Use this procedure to merge geometry into a 2D elevation. When you merge linework into an elevation, you assign additional linework to a display component of an elevation. Use this feature when you want to add detail, or add linework that you did not model.
You can also click (Match existing linework) and select linework in the elevation whose display component you want to match.
The linework is merged into the 2D elevation. When you select the elevation, the linework is selected with it.