2018-05-08 - Vijay Pradeep:

These visual/ mesh files were generated from the dae files in
ros-industrial universal robot repo [1]. Since the collada pyBullet
parser is somewhat limited, it is unable to parse the UR collada mesh
files.  This, we imported these collada files into blender and
converted them into STL files.  We lost material definitions during
the conversion, but that's ok.

The URDF was generated by running the xacro xml preprocessor on the
URDF included in the ur_description repo already mentioned here.
Additional manual tweaking was required to update resource paths and
to remove errors caused by missing inertia elements.  Varios Gazebo
plugin tags were also removed.

[1] - https://github.com/ros-industrial/universal_robot/tree/kinetic-devel/ur_description/meshes/ur5/visual