Specifies whether hidden lines are shown and whether they are shown for piping only or for all plant objects.
Access Methods
Ribbon: Ortho Editor tab 
Output Appearance panel Hidden Line Piping
Command entry:
plantorthohiddenlinemode
List of Prompts
Specify the display mode for hidden lines when creating Ortho drawings [Nohiddenlines/hiddenPipingonly/Allhiddenlines]:
Nohiddenlines
Pipes behind other pipes are hidden.
hiddenPipingonly
All pipe lines show (default).
Allhiddenlines
All pipe lines and other objects behind pipes or objects show.
