0 -0.2 -0.2 0.0" name="back_leg_geom" size="0.08" type="capsule"/>
-          <body pos="-0.2 -0.2 0">
-            <joint axis="-1 1 0" name="ankle_3" pos="0.0 0.0 0.0" range="-70 -30" type="hinge"/>
+          <body pos="-0.2 -0.2 0" name="left_back_foot">
+            <joint axis="-1 1 0" name="ankle_3" pos="0.0 0.0 0.0" range="-100 -30" type="hinge"/>
             <geom fromto="0.0 0.0 0.0 -0.4 -0.4 0.0" name="third_ankle_geom" size="0.08" type="capsule"/>
           </body>
         </body>
       </body>
       <body name="right_back_leg" pos="0 0 0">
-        <geom fromto="0.0 0.0 0.0 0.2 -0.2 0.0" name="aux_4_geom" size="0.08" type="capsule"/>
+        <geom fromto="0.0 0.0 0.0 0.2 -0.2 0.0" name="aux_4_geom" size="0.08" type="capsule" rgba=".8 .5 .3 1"/>
         <body name="aux_4" pos="0.2 -0.2 0">
-          <joint axis="0 0 1" name="hip_4" pos="0.0 0.0 0.0" range="-30 30" type="hinge"/>
-          <geom fromto="0.0 0.0 0.0 0.2 -0.2 0.0" name="rightback_leg_geom" size="0.08" type="capsule"/>
-          <body pos="0.2 -0.2 0">
-            <joint axis="1 1 0" name="ankle_4" pos="0.0 0.0 0.0" range="30 70" type="hinge"/>
-            <geom fromto="0.0 0.0 0.0 0.4 -0.4 0.0" name="fourth_ankle_geom" size="0.08" type="capsule"/>
+          <joint axis="0 0 1" name="hip_4" pos="0.0 0.0 0.0" range="-40 40" type="hinge"/>
+          <geom fromto="0.0 0.0 0.0 0.2 -0.2 0.0" name="rightback_leg_geom" size="0.08" type="capsule" rgba=".8 .5 .3 1"/>
+          <body pos="0.2 -0.2 0" name="right_back_foot">
+            <joint axis="1 1 0" name="ankle_4" pos="0.0 0.0 0.0" range="30 100" type="hinge"/>
+            <geom fromto="0.0 0.0 0.0 0.4 -0.4 0.0" name="fourth_ankle_geom" size="0.08" type="capsule" rgba=".8 .5 .3 1"/>
           </body>
         </body>
       </body>
diff --git a/data/mjcf/ground_plane.xml b/data/mjcf/ground_plane.xml
new file mode 100644
index 000000000..0212c7f1b
--- /dev/null
+++ b/data/mjcf/ground_plane.xml
@@ -0,0 +1,5 @@
+<mujoco model="ground_plane">
+  <worldbody>
+    <geom conaffinity="1" condim="3" name="floor" friction="0.8 0.1 0.1" pos="0 0 0" type="plane"/>
+  </worldbody>
+</mujoco>
diff --git a/data/mjcf/half_cheetah.xml b/data/mjcf/half_cheetah.xml
new file mode 100644
index 000000000..418eef56d
--- /dev/null
+++ b/data/mjcf/half_cheetah.xml
@@ -0,0 +1,88 @@
+<!-- Cheetah Model
+
+    The state space is populated with joints in the order that they are
+    defined in this file. The actuators also operate on joints.
+
+    State-Space (name/joint/parameter):
+        - rootx     slider      position (m)
+        - rootz     slider      position (m)
+        - rooty     hinge       angle (rad)
+        - bthigh    hinge       angle (rad)
+        - bshin     hinge       angle (rad)
+        - bfoot     hinge       angle (rad)
+        - fthigh    hinge       angle (rad)
+        - fshin     hinge       angle (rad)
+        - ffoot     hinge       angle (rad)
+        - rootx     slider      velocity (m/s)
+        - rootz     slider      velocity (m/s)
+        - rooty     hinge       angular velocity (rad/s)
+        - bthigh    hinge       angular velocity (rad/s)
+        - bshin     hinge       angular velocity (rad/s)
+        - bfoot     hinge       angular velocity (rad/s)
+        - fthigh    hinge       angular velocity (rad/s)
+        - fshin     hinge       angular velocity (rad/s)
+        - ffoot     hinge       angular velocity (rad/s)
+
+    Actuators (name/actuator/parameter):
+        - bthigh    hinge       torque (N m)
+        - bshin     hinge       torque (N m)
+        - bfoot     hinge       torque (N m)
+        - fthigh    hinge       torque (N m)
+        - fshin     hinge       torque (N m)
+        - ffoot     hinge       torque (N m)
+
+-->
+<mujoco model="cheetah">
+  <compiler angle="radian" coordinate="local" inertiafromgeom="true" settotalmass="14"/>
+  <default>
+    <joint armature=".1" damping=".01" limited="true" solimplimit="0 .8 .03" solreflimit=".02 1" stiffness="8"/>
+    <geom conaffinity="0" condim="3" contype="1" friction="0.8 .1 .1" rgba="0.8 0.6 .4 1" solimp="0.0 0.8 0.01" solref="0.02 1"/>
+    <motor ctrllimited="true" ctrlrange="-1 1"/>
+  </default>
+  <size nstack="300000" nuser_geom="1"/>
+  <option gravity="0 0 -9.81" timestep="0.01"/>
+  <worldbody>
+    <body name="torso" pos="0 0 .7">
+      <joint armature="0" axis="1 0 0" damping="0" limited="false" name="ignorex" pos="0 0 0" stiffness="0" type="slide"/>
+      <joint armature="0" axis="0 0 1" damping="0" limited="false" name="ignorez" pos="0 0 0" stiffness="0" type="slide"/>
+      <joint armature="0" axis="0 1 0" damping="0" limited="false" name="ignorey" pos="0 0 0" stiffness="0" type="hinge"/>
+      <geom fromto="-.5 0 0 .5 0 0" name="torso" size="0.046" type="capsule"/>
+      <geom axisangle="0 1 0 .87" name="head" pos=".6 0 .1" size="0.046 .15" type="capsule"/>
+      <!-- <site name='tip'  pos='.15 0 .11'/>-->
+      <body name="bthigh" pos="-.5 0 0">
+        <joint axis="0 1 0" damping="6" name="bthigh" pos="0 0 0" range="-.52 1.05" stiffness="240" type="hinge"/>
+        <geom axisangle="0 1 0 -3.8" name="bthigh" pos=".1 0 -.13" size="0.046 .145" type="capsule"/>
+        <body name="bshin" pos=".16 0 -.25">
+          <joint axis="0 1 0" damping="4.5" name="bshin" pos="0 0 0" range="-.785 .785" stiffness="180" type="hinge"/>
+          <geom axisangle="0 1 0 -2.03" name="bshin" pos="-.14 0 -.07" rgba="0.9 0.6 0.6 1" size="0.046 .15" type="capsule"/>
+          <body name="bfoot" pos="-.28 0 -.14">
+            <joint axis="0 1 0" damping="3" name="bfoot" pos="0 0 0" range="-.4 .785" stiffness="120" type="hinge"/>
+            <geom axisangle="0 1 0 -.27" name="bfoot" pos=".03 0 -.097" rgba="0.9 0.6 0.6 1" size="0.046 .094" type="capsule"/>
+            <inertial mass="10"/>
+          </body>
+        </body>
+      </body>
+      <body name="fthigh" pos=".5 0 0">
+        <joint axis="0 1 0" damping="4.5" name="fthigh" pos="0 0 0" range="-1.5 0.8" stiffness="180" type="hinge"/>
+        <geom axisangle="0 1 0 .52" name="fthigh" pos="-.07 0 -.12" size="0.046 .133" type="capsule"/>
+        <body name="fshin" pos="-.14 0 -.24">
+          <joint axis="0 1 0" damping="3" name="fshin" pos="0 0 0" range="-1.2 1.1" stiffness="120" type="hinge"/>
+          <geom axisangle="0 1 0 -.6" name="fshin" pos=".065 0 -.09" rgba="0.9 0.6 0.6 1" size="0.046 .106" type="capsule"/>
+          <body name="ffoot" pos=".13 0 -.18">
+            <joint axis="0 1 0" damping="1.5" name="ffoot" pos="0 0 0" range="-3.1 -0.3" stiffness="60" type="hinge"/>
+            <geom axisangle="0 1 0 -.6" name="ffoot" pos=".045 0 -.07" rgba="0.9 0.6 0.6 1" size="0.046 .07" type="capsule"/>
+            <inertial mass="10"/>
+          </body>
+        </body>
+      </body>
+    </body>
+  </worldbody>
+  <actuator>
+    <motor gear="120" joint="bthigh" name="bthigh"/>
+    <motor gear="90" joint="bshin" name="bshin"/>
+    <motor gear="60" joint="bfoot" name="bfoot"/>
+    <motor gear="120" joint="fthigh" name="fthigh"/>
+    <motor gear="60" joint="fshin" name="fshin"/>
+    <motor gear="30" joint="ffoot" name="ffoot"/>
+  </actuator>
+</mujoco>
diff --git a/data/mjcf/hopper.xml b/data/mjcf/hopper.xml
index 7f94e64dc..077160345 100644
--- a/data/mjcf/hopper.xml
+++ b/data/mjcf/hopper.xml
@@ -1,28 +1,31 @@
 <mujoco model="hopper">
   <compiler angle="degree" coordinate="global" inertiafromgeom="true"/>
   <default>
-    <joint armature="1" damping="1" />
-    <geom conaffinity="1" condim="1" contype="1" margin="0.001" material="geom" rgba="0.8 0.6 .4 1" solimp=".8 .8 .01" solref=".02 1"/>
+    <joint armature="1" damping="1" limited="true"/>
+    <geom conaffinity="1" condim="1" contype="1" margin="0.001" friction="0.8 .1 .1" material="geom" rgba="0.8 0.6 .4 1" solimp=".8 .8 .01" solref=".02 1"/>
     <motor ctrllimited="true" ctrlrange="-.4 .4"/>
   </default>
   <option integrator="RK4" timestep="0.002"/>
   <worldbody>
-    <light cutoff="100" diffuse="1 1 1" dir="-0 0 -1.3" directional="true" exponent="1" pos="0 0 1.3" specular=".1 .1 .1"/>
-    <geom conaffinity="1" condim="3" name="floor" pos="0 0 0" rgba="0.8 0.9 0.8 1" size="20 20 .125" type="plane" material="MatPlane"/>
-    <body name="torso" pos="0 0 1.25">
-      <joint armature="0" axis="1 0 0" damping="0" limited="false" name="rootx" pos="0 0 0" stiffness="0" type="slide"/>
-      <joint armature="0" axis="0 0 1" damping="0" limited="false" name="rootz" pos="0 0 0" ref="1.25" stiffness="0" type="slide"/>
-      <joint armature="0" axis="0 1 0" damping="0" limited="false" name="rooty" pos="0 0 1.25" stiffness="0" type="hinge"/>
-      <geom friction="0.9" fromto="0 0 1.45 0 0 1.05" name="torso_geom" size="0.05" type="capsule"/>
-      <body name="thigh" pos="0 0 1.05">
+    <!-- CHANGE: body pos="" deleted for all bodies (you can also set pos="0 0 0", it works)
+    Interpretation of body pos="" depends on coordinate="global" above.
+    Bullet doesn't support global coordinates in bodies, little motivation to fix this, as long as it works without pos="" as well.
+    After this change, Hopper still loads and works in MuJoCo simulator.
