<!-- Link -->
<element name="link" required="*">
  <description>A physical link with inertia, collision, and visual properties. A link must be a child of a model, and any number of links may exist in a model.</description>

  <attribute name="name" type="string" default="__default__" required="1">
    <description>A unique name for the link within the scope of the model.</description>
  </attribute>

  <element name="gravity" type="bool" default="true" required="0">
    <description>If true, the link is affected by gravity.</description>
  </element>

  <element name="enable_wind" type="bool" default="false" required="0">
    <description>If true, the link is affected by the wind.</description>
  </element>

  <element name="self_collide" type="bool" default="false" required="0">
    <description>If true, the link can collide with other links in the model. Two links within a model will collide if link1.self_collide OR link2.self_collide. Links connected by a joint will never collide.</description>
  </element>

  <element name="kinematic" type="bool" default="false" required="0">
    <description>If true, the link is kinematic only</description>
  </element>

  <element name="must_be_base_link" type="bool" default="false" required="0">
    <description>If true, the link will have 6DOF and be a direct child of world.</description>
  </element>

  <element name="velocity_decay" required="0">
    <description>Exponential damping of the link's velocity.</description>
    <element name="linear" type="double" default="0.0" required="0">
      <description>Linear damping</description>
    </element>
    <element name="angular" type="double" default="0.0" required="0">
      <description>Angular damping</description>
    </element>
  </element> <!-- End velocity decay -->

  <include filename="frame.sdf" required="*"/>
  <include filename="pose.sdf" required="0"/>
  <include filename="inertial.sdf" required="0"/>
  <include filename="collision.sdf" required="*"/>
  <include filename="visual.sdf" required="*"/>
  <include filename="sensor.sdf" required="*"/>
  <include filename="projector.sdf" required="*"/>
  <include filename="audio_sink.sdf" required="*"/>
  <include filename="audio_source.sdf" required="*"/>
  <include filename="battery.sdf" required="*"/>
  <include filename="light.sdf" required="*"/>

</element> <!-- End Link -->
