by Graham Riddleston
One of the most powerful features of Civil 3D is the ability to create offset alignments. Offset alignments contain most of the intelligence of regular alignments (e.g. profiles and corridors can be created from the) but they are permanently linked to their source alignments. This means that if the source alignment is edited, the offset alignment’s relationship will be maintained. Offset alignments can also be used to create regions of widening and tapering.
To read more download the whitepaper: