Ground control polygons and "Impervious Proposed" Polygons provide respective custom grading over areas of the site. They are especially useful for providing detailed grading either overlaying existing parcels, or, for commercial and multi-family sites for controlling grade in certain areas.
Impervious Surfaces have additional behaviours:
Area added into schedule of quantities (based on 'FINISH')
Sub- surface depths factored in for cut-fill
Select Grading -> Ground Control and draw a polygon for the area to add ground control grading control.
Select Grading -> Impervious and draw a polygon for the area to add impervious layer and grading.
You can have multiple overlapping ground control areas (i.e. larger area with a max grade restriction then a smaller area with a max elevation restriction).
⚠️ Overlapping impervious layers can result in double counting of areas in scheduling.
Settings
Grading parameters can be added to the ground control polygon.
Setting | Description |
Max Cut / Fill | Define the maximum amount of cut or fill allowed for the parcel. You can set a negative value (for example a -1 foot cut on the site will mean at least 1 foot of fill used on the parcel). Common uses for this are: - Prevent excavation of ground with potential artifacts. - Avoid cutting where there is existing underground infrastructure (ie an underground gas pipe) |
Min/Max Grade | Sets the grade tolerance for the parcel. Note - if parcel has a building on it then other grade parameters from the web Lot settings will additionally define grade on parts of the lot (building fallaway, front, rear lot grades) |
Min / Max Elevation | Allow you to specify a parcel to be above a certain elevation. Some common uses for this are: - to keep out of a flood zone - to ensure parcel is elevated for views. |
Drain to road | If enabled, will ensure the polygon grades to the closest road. |
Smooth | If enabled, smooths the area (ie forces it to be graded), if disabled, will only touch the ground to meet grading controls. |
Allow Depression | If enabled, allows the ground polygon to fill with water in a 100 year flood event |
Finish (Impervious only) | Used to schedule the quantity of impervious surface |
Sub Assembly | Specify a sidewalk / lane subassembly and it will use the depths of each layer to assist with cutfill calcs for that specified area. |