Assigning Feature Line Elevations - Part 2

In this exercise, you will assign elevations to the feature lines you created from AutoCAD lines in the previous exercise.

Edit feature line elevations

Note:
This exercise uses Grading-2.dwg with the modifications you made in the previous exercise (Part 1).
1. Click Modify tab Edit Elevations panel Elevation Editor  Find.
2. Click the feature line that stretches from circles C, D, E, to F.
   In the Grading Elevation Editor, you see the length of each segment and elevations at each vertex. The elevation of the first point is 688.000 (from Part 1) and the elevation of the last point matches the elevation of the surface. The elevation values of the two intermediate points are automatically interpolated based on the beginning and end-point values. You can use this table to edit the elevation and grade values. Now you will assign elevation values to line AB.
3. Click , and then click the feature line between circles A and B. The Grading Elevation Editor now displays the elevations along the feature line between circles A and B.
4. Double-click the elevation value for the starting station (0+00.00), and change it to 630.00’. This value puts it a few feet below the surface. Change the elevation of the end point to 690.00’.
   In the next few steps, you will insert an elevation point on the feature line.

Insert an elevation point on a feature line

1. In the Grading Elevation Editor, click  (Insert Elevation Point).
   On feature line AB, you see a small circle and a tooltip that shows the station value and elevation of the point. You can use the cursor to move this point to a new location.
2. Move the point to a location near the middle of the feature line, then click.
3. In the Insert PVI dialog box, optionally move the elevation point to a specific station. Click OK.
   The point is added to the table in the Grading Elevation Editor, where you can edit the station, elevation, grade, and length (distance between points).
4. Click feature line AB.
   Editing grips are displayed for the endpoints and elevation point. You can click the elevation point and slide it along the feature line. You can also click one of the endpoints and move it to a new location. When you do any grip editing, values in the Grading Elevation Editor update.
5. Move the cursor over the surface near the elevation point to see the surface elevation displayed.
   
6. In the Grading Elevation Editor, set the elevation point to an elevation that is at or below the surrounding surface.
   In the next few steps, you will drape feature line BC across the existing ground surface. This command assigns an elevation to each vertex of the feature line.

Drape a feature line on a surface

1. If necessary, press Esc once or twice to deselect feature line AB.
2. Click Modify tab Edit Elevations panel Elevations From Surface  Find.
3. In the Set Elevations From Surface dialog box, ensure that Insert Intermediate Grade Break Points is selected and that Relative Elevation To Surface is cleared. click OK.
4. Click feature line BC, then right-click and click Enter to end the command.
5. Click feature line BC again. An elevation point has been added wherever the line crosses the edge of a triangle in the TIN surface.
6. Right click and click Elevation Editor.
   The Elevation Editor displays data for each elevation point along feature line BC, including its elevation, and the distance and grade to the next point. A feature line on the surface like this can be a useful starting point for a grading. You can use controls along the top of the Grading Elevation Editor to add and delete elevation points, and to adjust their elevations. You can select multiple points within the table for group operations, such as raising or lowering them the same amount, or “flattening” their elevations to the same value.
7. Click  to close the Grading Elevation Editor.