Ok I duno much about Civil field as I am from Mechanical side. But Autocad is the worst cad package I have seen for 3d. Actually 3D designing is very easy even much easier than 2d but autocad is exception.
As i told you i duno much abt the field but I have heard about two popular cad softwares for arch
1. Autodesk Revit Architecture
You must have heard about 3DS Max (General purpose 3d graphics and animation software). It is used for demonstration purposes only by architects( means to quickly create 3d concept designs for clients)