CADWorx Plant I tab: Stop Sign 
Misc toolbar: Stop Sign
Command line: STOPSIGN
Places stop sign symbols in the drawing. This symbol is used for designating the starting and ending locations for automatically-generated isometric output. For more information, see Isogen Out. Stop signs must be at a weld or connection point on the piping system. You place these designators on the drawing and then export them to the database. This could occur manually with Export Pipe or automatically with Setup Live Database.
If stop signs are present when using the Database option of the ISOOUT command, you are asked if stop signs should be used in generating the ISOs.
Use Stop Signs [Yes/No] <Yes>:
If you select Yes, continuity is checked and the ISOs are broken at each stop sign. If there are no line numbers or stop signs present in the database, the following prompt displays.
Database does not have any line number or stop signs...
When exporting with the Select Isogen Style dialog box isometric generator (Isogen Out or Isogen Batch), stop signs are used, if selected.