Thanks for doing this! I have been starting to work on this at a very basic level to wrap my head around computational design.
I’ve seen some of the models that architects use for space planning or Infraworks uses for path optimization. I figure that if this can be done horizontally, it can be done vertically for site grading as well.
Description:
Site grading can be complex for multi-family sites. Think 19 buildings inside of a hectare. Site grading has several relationships and constraints throughout a project: maximum/minimum slopes for walks, maximum/minimum slopes for driveways, number of low points (catch basin locations), maximum depth of low points, underground service elevations (min cover) from both ground and unit basements/slabs/footings, existing boundary elevations and cut/fill quantities.
Inputs:
• Boundary elevations: the elevations of the perimeter of our site: Can dictate adjacent building upper and lower limits
• Service horizontal location and elevation: The locations for the 3 deep services: sanitary, storm and water. I guess this could almost be its own generative design challenge. This input set to minimum requirements typically sets the lower limit for road and building elevations.
• Road profile and location: Road location is normally set by the architect, cross section by a municipal standard.
• Road critical point locations: critical points along the road. E.G. intersections, corners, or fixed points in the design.
• Maximum ponding depth: the elevation difference between the local low point and the lowest adjacent high point. Typically found along a centerline swale or road profile. Is set by a municipal standard. And this example ignores vertical curves.
• Building, road and walk footprints: The different terrain purposes have different variable requirements.
Variables:
• Road critical point elevations: Vertical elevations for critical points along the road. E.G. intersections, corners, or fixed points in the design. Lower limit is set by deep utilities, upper limit is set by maximum grades and number of low points.
• Building main floor elevation: In this case, used to quantify earthworks and set adjacent grades to the road and boundary. Lower limit is set by the highest of:
o Utility invert
o Adjacent road elevation
o Adjacent boundary elevation
• Upper limit set by the lowest of:
o Adjacent road elevation
o Adjacent boundary elevation
• Number of low spots per centerline swale/road. This is occasionally forced to induce surface storage of water.
Generate: I’m still brainstorming how this would work. Its really a relationship between the road, the adjacent buildings, boundary, and tie in services.
The model itself would be a surface that is made from the boundary, road profile, any walk/driveway features, and the building. The surface would use slope shading for review in addition to the evaluation criteria. The lines that create the surface can then be imported into the cad model as feature lines, and detail design can progress from there.
Evaluate:
Number of low spots: dictates cost in catch basin construction and surface ponding locations. [-]
Cut/Fill quantities. [-]
Site Slopes: Viewed through slope shading
Average site slopes for:
• Driveway [-]
• Road [-]
• Walks [-]
• Landscape [-]
Average building height at main floor [-]
Site Storage: how much water is stored on the surface of the site before being collected by the storm system in major events. [+]
Overall, grading would be the end goal. It seems the most complex at the moment. I also want to try generative design for storm water management facility ponds, sanitary lagoons, and optimizing utility main alignments. Let me know if you would like me to flesh out the other ideas.