Example world: use 1.11 and auto inertials

Adjust geometry slightly and set density to retain
the same mass values and approximately the same inertia
matrix.

Signed-off-by: Steve Peters <scpeters@openrobotics.org>

Author: scpeters

examples/worlds/set_model_state.sdf

@@ -5,7 +5,7 @@
   The initial joint position should be 90 degrees, and the initial joint
   velocity should be -30 degrees / second.
 -->
-<sdf version="1.6">
+<sdf version="1.11">
   <world name="set_model_state">
     <plugin
       filename="gz-sim-physics-system"
@@ -56,25 +56,15 @@
       </link>
     </model>
     <model name="model_state_example_degrees">
-      <pose>0 0 0.005 0 0 0</pose>
+      <pose>0 0 0.04 0 0 0</pose>
       <link name="base_link">
-        <pose>0.0 0.0 0.0 0 0 0</pose>
-        <inertial>
-          <inertia>
-            <ixx>2.501</ixx>
-            <ixy>0</ixy>
-            <ixz>0</ixz>
-            <iyy>2.501</iyy>
-            <iyz>0</iyz>
-            <izz>5</izz>
-          </inertia>
-          <mass>120.0</mass>
+        <inertial auto="true">
+          <density>6000</density>
         </inertial>
         <visual name="base_visual">
-          <pose>0.0 0.0 0.0 0 0 0</pose>
           <geometry>
             <box>
-              <size>0.5 0.5 0.01</size>
+              <size>0.5 0.5 0.08</size>
             </box>
           </geometry>
           <material>
@@ -84,27 +74,17 @@
           </material>
         </visual>
         <collision name="base_collision">
-          <pose>0.0 0.0 0.0 0 0 0</pose>
           <geometry>
             <box>
-              <size>0.5 0.5 0.01</size>
+              <size>0.5 0.5 0.08</size>
             </box>
           </geometry>
         </collision>
       </link>
       <link name="rotor">
         <pose>0.0 0.0 1.0 0.0 0 0</pose>
-        <inertial>
-          <pose>0.0 0.0 0.0 0 0 0</pose>
-          <inertia>
-            <ixx>0.032</ixx>
-            <ixy>0</ixy>
-            <ixz>0</ixz>
-            <iyy>0.032</iyy>
-            <iyz>0</iyz>
-            <izz>0.00012</izz>
-          </inertia>
-          <mass>0.6</mass>
+        <inertial auto="true">
+          <density>192</density>
         </inertial>
         <visual name="visual">
           <geometry>
@@ -155,23 +135,13 @@
     <model name="model_state_example_radians">
       <pose>1.0 0 0.005 0 0 0</pose>
       <link name="base_link">
-        <pose>0.0 0.0 0.0 0 0 0</pose>
-        <inertial>
-          <inertia>
-            <ixx>2.501</ixx>
-            <ixy>0</ixy>
-            <ixz>0</ixz>
-            <iyy>2.501</iyy>
-            <iyz>0</iyz>
-            <izz>5</izz>
-          </inertia>
-          <mass>120.0</mass>
+        <inertial auto="true">
+          <density>6000</density>
         </inertial>
         <visual name="base_visual">
-          <pose>0.0 0.0 0.0 0 0 0</pose>
           <geometry>
             <box>
-              <size>0.5 0.5 0.01</size>
+              <size>0.5 0.5 0.08</size>
             </box>
           </geometry>
           <material>
@@ -181,27 +151,17 @@
           </material>
         </visual>
         <collision name="base_collision">
-          <pose>0.0 0.0 0.0 0 0 0</pose>
           <geometry>
             <box>
-              <size>0.5 0.5 0.01</size>
+              <size>0.5 0.5 0.08</size>
             </box>
           </geometry>
         </collision>
       </link>
       <link name="rotor">
         <pose>0.0 0.0 1.0 0.0 0 0</pose>
-        <inertial>
-          <pose>0.0 0.0 0.0 0 0 0</pose>
-          <inertia>
-            <ixx>0.032</ixx>
-            <ixy>0</ixy>
-            <ixz>0</ixz>
-            <iyy>0.032</iyy>
-            <iyz>0</iyz>
-            <izz>0.00012</izz>
-          </inertia>
-          <mass>0.6</mass>
+        <inertial auto="true">
+          <density>192</density>
         </inertial>
         <visual name="visual">
           <geometry>