Expand an arm and click Levels in the left hand pane. The Blend Point page is displayed.
By default, AutoCAD Civil 3D 2017 takes the arm elevation and longitudinal gradient at the Deviation Point from the existing surface. To specify a different level or gradient, select User Defined Elevation and Grade from Take Elevation and Grade From drop-down list and enter the required values in Elevation and Grade. Grade is measured towards the roundabout and a positive gradient is increasing level.
Vertical Transition Arc is a user defined arc of given radius where one end of which is tangential to the incoming road.
In all cases the Max and Min values represent the limiting values from the adopted design standard.