I assume you are looking for information on the OpenRoads tools provided in MX v8i SS3, if not do let me know.
There is information on the community site at the link below which is helpful for those starting out with the OpenRoads tools.
OpenRoads Support Clips, TechNotes & FAQs
The Terrain Create From File will allow you to convert an MX model to a terrain model (similar to a triangulation model in MX). For CAD survey files you can use Create Terrain by Graphical filter which is similar to the MX CAD Data Import function.