This command can be used to SET Surface that this STRUCTURE part references and  to SET Alignment that this STRUCTURE part references.  

STRUCTURE a very important component of the program Autodesk® Civil 3D®, so if we have a large number of  STRUCTURE

When creating a PIPE network without defining its Alignment reference or Surface reference, each STRUCTURE will not have Alignment reference or Surface reference.

You need to define STRUCTURE Alignment reference or Surface reference in order to display information about STRUCTURE correctly. Or, each STRUCTURE Alignment reference or Surface reference can be changed if necessary.

So we want to SET Surface that this STRUCTURE part references from a single command without having to repeat the command, and also we want to SET Alignment that this STRUCTURE part references.

This is also possible with an alternative command.