+    -->
+    <body name="torso">
+      <joint armature="0" axis="1 0 0" damping="0" limited="false" name="ignore1" pos="0 0 0" stiffness="0" type="slide"/>
+      <joint armature="0" axis="0 0 1" damping="0" limited="false" name="ignore2" pos="0 0 0" ref="1.25" stiffness="0" type="slide"/>
+      <joint armature="0" axis="0 1 0" damping="0" limited="false" name="ignore3" pos="0 0 0" stiffness="0" type="hinge"/>
+      <geom fromto="0 0 1.45 0 0 1.05" name="torso_geom" size="0.05" type="capsule"/>
+      <body name="thigh">
         <joint axis="0 -1 0" name="thigh_joint" pos="0 0 1.05" range="-150 0" type="hinge"/>
-        <geom friction="0.9" fromto="0 0 1.05 0 0 0.6" name="thigh_geom" size="0.05" type="capsule"/>
-        <body name="leg" pos="0 0 0.35">
+        <geom fromto="0 0 1.05 0 0 0.6" name="thigh_geom" size="0.05" type="capsule"/>
+        <body name="leg">
           <joint axis="0 -1 0" name="leg_joint" pos="0 0 0.6" range="-150 0" type="hinge"/>
-          <geom friction="0.9" fromto="0 0 0.6 0 0 0.1" name="leg_geom" size="0.04" type="capsule"/>
-          <body name="foot" pos="0.13/2 0 0.1">
+          <geom fromto="0 0 0.6 0 0 0.1" name="leg_geom" size="0.04" type="capsule"/>
+          <body name="foot">
             <joint axis="0 -1 0" name="foot_joint" pos="0 0 0.1" range="-45 45" type="hinge"/>
-            <geom friction="2.0" fromto="-0.13 0 0.1 0.26 0 0.1" name="foot_geom" size="0.06" type="capsule"/>
+            <geom fromto="-0.13 0 0.1 0.26 0 0.1" name="foot_geom" size="0.06" type="capsule"/>
           </body>
         </body>
       </body>
@@ -33,12 +36,4 @@
     <motor ctrllimited="true" ctrlrange="-1.0 1.0" gear="200.0" joint="leg_joint"/>
     <motor ctrllimited="true" ctrlrange="-1.0 1.0" gear="200.0" joint="foot_joint"/>
   </actuator>
-    <asset>
-        <texture type="skybox" builtin="gradient" rgb1=".4 .5 .6" rgb2="0 0 0"
-            width="100" height="100"/>        
-        <texture builtin="flat" height="1278" mark="cross" markrgb="1 1 1" name="texgeom" random="0.01" rgb1="0.8 0.6 0.4" rgb2="0.8 0.6 0.4" type="cube" width="127"/>
-        <texture builtin="checker" height="100" name="texplane" rgb1="0 0 0" rgb2="0.8 0.8 0.8" type="2d" width="100"/>
-        <material name="MatPlane" reflectance="0.5" shininess="1" specular="1" texrepeat="60 60" texture="texplane"/>
-        <material name="geom" texture="texgeom" texuniform="true"/>
-    </asset>
-</mujoco>
\ No newline at end of file
+</mujoco>
diff --git a/data/mjcf/humanoid_symmetric.xml b/data/mjcf/humanoid_symmetric.xml
index de2fee3f5..d7ba9f494 100644
--- a/data/mjcf/humanoid_symmetric.xml
+++ b/data/mjcf/humanoid_symmetric.xml
@@ -2,7 +2,7 @@
     <compiler angle="degree" inertiafromgeom="true"/>
     <default>
         <joint armature="1" damping="1" limited="true"/>
-        <geom conaffinity="1" condim="1" contype="1" margin="0.001" material="geom" rgba="0.8 0.6 .4 1"/>
+        <geom conaffinity="1" condim="3" friction="0.8 0.1 0.1" contype="1" margin="0.001" material="geom" rgba="0.8 0.6 .4 1"/>
         <motor ctrllimited="true" ctrlrange="-.4 .4"/>
     </default>
     <option integrator="RK4" iterations="50" solver="PGS" timestep="0.003">
@@ -12,18 +12,7 @@
     <visual>
         <map fogend="5" fogstart="3"/>
     </visual>
-    <asset>
-        <texture builtin="gradient" height="100" rgb1=".4 .5 .6" rgb2="0 0 0" type="skybox" width="100"/>
-        <!-- <texture builtin="gradient" height="100" rgb1="1 1 1" rgb2="0 0 0" type="skybox" width="100"/>-->
-        <texture builtin="flat" height="1278" mark="cross" markrgb="1 1 1" name="texgeom" random="0.01" rgb1="0.8 0.6 0.4" rgb2="0.8 0.6 0.4" type="cube" width="127"/>
-        <texture builtin="checker" height="100" name="texplane" rgb1="0 0 0" rgb2="0.8 0.8 0.8" type="2d" width="100"/>
-        <material name="MatPlane" reflectance="0.5" shininess="1" specular="1" texrepeat="60 60" texture="texplane"/>
-        <material name="geom" texture="texgeom" texuniform="true"/>
-    </asset>
     <worldbody>
-        <!-- light cutoff="100" diffuse="1 1 1" dir="-0 0 -1.3" directional="true" exponent="1" pos="0 0 1.3" specular=".1 .1 .1"/-->
-        <geom condim="3" friction="1 .1 .1" material="MatPlane" name="floor" pos="0 0 0" rgba="0.8 0.9 0.8 1" size="20 20 0.125" type="plane"/>
-        <!-- <geom condim="3" material="MatPlane" name="floor" pos="0 0 0" size="10 10 0.125" type="plane"/>-->
         <body name="torso" pos="0 0 1.4">
             <!--joint armature="0" damping="0" limited="false" name="root" pos="0 0 0" stiffness="0" type="free"/-->
             <geom fromto="0 -.07 0 0 .07 0" name="torso1" size="0.07" type="capsule"/>
diff --git a/data/mjcf/inverted_double_pendulum.xml b/data/mjcf/inverted_double_pendulum.xml
index a274e8c5d..755cefd44 100644
--- a/data/mjcf/inverted_double_pendulum.xml
+++ b/data/mjcf/inverted_double_pendulum.xml
@@ -36,7 +36,7 @@
         <body name="pole2" pos="0 0 0.6">
           <joint axis="0 1 0" name="hinge2" pos="0 0 0" type="hinge"/>
           <geom fromto="0 0 0 0 0 0.6" name="cpole2" rgba="0 0.7 0.7 1" size="0.045 0.3" type="capsule"/>
-          <site name="tip" pos="0 0 .6" size="0.01 0.01"/>
