Centralizing URDF packages about urdfdom

[isucan]

urdf_parser and urdf_interface were deprecated in ROS Groovy. They have been removed in ROS Hydro.
We now have urdf, urdfdom and urdfdom_headers.

urdfdom_headers is a library containing just header files for the data structures of a parsed URDF. urdfdom is a library that populates such datastructures by parsing URDF files.

Additionally, we now have urdf_parser_plugin, which provides a simple interface (a parse function) for parsers to fill the datastructures mentioned above. So urdfdom is used to trivially implement such a parse function.
The advantage of having this abstract interface is that we can use other parsers too. For example, collada_urdf can provide the same plugin interface and parse collada files in order to fill in the same URDF datastructures.
Because these are plugins, we need not link against all parser libraries. So we will not be yet again delayed in releasing packages for distros where the collada debs are missing.

urdf is a ROS package that uses collada_urdf and urdfdom (actually, plugin intefaces) to parse different types of files, using different parsers, into the same datastructures in urdf_headers.

[davetcoleman]

Above you said collada_urdf but it should be collada_parser if i'm not mistaken

[isucan]

yes, collada_parser. sorry about that.

[davetcoleman]

I've done my best to document what you just said here: http://www.ros.org/wiki/urdf#Components