Technical information

124 | Chapter 9 Using Grading Commands
Overview of Grading
When you add or remove soil, rock, and other materials to shape the land for
a project, you generally develop a grading plan to indicate how the finished
surface appears. The grading tools enable you to model the existing and pro-
posed ground surfaces and analyze the design.
After you develop a grading plan, you can then create a proposed surface
model. You can use the surface model to analyze a site efficiently and
accurately and to create reports, graphics, and 3D presentation materials that
are necessary for the completion of the project.
When you use the finished ground model, you can do the following:
■ Calculate cut and fill volumes
■ Determine grading limits
■ Generate proposed grade and cut and fill contours
■ Calculate the watershed areas for the surface
■ Create post-development runoff models
Finished Ground Data
An existing ground surface is generally based on surveyed points and existing
contours, whereas a finished ground surface is based on grading data that
you create. One goal is to create enough grading data, such as points,
3D polylines, contours, pond models, daylight lines, and breaklines, so that
the finished ground surface is as accurate as possible.
AutoCAD Land Desktop includes several commands that you can use to
create grading data, including points, contours, and 3D polylines.
Using the civil engineering tools you can create the following grading data:
■ Grading objects: Provides a fast, efficient 3D modeling tool that
accurately represents such design elements as roadways, embankments,
parking areas, excavations, or ponds. For more information about grading
objects, see “Creating a Grading Object” on page 126.
■ Daylight points, lines, and breaklines: Elevational points and breaklines
can be generated to represent daylight slopes. You can draw a resultant
daylight polyline to connect the daylight points. The daylight polyline is
a 3D polyline that represents the match line of the slopes to the surface.
It can be used as a breakline and a border in surface definition. It can also
be used to represent a work limit line.