A grade break informs Level AI where a split can be added into the model, this can either be a slope with a grade or a wall. Whether it is a wall or a slope depends on the grade break settings. Wall setting default values are inherited from the projects web settings. Level AI will put a slope if the parameters (height, width) allow, if there would be a clash with another object (i.e. a pond, building, other grade break, road, earthworks extent) it will flip to a wall.
Grade breaks can be manually drawn, or added from the automatically generated "Potential Grade Breaks" after a Level AI run.
Drawing a Grade Break
Select "Grade Break" from the Grading Draw/Convert menu, you can now customize settings for the grade break.
Grade Break Default Settings
Default settings are configured in the web, these are initialized on project creation from a close project / specific client project and can be subsequently updated. Default settings apply to all walls when they are created in Civil 3D.
Grade Break Settings
Setting | Description |
Max Height | Maximum height the grade break can be. |
Max Batter Grade | Batter / Slope maximum grade |
Max Batter Width | Maximum width before grade break flips to a wall. |
Min Height Left | This should only be used for things like truck-bays where the direction of the grade break matters. For this type of grade break, it specifies a minimum allowed height of the wall in the 'left' direction (line style indicates which side of wall is 'left'.
Leave blank in most cases. |
For example if maximum height is 6ft, batter grade is 33% and maximum width is 9ft, then if Level AI sizes grade break up to 3ft in height grade break will be a slope, and anything between 3-6ft will be a wall.
If the webapp settings have Retaining walls allowed deselected, then maximum batter width will dynamically be updated to Max Height / Max Batter Grade. The grade break will still flip to a wall if there is not room for the desired slope.
Potential Grade Breaks
On a parcel you can configure the vehicle crossing placement and width on each Parcel Object. Alternatively driveway crossings can be specified by drawing an Impervious feature and setting the type to DRIVEWAY. The Level AI run settings additionally allow you to specify where potential walls should be placed on your site (wrapping parcels, roads and road frontage).
Potential walls are then automatically generated in a Level AI run. After results have been processed from a what-if mode you can automatically add the potential walls to the model. More information on converting potential grade breaks to grade breaks is found here.