HOW TO STATION A 3D ALIGNMENT

Does anyone out there know how to station a 3D alignment using InRoads or OpenRoads tools?

Typically, we station alignments beginning with an alignment within a 2D plane. But, I have found that long linear oil/gas projects use 3D stationing based upon ground distances along a profile, rather than just along the x-axis. The examples I have seen show both the 2D stationing as well as "3D" stationing.

Any simple straight-forward ideas on how to do this would be helpful.

Thanks. MJM