Using Edit Geometry Commands

The feature line geometry editing commands provided by Civil 3D are as follows:

Insert PIUse this command to insert a new PI at a point you specify. A PI can be edited in all three dimensions.

Delete PIUse this command to remove PIs from the feature line.

BreakUse this command to break one feature line into two feature lines. You can do this by creating a gap between the two feature lines, or you can have them meet end to end.

TrimUse this command to shorten a feature line by making it end precisely at another object.

JoinUse this command to join two or more feature lines to make one feature line. If there is a gap between the two feature lines, it must lie within a certain tolerance or they will not be joined.

ReverseUse this command to change the direction of the feature line. This swaps the beginning and ending points as well as reverses the direction of stationing. This can affect editing and labeling.

Edit CurveUse this command to change the radius of a feature line curve.

FilletUse this command to add a feature line curve where there is currently a PI. The command includes options to set the radius of the curve and to create multiple fillets at once.

Fit CurveUse this command to replace a series of line segments with an arc. This helps to simplify the feature line by replacing multiple points with an arc. This command differs from the Smooth command because you can control where curves are created. Also, the curves that it creates are static, meaning that they do not change when adjacent geometry changes.

SmoothUse this command to replace PIs with curves. This command is different from the Fit Curve command because it creates curves for the entire feature line and the curves are dynamic, meaning they remain tangent as the feature line is modified.

WeedUse this command to simplify a feature line by reducing the number of vertices. The command includes several options for determining which vertices to remove.

Stepped OffsetThis command creates a new feature line that is parallel to another. The command includes several options for determining the elevations of the new feature line.

To practice using geometry editing commands to make changes in your drawing, complete these steps:

The Exercise File can be downloaded at the end of the article  

1. Open the drawing named Editing Feature Line Geometry.dwg located in the Chapter 17 class data folder. In this drawing, two more feature lines have been added for lot 26. You’ll begin by adding more PIs and a curve to the back of lot 26.

2. Click the green feature line. If the Edit Geometry panel is not visible, click Edit Geometry on the ribbon.

3. Click Insert PI. When you’re prompted to specify a point, use the Center object snap to select the center of the blue circle. You will be prompted to specify an elevation.
4. On the command line, type S and press Enter to invoke the Surface option. The Select Surface dialog box will open.
5. Verify that EG is selected and click OK.
6. Press Enter to accept the elevation shown on the command line. You will be prompted to specify the next point.
7. Use the Center object snap to select the center of the red circle. You will be prompted to specify an elevation.
8. On the command line, type S and press Enter to invoke the Surface option. Press Enter again to accept the surface elevation. Additional PIs have been added, but you still need to address the missing curve.

9. Press Esc twice to clear the previous command. Click the green feature line, and then click Fit Curve on the ribbon. You are prompted to specify a point.
10. At the command line, type P and press Enter to invoke the Points option. You are prompted to specify the start point.
11. Use the Center object snap to select the center of the blue circle.
12. Use the Center object snap to select the center of the red circle. Press Esc twice to end the command and clear the selection. A curve is added to match the geometry of the back lot line. Next, you will break the feature line for lot 25 and join it to the feature line for lot 26.

13. Click any feature line in the drawing, and then click Break on the ribbon. You are prompted to select an object to break.
14. Click the blue perimeter feature line for lot 25. You are prompted to specify a second break point.
15. Type F and press Enter to invoke the First point option.
16. Use the Endpoint object snap to select the back corner where lots 25 and 26 meet. You are prompted to select the second break point.
17. Repeat the previous step to select the same point again. Press Esc twice to end the command and clear the selection. The drawing does not appear different, but the blue feature line has been broken into two feature lines.

Tips:By choosing the same location for the first and second point, you break the feature line without creating a gap.


18. Click the blue feature line at the back of lot 25, and then click Join on the ribbon.
19. Click the green feature line. The green changes to blue, indicating that the feature lines are joined to create a single feature line (see Figure 17.5).

    Figure 17.5  The result of editing the feature lines in this exercise.

Editing Feature Lines

• Using Edit Geometry Commands
• Using Edit Elevation Commands

Download Exercise File :

• Editing Feature Lines - Metric     --- ( 4.6 MB )
• Editing Feature Lines - Imperial  --- ( 5.69 MB )