<?xml version="1.0"?><gz:world   xmlns:gz='http://playerstage.sourceforge.net/gazebo/xmlschema/#gz'  xmlns:model='http://playerstage.sourceforge.net/gazebo/xmlschema/#model'  xmlns:window='http://playerstage.sourceforge.net/gazebo/xmlschema/#window'  xmlns:param='http://playerstage.sourceforge.net/gazebo/xmlschema/#params'>  <param:Global>    <pause>false</pause>  </param:Global>  <model:ObserverCam>    <id>userCam0</id>    <xyz>-2.218 -1.478 3.001</xyz>    <rpy>-0 31 36</rpy>    <imageSize>640 480</imageSize>  </model:ObserverCam>  <model:LightSource>    <id>light1</id>    <xyz>50 50 100</xyz>  </model:LightSource>  <model:GroundPlane>    <id>ground1</id>    <textureFile>grid.ppm</textureFile>  </model:GroundPlane>  <model:AvatarHeli>    <id>robot1</id>    <xyz>0 0 1.00</xyz>    <rpy>0 0 0</rpy>    <skinFile>heli_withlaser.3ds</skinFile>    <skinScale>0.003 0.003 0.003</skinScale>    <skinXyz>-0.10 0.10 -0.10</skinXyz>    <skinRpy>0 0 180</skinRpy>    <model:MonoCam>      <id>camera1</id>      <xyz>0 0 0</xyz>      <rpy>0 90 0</rpy>    </model:MonoCam>  </model:AvatarHeli></gz:world>