+          <!--site name="tip" pos="0 0 .6" size="0.01 0.01"/-->
         </body>
       </body>
     </body>
@@ -44,4 +44,4 @@
   <actuator>
     <motor ctrllimited="true" ctrlrange="-1 1" gear="500" joint="slider" name="slide"/>
   </actuator>
-</mujoco>
\ No newline at end of file
+</mujoco>
diff --git a/data/mjcf/inverted_pendulum.xml b/data/mjcf/inverted_pendulum.xml
index f8fbc1aad..b409b3b11 100644
--- a/data/mjcf/inverted_pendulum.xml
+++ b/data/mjcf/inverted_pendulum.xml
@@ -2,7 +2,7 @@
 	<compiler inertiafromgeom="true"/>
 	<default>
 		<joint armature="0" damping="1" limited="true"/>
-		<geom  friction="1 0.1 0.1" rgba="0.7 0.7 0 1"/>
+		<geom contype="0" friction="1 0.1 0.1" rgba="0.7 0.7 0 1"/>
 		<tendon/>
 		<motor ctrlrange="-3 3"/>
 	</default>
@@ -10,12 +10,12 @@
 	<size nstack="3000"/>
 	<worldbody>
 		<!--geom name="ground" type="plane" pos="0 0 0" /-->
-		<!-- <geom name="rail" pos="0 0 0" quat="0.707 0 0.707 0" rgba="0.3 0.3 0.7 1" size="0.02 1" type="capsule"/> /-->
-		<body name="cart1" pos="0 0 0">
+		<geom name="rail" pos="0 0 0" quat="0.707 0 0.707 0" rgba="0.3 0.3 0.7 1" size="0.02 1" type="capsule"/>
+		<body name="cart" pos="0 0 0">
 			<joint axis="1 0 0" limited="true" name="slider" pos="0 0 0" range="-1 1" type="slide"/>
 			<geom name="cart" pos="0 0 0" quat="0.707 0 0.707 0" size="0.1 0.1" type="capsule"/>
 			<body name="pole" pos="0 0 0">
-				<joint axis="0 1 0" name="hinge" pos="0 0 0" range="-90 90" type="hinge"/>
+				<joint axis="0 1 0" name="hinge" pos="0 0 0" limited="false" range="-90 90" type="hinge"/>
 				<geom fromto="0 0 0 0.001 0 0.6" name="cpole" rgba="0 0.7 0.7 1" size="0.049 0.3" type="capsule"/>
 				<!--                 <body name="pole2" pos="0.001 0 0.6"><joint name="hinge2" type="hinge" pos="0 0 0" axis="0 1 0"/><geom name="cpole2" type="capsule" fromto="0 0 0 0 0 0.6" size="0.05 0.3" rgba="0.7 0 0.7 1"/><site name="tip2" pos="0 0 .6"/></body>-->
 			</body>
@@ -24,4 +24,4 @@
 	<actuator>
 		<motor gear="100" joint="slider" name="slide"/>
 	</actuator>
-</mujoco>
\ No newline at end of file
+</mujoco>
diff --git a/data/mjcf/pusher.xml b/data/mjcf/pusher.xml
new file mode 100644
index 000000000..bac3d7ace
--- /dev/null
+++ b/data/mjcf/pusher.xml
@@ -0,0 +1,90 @@
+<mujoco model="pusher">
+  <compiler inertiafromgeom="true" angle="radian" coordinate="local"/>
+  <default>
+    <joint armature='0.04' damping="0" limited="true"/>
+    <geom friction=".8 .1 .1" density="300" margin="0.002" condim="1" contype="0" conaffinity="0"/>
+  </default>
+  <option timestep="0.01" gravity="0 0 0" integrator="RK4" />  
+  <worldbody>
+    <!--Arena-->
+    <geom name="table" type="plane" pos="0 0.5 -0.325" size="1 1 0.1" contype="1" conaffinity="1"/>
+    <!--Arm-->
+    <body name="shoulder_pan_link" pos="0 -0.6 0">
+      <geom name="e1" type="sphere" rgba="0.6 0.6 0.6 1" pos="-0.06 0.05 0.2" size="0.05" />
+      <geom name="e2" type="sphere" rgba="0.6 0.6 0.6 1" pos=" 0.06 0.05 0.2" size="0.05" />
+      <geom name="e1p" type="sphere" rgba="0.1 0.1 0.1 1" pos="-0.06 0.09 0.2" size="0.03" />
+      <geom name="e2p" type="sphere" rgba="0.1 0.1 0.1 1" pos=" 0.06 0.09 0.2" size="0.03" />
+      <geom name="sp" type="capsule" fromto="0 0 -0.4 0 0 0.2" size="0.1" />
+      <joint name="shoulder_pan_joint" type="hinge" pos="0 0 0" axis="0 0 1" range="-2.2854 1.714602" damping="0" />
+
+      <body name="shoulder_lift_link" pos="0.1 0 0">
+        <geom name="sl" type="capsule" fromto="0 -0.1 0 0 0.1 0" size="0.1" />
+        <joint name="shoulder_lift_joint" type="hinge" pos="0 0 0" axis="0 1 0" range="-0.5236 1.3963" damping="0" />
+
+        <body name="upper_arm_roll_link" pos="0 0 0">
+          <geom name="uar" type="capsule" fromto="-0.1 0 0 0.1 0 0" size="0.02" />
+          <joint name="upper_arm_roll_joint" type="hinge" pos="0 0 0" axis="1 0 0" range="-1.5 1.7" damping="0" />
+
+          <body name="upper_arm_link" pos="0 0 0">
+            <geom name="ua" type="capsule" fromto="0 0 0 0.4 0 0" size="0.06" />
+
+            <body name="elbow_flex_link" pos="0.4 0 0">
+              <geom name="ef" type="capsule" fromto="0 -0.02 0 0.0 0.02 0" size="0.06" />
+              <joint name="elbow_flex_joint" type="hinge" pos="0 0 0" axis="0 1 0" range="-2.3213 0" damping="0" />
+
+              <body name="forearm_roll_link" pos="0 0 0">
+                <geom name="fr" type="capsule" fromto="-0.1 0 0 0.1 0 0" size="0.02" />
+                <joint name="forearm_roll_joint" type="hinge" limited="true" pos="0 0 0" axis="1 0 0" damping="0" range="-1.5 1.5"/>
+
+                <body name="forearm_link" pos="0 0 0">
+                  <geom name="fa" type="capsule" fromto="0 0 0 0.291 0 0" size="0.05" />
+
+                  <body name="wrist_flex_link" pos="0.321 0 0">
+                    <geom name="wf" type="capsule" fromto="0 -0.02 0 0 0.02 0" size="0.01" />
+                    <joint name="wrist_flex_joint" type="hinge" pos="0 0 0" axis="0 1 0" range="-1.094 0" damping="0" />
+
+                    <body name="wrist_roll_link" pos="0 0 0">
+                      <joint name="wrist_roll_joint" type="hinge" pos="0 0 0" limited="true" axis="1 0 0" damping="0" range="-1.5 1.5"/>
