You construct a grading projection from feature lines. As shown in figure 7, the controlling feature line to which a grading is attached is called the footprint. You can edit this feature using the feature line commands. The grading projection creates another line at the outer edge, known as a daylight line. Depending on the grading criteria, the daylight can be at a specified elevation, distance, or where the grading meets the existing surface. The daylight line is controlled by the grading object and cannot be edited directly.
Figure 7: Parts of a grading object, shown on a 3D solid
Projection lines connect the footprint to the daylight line at key design points, such as the start and end of transitions. These projection lines are created with non-editable feature lines. Grading styles have a 3D solid display component that shades the surface and displays automatically in a 3D view. This can be used to view the grading without creating a terrain model.