`When a DWG is converted to Allsite any existing Civil 3D parcels get Allsite extended data automatically applied, this includes lot grade information and other data for both Service AI and Level AI to run.
Sometimes tiny parcels are automatically created in road corridors. Use the Toolspace to find and remove these.
Default parcel settings (configured in the web)
When parcels are converted to Allsite they inherit default lot settings from their linked Allsite.ai project (you can see all Level AI settings on the web or via the Settings button in the Civil 3D Allsite ribbon). These settings define the initial values for things such as parcel lot grades and lot typology. See below for more information on different Normal lot sub types. They also define the behaviour of the lot system to grades, such as protective slopes, driveway and rear yard grades.
Lot grade settings are only applied to lots that have a building on them and have been set to NORMAL lot category with a SINGLE FAMILY lot typology.
Default grades
This table define the lot typology and grades for different lot category. See here for more details on lot typology.
Setting | Description |
Default minimum grade (%) | Project-wide default absolute minimum (drainage) grade applied to lots / areas unless overridden per parcel (see Min/Max Grade under Parcel Settings). Default 0.5%. |
Default maximum grade (%) | Project-wide default absolute maximum grade applied to lots / areas unless overridden per parcel. Default 33%. |
Protective Slopes
This defines the graded surface immediately surrounding a building platform, designed to direct runoff away from the building and out of the lot. Feature lines are automatically added defining the shape of the flow lines / swales. These are only relevant for single family NORMAL lot typology when a building is on the parcel.
Protective slopes are only added to model if the protective slope distance is such that the protective slope intersects with the edge of the parcel (ie flow line).
Setting | Description |
Flow line slope comfort (%) Flow line min / max grade (%)
| Target and limits for grades of the swale / flow line collecting run-off from the building and taking it out of the site. |
Protective slope min / max grade (%) | Minimum and maximum limits of the protective slope around building. |
Protective slope distance | Distance away from building the protective slope connects with the flow line. |
Driveway Grades
This defines the graded surface at the front NORMAL category, SINGLE FAMILY type lots. See detailed grading below for details.
Setting | Description |
Driveway max grade initial (%) | Maximum grade of the first 6.5ft of the parcel |
Driveway transition max grade change (%) | Maximum grade of the subsequent 6.5ft of the parcel |
Driveway max grade (%) | Applied to impervious DRIVEWAY type. Note, if driveways set to auto generate (refer to Layout Assist settings) this grade is applied to the driveway. |
Front/Side/Rear Yard
This defines the graded surface at the front, side and rear of NORMAL type lots. See detailed grading below for details.
Setting | Description |
Front/Side/Rear yard max slope (%) | Maximum grade of the front / side / rear yard |
Front/Side/Rear yard setback | Distance from front / side / rear of lot to apply the rear yard max slope. Also used to help place buildings for Layout Assist. |
Surface Feature Lines
Setting | Description |
Protective slope feature lines | For non-vacant lots, the locations for protective slopes (and flow lines) around the building. Can be:
Default "All" protective slope lines output. Only applies to lots with buildings that are NORMAL category and SINGLE FAMILY sub type. |
Draw vacant lot setback feature line | For vacant lots, draws a feature line at the front, rear and side setbacks provided above. This helps to provide the grade definition within surface triangulation for the given areas of the site.
By default no setback feature lines are output. Only applies to vacant lots with NORMAL category and SINGLE FAMILY sub type. |
Draw building FFL feature line | The locations for protective slopes (and flow lines) around the building. Can be:
|
NOTE:
If grade breaks are added around a parcel the protective slope feature lines are not added into the model. Future upgrades will automatically add a flow line (feature line) between building and parcel boundary/boundary wall.
Parcel Settings
Once the parcel has its Allsite extended data automatically added you can customise settings on a per parcel basis.
As all parcels are automatically assigned default category on creation (to "NORMAL" category defined in default settings), remember to change any category for PUBLIC DRAINAGE or PUBLIC PARK parcels that are not residential (ie small end parcels or parcels with detention ponds.)
Setting | Description |
Category | This defines the category of a lot. All lots need a category and the category will determine how Level AI applies grading.
