Your surface should be triangulated (Surface>Triangulate) prior to be saved in DTM format (File>Save>surface).
Lateron you can open the surface (File>open & select file type as DTM) and modify it.
To view the surface points, just use Surface>View Surface>Features. It will bring a dialog box to select which points you want to view.
Hope it helps.
I need helpful hints with the 3-D issue. Once the surface is loaded what is the steps for getting a 3-D model? Can it be accomplished with the DTM file??
joeeit,
Once you load DTM file, you can display the triangles into your Microstation or autocad file by using Surface>View Surface>Triangles.
Once the triangles have written to your CAD file, you can render the triangles using standard 3-d display routines of the Cad software.
Its simple and looks good on screen, provided the data loaded is correct.