Reference Coordinate System
Set reference CS for isometries
Plant Engineering > Isometry / Pipe Spool Drawing > Set reference CS for isometry 
Normally, the world CS of the layout plan is used to determine coordinates in isometric drawings. You can however define the local coordinate system of the layout plan as the reference coordination for isometric drawings.
To do this, a local coordinate system must exist for the layout plan, if this is not the case, HiCAD will prompt you to Define a local coordinate system.
Clicking 
below the function opens a pull-down menu with the Delete reference coordinate system for isometry function.
This function can also be applied to pipe spool drawings.
Delete reference CS for isometries
Plant Engineering > Isometry / Pipe Spool Drawing > Ref. > Delete reference CS for isometry 
If you have previously defined the local coordinate system of the layout plan as the reference CS for the isometry,and then execute this function, the World CS of the layout plan will again be recognised as the reference CS for isometric drawings.
This function can also be applied to pipe spool drawings.
Isometry and Pipe Spool Drawing (PE/Iso) • Isometry and Pipe Spool Drawing Functions for the Layout Plan (PE) • Plant Engineering Functions • Local Coordinate System (PE)