+                      <body name="fingertip" pos="0 0 0">
+                        <geom name="tip_arml" type="sphere" pos="0.1 -0.1 0." size="0.01" />
+                        <geom name="tip_armr" type="sphere" pos="0.1 0.1 0." size="0.01" />
+                      </body>
+                      <geom type="capsule" fromto="0 -0.1 0. 0.0 +0.1 0" size="0.02" contype="1" conaffinity="1" />
+                      <geom type="capsule" fromto="0 -0.1 0. 0.1 -0.1 0" size="0.02" contype="1" conaffinity="1" />
+                      <geom type="capsule" fromto="0 +0.1 0. 0.1 +0.1 0." size="0.02" contype="1" conaffinity="1" />
+                    </body>
+                  </body>
+                </body>
+              </body>
+            </body>
+          </body>
+        </body>
+      </body>
+    </body>
+
+    <!--Object-->
+    <body name="object" pos="0.45 -0.05 -0.275" >
+      <geom rgba="1 1 1 0" type="sphere" size="0.05 0.05 0.05" density="0.00001" conaffinity="0"/>
+      <geom rgba="1 1 1 1" type="cylinder" size="0.05 0.05 0.05" density="0.00001" contype="1" conaffinity="0"/>
+      <joint name="object_x" type="slide" pos="0 0 0" axis="1 0 0" range="-10.3213 10.3" damping="0"/>
+      <joint name="object_y" type="slide" pos="0 0 0" axis="0 1 0" range="-10.3213 10.3" damping="0"/>
+    </body>
+    
+    <!--Target-->
+    <body name="target" pos="0.45 -0.05 -0.3230">
+      <geom rgba="1 0 0 1" type="cylinder" size="0.08 0.001 0.1" density='0.00001' contype="0" conaffinity="0"/>
+      <joint name="target_x" type="slide" pos="0 0 0" axis="1 0 0" range="-10.3213 10.3" damping="0"/>
+      <joint name="target_y" type="slide" pos="0 0 0" axis="0 1 0" range="-10.3213 10.3" damping="0"/> 
+    </body>
+  </worldbody>
+
+  <actuator>
+    <motor joint="shoulder_pan_joint" ctrlrange="-2.0 2.0" ctrllimited="true" />
+    <motor joint="shoulder_lift_joint" ctrlrange="-2.0 2.0" ctrllimited="true" />
+    <motor joint="upper_arm_roll_joint" ctrlrange="-2.0 2.0" ctrllimited="true" />
+    <motor joint="elbow_flex_joint" ctrlrange="-2.0 2.0" ctrllimited="true" />
+    <motor joint="forearm_roll_joint" ctrlrange="-2.0 2.0" ctrllimited="true" />
+    <motor joint="wrist_flex_joint" ctrlrange="-2.0 2.0" ctrllimited="true" />
+    <motor joint="wrist_roll_joint" ctrlrange="-2.0 2.0" ctrllimited="true"/>
+  </actuator>
+</mujoco>
diff --git a/data/mjcf/reacher.xml b/data/mjcf/reacher.xml
index 28ebd6712..82b224ff6 100644
--- a/data/mjcf/reacher.xml
+++ b/data/mjcf/reacher.xml
@@ -26,9 +26,9 @@
 			</body>
 		</body>
 		<!-- Target -->
-		<body name="target" pos=".1 -.1 .01">
-			<joint armature="0" axis="1 0 0" damping="0" limited="true" name="target_x" pos="0 0 0" range="-.27 .27" ref=".1" stiffness="0" type="slide"/>
-			<joint armature="0" axis="0 1 0" damping="0" limited="true" name="target_y" pos="0 0 0" range="-.27 .27" ref="-.1" stiffness="0" type="slide"/>
+		<body name="target" pos="0 0 .01">
+			<joint armature="0" axis="1 0 0" damping="0" limited="true" name="target_x" pos="0 0 0" range="-.27 .27" stiffness="0" type="slide"/>
+			<joint armature="0" axis="0 1 0" damping="0" limited="true" name="target_y" pos="0 0 0" range="-.27 .27" stiffness="0" type="slide"/>
 			<geom conaffinity="0" contype="0" name="target" pos="0 0 0" rgba="0.9 0.2 0.2 1" size=".009" type="sphere"/>
 		</body>
 	</worldbody>
@@ -36,4 +36,4 @@
 		<motor ctrllimited="true" ctrlrange="-1.0 1.0" gear="200.0" joint="joint0"/>
 		<motor ctrllimited="true" ctrlrange="-1.0 1.0" gear="200.0" joint="joint1"/>
 	</actuator>
-</mujoco>
\ No newline at end of file
+</mujoco>
diff --git a/data/mjcf/striker.xml b/data/mjcf/striker.xml
new file mode 100644
index 000000000..59898d74f
--- /dev/null
+++ b/data/mjcf/striker.xml
@@ -0,0 +1,100 @@
+<mujoco model="striker">
+  <compiler inertiafromgeom="true" angle="radian" coordinate="local"/>
+  <option timestep="0.01" gravity="0 0 0" integrator="RK4"/>
+
+  <default>
+	<joint armature='0.04' damping="0" limited="true"/>
+	<geom friction=".0 .0 .0" density="300" margin="0.002" condim="1" contype="0" conaffinity="0"/>
+  </default>
+
+  <worldbody>
+	<!--Arena-->
+	<geom name="table" type="plane" pos="0 0.5 -0.325" size="1 1 0.1" contype="1" conaffinity="1"/>
+	<!--Arm-->
+	<body name="shoulder_pan_link" pos="0 -0.6 0">
+	  <geom name="e1" type="sphere" rgba="0.6 0.6 0.6 1" pos="-0.06 0.05 0.2" size="0.05" />
+	  <geom name="e2" type="sphere" rgba="0.6 0.6 0.6 1" pos=" 0.06 0.05 0.2" size="0.05" />
+	  <geom name="e1p" type="sphere" rgba="0.1 0.1 0.1 1" pos="-0.06 0.09 0.2" size="0.03" />
+	  <geom name="e2p" type="sphere" rgba="0.1 0.1 0.1 1" pos=" 0.06 0.09 0.2" size="0.03" />
+	  <geom name="sp" type="capsule" fromto="0 0 -0.4 0 0 0.2" size="0.1" />
+	  <joint name="shoulder_pan_joint" type="hinge" pos="0 0 0" axis="0 0 1" range="-2.2854 1.714602" damping="0" />
+
+	  <body name="shoulder_lift_link" pos="0.1 0 0">
+		<geom name="sl" type="capsule" fromto="0 -0.1 0 0 0.1 0" size="0.1" />
+		<joint name="shoulder_lift_joint" type="hinge" pos="0 0 0" axis="0 1 0" range="-0.5236 1.3963" damping="0" />
+
