You will need to construct at least 2 surface models to compute volumes. It seems you need to learn a bit more about the software before attempting to use it. I recommend you at least go through the tutorials on surfaces, gradings and corridors. See the Help pull down to access the tutorials.
Neil Wilson (a.k.a. neilw) Infrastructure Suite/C3D 2013, LDT 2004, Power Civil v8i SS1 WIN 7 64 PRO HP Pavillion h8xt, i7 2600, 12 GB RADEON 6450, 1 GB http://www.sec-landmgt.com