Here's an example (attached picture). The house walls (foundation and subgrade shown) are extended stepped down to meet existing grades. There's also retaining walls at the existing upslope and where fill for driveway was added. In this case I did not try to join the "fill" element to the rest of the mesh. That might be a good idea at some later point in project when modeling is done.
oops "simulate" π
Untitled - 1.png