The Model Data > Model Topology > Add Pipe (also referred to as Add Conduit) function allows graphically the addition of a pipe (also referred to as conduit) to the existing system model. Note the above menu item is not yet implemented.
Alternatively, click on the 
Add Pipe toolbar button to access the above function.
This launches the Quick Draw function with which pipes can be added to existing nodes or created from scratch.
There are three different drawing modes, viz. Single, Connected and Multi-Segment modes:
•The Single mode (leftmost option) in which each left-click with the mouse represents the placement of a junction (i.e. most basic structure type), and after two such left-clicks a straight pipe between the two junctions is created.
•Multi-Segment mode (rightmost option), in which the first left-click either selects or creates the first junction, and subsequent left-clicks create only vertices on the pipe, until the last left-click which will be the second junction of the pipe if followed by a right-click.
•Connected mode (middle option). Here every left-click represents a junction whereby multiple, connected straight pipes can be captured until the process is stopped by a right-click.