formation models

Working on a formation model for a new housing development. It can be a bit of a ball ache and anyone who tells you its a simple quick process is either lying or hasnt done it properly. "You've got the cad drawing it gives you this!!", well not quite.... It gives you a good start. Its not just a case of applying a surface depth to each surface oh no that would be too easy. What if the road is adoptable? If the road is 6m wide, the dig isnt 6m, oh no its proportional to the surface depth. It could be that the "box" for a 6m wide road is actually 8m. The excavation for a 1500 diameter manhole is near on 2.5m x 2.5m x its depth. This is where LSS comes in, but even then theres a lot of manipulation to do.