+		<body name="upper_arm_roll_link" pos="0 0 0">
+		  <geom name="uar" type="capsule" fromto="-0.1 0 0 0.1 0 0" size="0.02" />
+		  <joint name="upper_arm_roll_joint" type="hinge" pos="0 0 0" axis="1 0 0" range="-1.5 1.7" damping="0" />
+
+		  <body name="upper_arm_link" pos="0 0 0">
+			<geom name="ua" type="capsule" fromto="0 0 0 0.4 0 0" size="0.06" />
+
+			<body name="elbow_flex_link" pos="0.4 0 0">
+			  <geom name="ef" type="capsule" fromto="0 -0.02 0 0.0 0.02 0" size="0.06" />
+			  <joint name="elbow_flex_joint" type="hinge" pos="0 0 0" axis="0 1 0" range="-2.3213 0" damping="0" />
+
+			  <body name="forearm_roll_link" pos="0 0 0">
+				<geom name="fr" type="capsule" fromto="-0.1 0 0 0.1 0 0" size="0.02" />
+				<joint name="forearm_roll_joint" type="hinge" limited="true" pos="0 0 0" axis="1 0 0" damping="0" range="-1.5 1.5"/>
+
+				<body name="forearm_link" pos="0 0 0">
+				  <geom name="fa" type="capsule" fromto="0 0 0 0.291 0 0" size="0.05" />
+
+				  <body name="wrist_flex_link" pos="0.321 0 0">
+					<geom name="wf" type="capsule" fromto="0 -0.02 0 0 0.02 0" size="0.01" />
+					<joint name="wrist_flex_joint" type="hinge" pos="0 0 0" axis="0 1 0" range="-1.094 0" damping="0" />
+
+					<body name="wrist_roll_link" pos="0 0 0">
+					  <joint name="wrist_roll_joint" type="hinge" pos="0 0 0" limited="true" axis="1 0 0" damping="0" range="-1.5 1.5"/>
+					  <body name="fingertip" pos="0 0 0">
+						<geom name="tip_arml" type="box" pos="0.017 0 0" size="0.003 0.12 0.05" conaffinity="1" contype="1"  />
+					  </body>
+					  <geom type="capsule" fromto="0 -0.1 0. 0.0 +0.1 0" size="0.02" conaffinity="1" contype="1"  />
+					</body>
+				  </body>
+				</body>
+			  </body>
+			</body>
+		  </body>
+		</body>
+	  </body>
+	</body>
+
+	<!--Object-->
+	<body name="object" pos="0 0 -0.270" >
+	  <geom type="sphere" rgba="1 1 1 1" pos="0 0 0" size="0.05 0.05 0.05" contype="1" conaffinity="0"/>
+	  <joint name="object_x" armature="0.1" type="slide" pos="0 0 0" axis="1 0 0" range="-10.3213 10.3" damping="0.5"/>
+	  <joint name="object_y" armature="0.1" type="slide" pos="0 0 0" axis="0 1 0" range="-10.3213 10.3" damping="0.5"/>
+	</body>
+
+	<!--Target-->
+	<body name="target" pos="0.0 0.0 -0.3230">
+	  <geom rgba="1. 1. 1. 0" pos="0 0 0" type="box" size="0.01 0.01 0.01" contype="0" conaffinity="0"/>
+	  <body pos="0 0 0">
+		<geom rgba="1. 1. 1. 1" pos="0 0.075 0.04" type="box" size="0.032 0.001 0.04" contype="0" conaffinity="1"/>
+	  </body>
+	  <body name="coaster" pos="0 0 0">
+		<geom rgba="1. 1. 1. 1" type="cylinder" size="0.08 0.001 0.1" density='1000000' contype="0" conaffinity="0"/>
+	  </body>
+	  <body pos="0 0 0" axisangle="0 0 1 0.785">
+		<geom rgba="1. 1. 1. 1" pos="0 0.075 0.04" type="box" size="0.032 0.001 0.04" contype="0" conaffinity="1"/>
+	  </body>
+	  <body pos="0 0 0" axisangle="0 0 1 -0.785">
+		<geom rgba="1. 1. 1. 1" pos="0 0.075 0.04" type="box" size="0.032 0.001 0.04" contype="0" conaffinity="1"/>
+	  </body>
+	  <joint name="target_free" type="free" pos="0 0 0" limited="false" damping="0"/>
+	</body>
+  </worldbody>
+
+  <actuator>
+	<motor joint="shoulder_pan_joint" ctrlrange="-3.0 3.0" ctrllimited="true" />
+	<motor joint="shoulder_lift_joint" ctrlrange="-3.0 3.0" ctrllimited="true" />
+	<motor joint="upper_arm_roll_joint" ctrlrange="-3.0 3.0" ctrllimited="true" />
+	<motor joint="elbow_flex_joint" ctrlrange="-3.0 3.0" ctrllimited="true" />
+	<motor joint="forearm_roll_joint" ctrlrange="-3.0 3.0" ctrllimited="true" />
+	<motor joint="wrist_flex_joint" ctrlrange="-3.0 3.0" ctrllimited="true" />
+	<motor joint="wrist_roll_joint" ctrlrange="-3.0 3.0" ctrllimited="true"/>
+  </actuator>
+
+</mujoco>
diff --git a/data/mjcf/thrower.xml b/data/mjcf/thrower.xml
new file mode 100644
index 000000000..fcb39f524
--- /dev/null
+++ b/data/mjcf/thrower.xml
@@ -0,0 +1,127 @@
+<mujoco model="thrower">
+  <compiler inertiafromgeom="true" angle="radian" coordinate="local"/>
+  <default>
+	<joint armature='0.75' damping="0" limited="true"/>
+	<geom friction=".8 .1 .1" density="300" margin="0.002" condim="1" contype="0" conaffinity="0"/>
+  </default>
+
+  <worldbody>
+	<!--Arena-->
+	<geom type="plane" pos="0 0.5 -0.325" size="1 1 0.1" contype="1" conaffinity="1"/>
+	<!--Arm-->
+	<body name="shoulder_pan_link" pos="0 -0.6 0">
+	  <geom name="e1" type="sphere" rgba="0.6 0.6 0.6 1" pos="-0.06 0.05 0.2" size="0.05" density="0.0001"/>
+	  <geom name="e2" type="sphere" rgba="0.6 0.6 0.6 1" pos=" 0.06 0.05 0.2" size="0.05" density="0.0001"/>
+	  <geom name="e1p" type="sphere" rgba="0.1 0.1 0.1 1" pos="-0.06 0.09 0.2" size="0.03" density="0.0001"/>
+	  <geom name="e2p" type="sphere" rgba="0.1 0.1 0.1 1" pos=" 0.06 0.09 0.2" size="0.03" density="0.0001"/>
+	  <geom name="sp" type="capsule" fromto="0 0 -0.4 0 0 0.2" size="0.1" density="1"/>
+	  <joint name="shoulder_pan_joint" type="hinge" pos="0 0 0" axis="0 0 1" range="-0.4854 1.214602" damping="1.0"/>
+
+	  <body name="shoulder_lift_link" pos="0.1 0 0">
+		<geom name="sl" type="capsule" fromto="0 -0.1 0 0 0.1 0" size="0.1" density="0.0001"/>
+		<joint name="shoulder_lift_joint" type="hinge" pos="0 0 0" axis="0 1 0" range="-0.5236 0.7963" damping="1.0"/>
