Expand Roundel and click Levels & Grades in the left hand pane. The Levels & Grades page is displayed.
By default, the roundabout Elevation is set to Existing Surface as defined on the General tab. To specify a fixed level for the roundabout, select User-Defined Elevation and enter the Elevation at Center.
It is good practice to build roundabouts with an overall cross slope, i.e. on a tilted plane. Select Has Overall Cross Slope to build the roundabout on a tilted plane and enter the cross slope, as a percentage, in Overall Cross Slope.
By default, Autodesk Civil 3D 2025 creates cross slope towards the lowest point on the existing surface at the ICD. To specify a different cross slope direction, clear Fall Towards Lowest Point on ICD and enter the required direction, as a whole circle bearing, in Overall Cross Slope Direction.
In all cases the Max and Min values represent the limiting values from the adopted design standard.
You may enter required cross slopes for the Apron and up to two circulatory crown lines, that is, the Apron to Secondary Crown, the Primary to Secondary Crown and the Crown to ICD. In all cases the slope is positive if it falls towards the ICD.