Editing Surface in Civil 3D

[Fullalove]

I've got an existing surface created in Civil 3D and I now need to depict a new surface, which will include an excavation for some building foundations. I am relatively new to the program and am having a very difficult time determining how to show this new surface. I know the dimensions and depth of these excavated pits but cannot get the program to create a new surface that reflects these future digs. Any advice?

[rustysilo]

You will likely want to look into feature lines for this. Draw feature lines depicting your foundation. Create a surface and add the feature lines to the surface as breaklines.

[Fullalove]

Thanks, I'm well on my way en lieu of that advice, however, is it possible to change the grading style that is automatically implemented when pasting one surface into another. What I am attempting to do is create a basement footprint into an existing surface in such a way that the drop from existing surface to basement surface is abrupt. What I am getting instead is a gradual, very shallow grade from the basement surface up to the existing surface. Any advice?
Thanks

[BIGAL]

You can chnage the batter slope to a small value say 1 : 0.001

Alternativel create 2 polylines and set the elvation to basement level the second slighty offset 1mm if metric and make its elevation well above the surface make a new surface model (defintiom autocad objects)

The simply add a third surface copy and paste natural to this 3rd surface then copy and paste 2nd surface you should have now have what you want