A grading object normally consists of the footprint, the daylight line, the projection lines, and the face.
The face is the area bounded by the lines that define the grading. It is marked with a center marker .
Plan view of grading object
The footprint can be an open or closed figure. The footprint must be either a feature line , a lot line, or the resulting daylight line of another grading.
A feature line is a line that represents some important feature in the drawing, such as a ridge line or the bottom of a swale. A feature line can be drawn with the Draw Feature Line command, or created from 2D and 3D polylines, lines, and arcs. You can also export feature lines from corridor models.
The target for the grading can be a surface, a distance, an elevation, or a relative elevation.