+
+		<body name="upper_arm_roll_link" pos="0 0 0">
+		  <geom name="uar" type="capsule" fromto="-0.1 0 0 0.1 0 0" size="0.02" density="0.0001"/>
+		  <joint name="upper_arm_roll_joint" type="hinge" pos="0 0 0" axis="1 0 0" range="-1.5 1.7" damping="1.0"/>
+
+		  <body name="upper_arm_link" pos="0 0 0">
+			<geom name="ua" type="capsule" fromto="0 0 0 0.4 0 0" size="0.06" density="0.0001"/>
+
+			<body name="elbow_flex_link" pos="0.4 0 0">
+			  <geom name="ef" type="capsule" fromto="0 -0.02 0 0.0 0.02 0" size="0.06" density="0.0001"/>
+			  <joint name="elbow_flex_joint" type="hinge" pos="0 0 0" axis="0 1 0" range="-0.7 0.7" damping="1.0"/>
+
+			  <body name="forearm_roll_link" pos="0 0 0">
+				<geom name="fr" type="capsule" fromto="-0.1 0 0 0.1 0 0" size="0.02" density="0.0001"/>
+				<joint name="forearm_roll_joint" type="hinge" limited="true" pos="0 0 0" axis="1 0 0" damping="1.0" range="-1.5 1.5"/>
+
+				<body name="forearm_link" pos="0 0 0" axisangle="1 0 0 0.392">
+				  <geom name="fa" type="capsule" fromto="0 0 0 0 0 0.291" size="0.05" density="0.0001"/>
+
+				  <body name="wrist_flex_link" pos="0 0 0.321" axisangle="0 0 1 1.57">
+					<geom name="wf" type="capsule" fromto="0 -0.02 0 0 0.02 0" size="0.01" density="0.0001"/>
+					<joint name="wrist_flex_joint" type="hinge" pos="0 0 0" axis="0 0 1" range="-1.0 1.0" damping="1.0" />
+
+					<body name="wrist_roll_link" pos="0 0 0" axisangle="0 1 0 -1.178">
+					  <joint name="wrist_roll_joint" type="hinge" pos="0 0 0" limited="true" axis="0 1 0" damping="1.0" range="0 2.25"/>
+					  <geom type="capsule" fromto="0 -0.05 0 0 0.05 0" size="0.01" contype="1" conaffinity="1" density="0.0001"/>
+					  <body name="fingertip" pos="0 0 0" axisangle="0 0 1 0.392">
+						<geom type="capsule" fromto="0 0.025 0 0 0.075 0.075" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+						<geom type="capsule" fromto="0 0.075 0.075 0 0.075 0.15" size="0.005" contype="1" conaffinity="1" density=".0001"/>
+						<geom type="capsule" fromto="0 0.075 0.15 0 0 0.225" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+					  </body>
+					  <body pos="0 0 0" axisangle="0 0 1 1.57">
+						<geom type="capsule" fromto="0 0.025 0 0 0.075 0.075" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+						<geom type="capsule" fromto="0 0.075 0.075 0 0.075 0.15" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+						<geom type="capsule" fromto="0 0.075 0.15 0 0 0.225" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+					  </body>
+					  <body pos="0 0 0" axisangle="0 0 1 1.178">
+						<geom type="capsule" fromto="0 0.025 0 0 0.075 0.075" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+						<geom type="capsule" fromto="0 0.075 0.075 0 0.075 0.15" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+						<geom type="capsule" fromto="0 0.075 0.15 0 0 0.225" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+					  </body>
+					  <body pos="0 0 0" axisangle="0 0 1 0.785">
+						<geom type="capsule" fromto="0 0.025 0 0 0.075 0.075" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+						<geom type="capsule" fromto="0 0.075 0.075 0 0.075 0.15" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+						<geom type="capsule" fromto="0 0.075 0.15 0 0 0.225" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+					  </body>
+					  <body pos="0 0 0" axisangle="0 0 1 1.96">
+						<geom type="capsule" fromto="0 0.025 0 0 0.075 0.075" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+						<geom type="capsule" fromto="0 0.075 0.075 0 0.075 0.15" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+						<geom type="capsule" fromto="0 0.075 0.15 0 0 0.225" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+					  </body>
+					  <body pos="0 0 0" axisangle="0 0 1 2.355">
+						<geom type="capsule" fromto="0 0.025 0 0 0.075 0.075" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+						<geom type="capsule" fromto="0 0.075 0.075 0 0.075 0.15" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+						<geom type="capsule" fromto="0 0.075 0.15 0 0 0.225" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+					  </body>
+					  <body pos="0 0 0" axisangle="0 0 1 2.74">
+						<geom type="capsule" fromto="0 0.025 0 0 0.075 0.075" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+						<geom type="capsule" fromto="0 0.075 0.075 0 0.075 0.15" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+						<geom type="capsule" fromto="0 0.075 0.15 0 0 0.225" size="0.005" contype="1" conaffinity="1" density="0.0001"/>
+					  </body>
+					</body>
+				  </body>
+				</body>
+			  </body>
+			</body>
+		  </body>
+		</body>
+	  </body>
+	</body>
+
+	<!--Object-->
+	<body name="object" pos="0.5 -0.8 0.275">
+	  <geom rgba="1. 1. 1. 1" type="sphere" size="0.03 0.03 0.1" density='25' contype="1" conaffinity="1"/>
+	  <joint name="object_free" type="free" armature='0' damping="0" limited="false"/>
+	</body>
+
+	<!--Target-->
+	<body name="target" pos="0.575 0.5 -0.328">
+	  <geom rgba="1 1 1 1" type="box" pos="0 0 0.005" size="0.075 0.075 0.001" contype="1" conaffinity="1" density="1000"/>
