xacro.py generates empty urdf file
I am using following command to convert *.urdf.xacro to *.urdf in ROS indigo,ubuntu 14.04:
rosrun xacro xacro.py a.urdf.xacro > a.urdf
also
rosrun xacro xacro.py -o a.urdf a.urdf.xacro
content of a.urdf.xacro(just for test):
<?xml version="1.0"?>
<robot xmlns:xacro="http://www.ros.org/wiki/xacro">
<property name="base_mass" value="3.7000" />
<xacro:macro name="hunter">
<xacro:macro name="hunter_robot" >
<link name="base_link" />
</xacro:macro>
</xacro:macro>
</robot>
and the content of generated urdf:
<?xml version="1.0" ?>
<!-- =================================================================================== -->
<!-- | This document was autogenerated by xacro from a.urdf.xacro | -->
<!-- | EDITING THIS FILE BY HAND IS NOT RECOMMENDED | -->
<!-- =================================================================================== -->
<robot xmlns:xacro="http://www.ros.org/wiki/xacro">
</robot>
I have faced this problem in two different machines. any idea?