Saving your houses or other structures as 3D symbols allows you to place multiple buildings in a single plan to create 3D views of an entire neighborhood, subdivision, or lot with multiple structures.
Create a plot plan polyline by inputing distance and angles into the New CAD Line dialog, then convert the polyline to a terrain perimeter.
Before you can use the terrain tools to create terrain objects, you must add a terrain perimeter to the drawing, and then be on that floor to add terrain objects.