+	  <geom rgba="1 1 1 1" type="box" pos="0.0 0.075 0.034" size="0.075 0.001 0.03" contype="1" conaffinity="0"/>
+	  <geom rgba="1 1 1 1" type="box" pos="0.0 -0.075 0.034" size="0.075 0.001 0.03" contype="1" conaffinity="0"/>
+	  <geom rgba="1 1 1 1" type="box" pos="0.075 0 0.034" size="0.001 0.075 0.03" contype="1" conaffinity="0"/>
+	  <geom rgba="1 1 1 1" type="box" pos="-0.076 0 0.034" size="0.001 0.075 0.03" contype="1" conaffinity="0"/>
+	  <geom rgba="1 1 1 1" type="capsule" fromto="0.073 0.073 0.0075 0.073 0.073 0.06" size="0.005" contype="1" conaffinity="0"/>
+	  <geom rgba="1 1 1 1" type="capsule" fromto="0.073 -0.073 0.0075 0.073 -0.073 0.06" size="0.005" contype="1" conaffinity="0"/>
+	  <geom rgba="1 1 1 1" type="capsule" fromto="-0.073 0.073 0.0075 -0.073 0.073 0.06" size="0.005" contype="1" conaffinity="0"/>
+	  <geom rgba="1 1 1 1" type="capsule" fromto="-0.073 -0.073 0.0075 -0.073 -0.073 0.06" size="0.005" contype="1" conaffinity="0"/>
+	  <joint name="target_x" type="slide" pos="0 0 0" axis="1 0 0" range="-10.3213 10.3" damping="0"/>
+	  <joint name="target_y" type="slide" pos="0 0 0" axis="0 1 0" range="-10.3213 10.3" damping="0"/>
+	</body>
+
+  </worldbody>
+
+  <actuator>
+	<motor joint="shoulder_pan_joint" ctrlrange="-10.0 10.0" ctrllimited="true" />
+	<motor joint="shoulder_lift_joint" ctrlrange="-10.0 10.0" ctrllimited="true" />
+	<motor joint="upper_arm_roll_joint" ctrlrange="-10.0 10.0" ctrllimited="true" />
+	<motor joint="elbow_flex_joint" ctrlrange="-10.0 10.0" ctrllimited="true" />
+	<motor joint="forearm_roll_joint" ctrlrange="-15.0 15.0" ctrllimited="true" />
+	<motor joint="wrist_flex_joint" ctrlrange="-15.0 15.0" ctrllimited="true" />
+	<motor joint="wrist_roll_joint" ctrlrange="-15.0 15.0" ctrllimited="true"/>
+  </actuator>
+
+</mujoco>
diff --git a/data/mjcf/walker2d.xml b/data/mjcf/walker2d.xml
new file mode 100644
index 000000000..f1905c067
--- /dev/null
+++ b/data/mjcf/walker2d.xml
@@ -0,0 +1,52 @@
+<mujoco model="walker2d">
+  <compiler angle="degree" coordinate="global" inertiafromgeom="true"/>
+  <default>
+    <joint armature="0.01" damping=".1" limited="true"/>
+    <geom conaffinity="0" condim="3" contype="1" density="1000" friction="0.8 .1 .1" rgba="0.8 0.6 .4 1"/>
+  </default>
+  <option integrator="RK4" timestep="0.002"/>
+  <worldbody>
+    <!-- CHANGES: see hopper.xml -->
+    <body name="torso">
+      <joint armature="0" axis="1 0 0" damping="0" limited="false" name="ignorex" pos="0 0 0" stiffness="0" type="slide"/>
+      <joint armature="0" axis="0 0 1" damping="0" limited="false" name="ignorez" pos="0 0 0" ref="1.25" stiffness="0" type="slide"/>
+      <joint armature="0" axis="0 1 0" damping="0" limited="false" name="ignorey" pos="0 0 0" stiffness="0" type="hinge"/>
+      <geom fromto="0 0 1.45 0 0 1.05" name="torso_geom" size="0.05" type="capsule"/>
+      <body name="thigh">
+        <joint axis="0 -1 0" name="thigh_joint" pos="0 0 1.05" range="-150 0" type="hinge"/>
+        <geom fromto="0 0 1.05 0 0 0.6" name="thigh_geom" size="0.05" type="capsule"/>
+        <body name="leg">
+          <joint axis="0 -1 0" name="leg_joint" pos="0 0 0.6" range="-150 0" type="hinge"/>
+          <geom fromto="0 0 0.6 0 0 0.1" name="leg_geom" size="0.04" type="capsule"/>
+          <body name="foot">
+            <joint axis="0 -1 0" name="foot_joint" pos="0 0 0.1" range="-45 45" type="hinge"/>
+            <geom fromto="-0.0 0 0.1 0.2 0 0.1" name="foot_geom" size="0.06" type="capsule"/>
+          </body>
+        </body>
+      </body>
+      <!-- copied and then replace thigh->thigh_left, leg->leg_left, foot->foot_right -->
+      <body name="thigh_left">
+        <joint axis="0 -1 0" name="thigh_left_joint" pos="0 0 1.05" range="-150 0" type="hinge"/>
+        <geom fromto="0 0 1.05 0 0 0.6" name="thigh_left_geom" rgba=".7 .3 .6 1" size="0.05" type="capsule"/>
+        <body name="leg_left">
+          <joint axis="0 -1 0" name="leg_left_joint" pos="0 0 0.6" range="-150 0" type="hinge"/>
+          <geom fromto="0 0 0.6 0 0 0.1" name="leg_left_geom" rgba=".7 .3 .6 1" size="0.04" type="capsule"/>
+          <body name="foot_left">
+            <joint axis="0 -1 0" name="foot_left_joint" pos="0 0 0.1" range="-45 45" type="hinge"/>
+            <geom fromto="-0.0 0 0.1 0.2 0 0.1" name="foot_left_geom" rgba=".7 .3 .6 1" size="0.06" type="capsule"/>
+          </body>
+        </body>
+      </body>
+    </body>
+  </worldbody>
+  <actuator>
+    <!-- <motor joint="torso_joint" ctrlrange="-100.0 100.0" isctrllimited="true"/>-->
+    <motor ctrllimited="true" ctrlrange="-1.0 1.0" gear="100" joint="thigh_joint"/>
+    <motor ctrllimited="true" ctrlrange="-1.0 1.0" gear="100" joint="leg_joint"/>
+    <motor ctrllimited="true" ctrlrange="-1.0 1.0" gear="100" joint="foot_joint"/>
+    <motor ctrllimited="true" ctrlrange="-1.0 1.0" gear="100" joint="thigh_left_joint"/>
+    <motor ctrllimited="true" ctrlrange="-1.0 1.0" gear="100" joint="leg_left_joint"/>
+    <motor ctrllimited="true" ctrlrange="-1.0 1.0" gear="100" joint="foot_left_joint"/>
+    <!-- <motor joint="finger2_rot" ctrlrange="-20.0 20.0" isctrllimited="true"/>-->
+  </actuator>
+</mujoco>
