In addition to taking over flow direction from P&ID when assigning pipelines, Smap3D Piping provides the ability to set (and control) flow direction for individual pipelines (pipeline paths) manually.
The flow direction of the pipeline paths can be used especially within the subsequently used applications Smap3D Isometric and Smap3D PCFExport.
In terms of Smap3D Piping, flow direction defines the order of components within the tree view. When a flow direction is set, the components are always sorted from the pipeline input to pipeline end.
The flow direction control commands are available under Flow direction within the context menu displayed for a pipeline path (in the Smap3D Piping tree view) and are following.
If a pipeline path has not specified any flow direction, this command is available.
When it is started, a red sphere appears on one of the pipeline ends. This indicates the start point (input) of the pipeline.
The start point can be swapped from one pipeline end to the other using Swap flow direction available in the Set Flow Direction dialog.
When the flow direction is confirmed (OK),
the pipeline within the Piping tree view gets new symbol 
indicating directed pipelines.
This command allows the user to remove flow direction of a directed pipeline.
When it is processed the pipeline gets the symbol 
indicating undirected pipelines.
This command serves to flip the flow direction (it swaps the pipeline's input and output).
When this command is used, a 3D arrow pointing in the flow direction is displayed at the pipeline input.
The Hide flow direction command hides the 3D arrow displayed using the Show flow direction.