Lot Lines

Traditionally, lot lines are thought of as 2D representations of parcels. However, in Autodesk Civil 3D, lot lines can also have elevations and can be used in building a grading model. Feature line editing commands are used to assign elevations, including elevations at intermediate points. Lot lines interact with feature lines, sharing elevations at common points. They can also be added to surfaces as breaklines. When you display the lot lines, you can use the elevations of the objects or you can flatten the elevations to a specific elevation. This option is available in Site Properties.

It is not always desirable to use lot lines directly for grading work. Inserting elevation points, or intersecting feature lines with lot lines creates break points in the lot line geometry, which affects labels. A lot line crossed by a feature line is split into two segments with separate labels. On a small site, you could use a mix of lot lines and feature lines in your grading site, ignoring the parcels that are created.

Preventing Lot Line Interaction

Provide greater clarity in a grading design by preventing the interaction of lot lines with feature lines, using separate sites for parcel geometry and grading features. One approach is to replace the lot lines with feature lines in the grading site. There are several methods for doing this:

• If you create the lot lines from AutoCAD entities, use the same entities to create feature lines in the grading site.
• Copy the lot lines to the grading site, and then explode these lot lines, turning them into AutoCAD entities. Then, use grading tools to convert some or all of the lot lines into feature lines.
• For a small site, trace the lot lines with AutoCAD entities to convert to feature lines, or use the Draw Feature Line command.