Utility Data- Surfaces

Hello all,

My ultimate goal is to model utility information on profiles. I know utility data can be stored as a surface file or within a .stb file. Which method is more functional? Especially in terms of modeling boxes for duct banks and also modifying elevation information once the utility is created? Thanks in advance,

MicroStation V8i (SELECTseries 3) - V08.11.09.459

InRoads Suite V8i (SELECTseries 3) - V08.11.09.493