NORMAL category lots can have further refinement of their grading - see 'Normal Parcel Type'.
PUBLIC DRAINAGE lot category will not have Storm / sanitary connections. Use for lots that have detention/retention in them.
PUBLIC PARK lot category does not have Storm / sanitary connections
SUPERLOT - this can be used for parcels that will be cut up later into NORMAL category lots. Superlots are ignored by Level AI (ie can overlap other parcels)
You don't need to set a PUBLIC ROAD parcel as this will automatically be created based on the road corridor. Public road parcels will have grading consistent with the crossfall of the road including daylight settings from your Assembly.
NOTE - At least 10% of parcels need to be of NORMAL category. Review comments will be added on any parcels with no category including areas where there is no parcel defined. |
Normal Parcel Sub Type | Only relevant to NORMAL category parcels. This tells Level AI the way the lot will grade. If set to 'Single Family' it will automatically determine whether lot will be Type A, B or C.
If no building on the lot set to one of the VACANT lot sub types. |
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, side lot grades) |
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) |
Drain to road | If enabled, will ensure the polygon grades to the closest road. |
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. |
Smooth | If enabled, smooths the area (ie forces it to be graded), if disabled, will only touch the ground to meet grading controls. |
Vehicle Crossing / Driveway Placement (width, location) | Configure the location of vehicle crossing (determines where potential grade breaks will be placed at the road frontage of the parcel). Location specified as High, Mid, Low - this looks at the existing surface (initial run) or the last design surface to determine location of vehicle crossing. Defaults to middle of road frontage. |
Services Connection and offset | For use with Service AI to say where it is preferrable to connect services into the parcel. If parcel should not have a connection, set to "NOT CONNECTED"
NORMAL parcels will apply the default storm / waste connection (from web) if left unset. |
Services Placement and offset | For use with Service AI to say where service lines should run within a parcel. For example if Sanitary pipes are preferred to run down the rear of a parcel, offset by 6 feet, then would set "Sanitary Placement" to REAR and "Sanitary Offset" to 6 ft. |
Subnetworks | For use with Service AI, defines the subnetwork for the storm / sanitary. If set to blank will be automatically set to subnetwork 1 if there is a respective service connection. |
Relationships (fall to vehicle crossing) | Relationship between the pad location (ie centre of parcel) and the vehicle crossing. Specified as a min/max. This ensures the location of the building is above the road at point of vehicle crossing by a set amount. |
Normal Category Lot Typology
Three different 'NORMAL category' typologies are supported for Single Family residential.
Type A - Drain to road
Type B - Split, front drains to road, back drains out back
Type C - Drain to rear
If the lot sub type is set to SINGLE FAMILY it automatically determines the type based on other grading parameters.
Single family lots have the additional grading features where building 'fallaways/protective slopes' are automatically added around the house, this ensures correct drainage.
Settings for protective slopes are described above.
More details of protective slope and lot typology:
Detailed Parcel Grading
For NORMAL category, SINGLE FAMILY type lots you can specify setbacks for side, rear and front of lot. Each area of the lot can have different grading characteristics, these are different if it is a Vacant vs Non Vacant parcel.
Vacant Parcels
For Vacant parcels, the building setbacks form a pseudo 'pad' area. This is the area remaining after the front, rear and side yard setbacks have been created. This will have a breakline in the resulting Level AI model. Note - the 'pad' area is still set with a max grade the same as that of the parcel. If you want an actual pad (ie flat area) add a building.
Non Vacant Parcels
When a building is placed on the lot and the type is set to SINGLE FAMILY a protective slope is added (see above for protective slope grade and size settings). The front and rear yard grades will have priority over the protective slope grade, but the protective slope has priority over the side yard slope. The remaining areas are graded as per max lot grading. Note - if the side, rear and front max grades are left blank it will just inherit the lots max grade.
Break lines are added for the protective slope and building pad.
Reviewing Parcel Max Grades
Within Civil 3D, after a Level AI run you can view the parcel areas and the SINGLE FAMILY parcel max grading.
Hover over the area to see the classification and the max grade for the area.
