Creating Feature Lines

Civil 3D provides a comprehensive set of tools for creating feature lines. They can be drawn “from scratch,” by converting an AutoCAD® polyline, or by extracting them from more complex Civil 3D objects such as corridors or profiles. When drawing a feature line from scratch, you must provide the elevation of each PI. For all other methods, the elevations are obtained from the object that you have selected.

To use feature lines in your drawing to begin designing some lot grading, follow these steps:

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

1. Open the drawing named Creating Feature Lines.dwg located in the Chapter 17 class data folder. This drawing is zoomed in to lot 25 in the top-right and bottom-right viewports. You’ll also notice that the corridor layer has been thawed to reveal the road corridor.

2. On the Home tab of the ribbon, click Feature LineCreate Feature Line From Corridor. You will be prompted on the command line to select a corridor feature line.
3. In either the top-right or bottom-right viewport, click the edge of the corridor that aligns with the front of lot 25. The Create Feature Line From Corridor dialog box opens.
4. Verify that Site is set to Lot Grading. For Style, select Lot Grading – ROW, and then click OK. The new feature line will be displayed as a thick red line.

   Tips:Note the Create Dynamic Link To Corridor option. If the corridor is modified, this feature line will respond to match the new design.


5. Press Esc to end the previous command. On the Home tab of the ribbon, click Feature LineCreate Feature Line. The Create Feature Lines dialog box opens.
6. For Style, select Lot Grading and then click OK. You are prompted to specify the start point.
7. In the top-right viewport, use the Center object snap to select the center of the red circle at the north corner of lot 25.
8. When you’re prompted to specify an elevation, press Enter. You will then be prompted to specify the next point.

   Tips:Although 0.000 is listed as the elevation, feature line interaction will match this feature line to the corridor feature line at this location.

9. In the top-right viewport, use the Endpoint object snap to pick the west corner of lot 25. You will be prompted to specify the elevation.
10. At the command line, click SUrface to invoke the SUrface option. The Select Surface dialog box will open.
11. Verify that EG is selected and click OK. The default elevation on the command line becomes 190.059 (57.930), which is the elevation of the EG surface at the corner of the lot.
12. Press Enter to accept the elevation. You are prompted to specify the next point.
13. At the command line, click Arc to invoke the Arc option. You are prompted to specify the arc endpoint.
14. At the command line, click Secondpoint to invoke the Secondpnt option. You are prompted to specify the second point.
15. In the top-right viewport, use the Nearest object snap to select a point along the back line of lot 25. You are then prompted to select the endpoint of the arc.
16. In the top-right viewport, use the Endpoint object snap to select the south corner of lot 25. You are then prompted to specify the elevation.
17. At the command line, click SUrface and press Enter to accept the default elevation of 190.456 (58.027). You are prompted to specify an arc endpoint.
18. At the command line, click Line. You are prompted to specify the next point.
19. In the top-right viewport, use the Center object snap to pick the circle at the east corner of lot 25.
20. When prompted to specify the elevation, press Enter.
21. Press Esc to end the command. You have drawn a feature line that matches the edge of the corridor at the front of the lot and EG elevations at the back lot corners.

22. On the Home tab of the ribbon, click Feature LineCreate Feature Lines From Objects. You are prompted to select an object.
23. Click the rectangle at the center of lot 25 and press Enter. The Create Feature Lines dialog box opens
24. Check the box next to Style and select Lot Grading. Click OK. The feature line is created, but it is located at elevation zero. If you zoom out in the lower-right viewport, you will see the blue rectangle at the location of the lot label and parcel lines.

Download Exercise File :

• C17 - Creating Feature Lines - Metric     --- ( 2.31 MB )
• C17 - Creating Feature Lines - Imperial  --- ( 2.82 MB )