Terrain object has next properties:

The shape of a terrain is defined by defining a boundary After starting the terrain, the outer shape (boundary) is entered by drawing a polyline Contour lines (isolines) are drawn as lines assigned with elevation. Isolines are automatically lengthened up to the outer contour's boundary or are cut off at this boundary Contour lines can also be closed. User can edit contour lines by starting the terrain's Intelligence dialog The contour lines are shown in a list in the dialog box, and can be selected accordingly Import of DXF lines supported. User can set quality of terrain’s geometry to optimize it or set high 3d resolution