Piping > Routing > Routing with Extend > About Routing with Extend
  
About Routing with Extend
You can route a new pipe segment by extending the segment in a selected direction. To extend a pipe segment, use one of the following reference coordinate systems:
Any coordinate system in the active assembly or any other assembly
The global coordinate system in the active assembly
The routing coordinate system
By default, piping uses the reference coordinate system that was used for the previous extend operation in the active assembly. If an extend operation was not performed earlier in the active assembly, the global coordinate system is used by default.