We are seeking proposals to develop a Grasshopper-based digital tool that identifies and places surface drain points on virtually flat paved areas. The tool must output Rhino3D geometry for integration and documentation in Revit.
Design Brief
The tool will support drainage design on flat hardscaped areas such as podiums by:
Analysing the existing finished surface levels
Introducing optimised low points (drain points)
Modifying the surface geometry to create compliant cross-falls (1%–2.5%)
Dividing the surface into watershed zones, each draining to a single point
Minimising the number of drain points required
Inputs
- Pavement Boundary: A closed polyline or surface edge (Rhino3D).
- Finished Surface Levels: A mesh or gridded surface representing current grades.
- Slope Constraints: Minimum and maximum slope range (typically 1%–2.5%).
Outputs
1. Rhino3D Geometry (for use via Rhino.Inside Revit)
Drain Point Locations and Levels: 3D points with X, Y, Z values
Modified Surface: Adjusted grading to direct runoff to each drain point
Watershed Areas: Closed polylines defining the drainage zone of each point, with areas in square metres
2. Revit Documentation Outputs (for reference only – not part of this task)
These outputs will be produced in-house using the Rhino3D geometry:
Pavement boundaries
Drain point symbols and FSL labels
Spot levels at grade changes
Contours (100–200mm interval, as appropriate)
Slope arrows with % values
Watershed boundaries
Full sheet layout with legend, scale, and north arrow
Deliverables
1. Functional Tool
A working Grasshopper definition (.gh file) that:
Accepts the specified inputs
Identifies optimal drain point locations
Modifies the surface to meet slope constraints
Outputs the geometry listed above
The tool should be:
Clearly structured and labelled
Usable by team members with basic Grasshopper knowledge
Built using standard components (note any required plugins)
2. Documentation Package
A short user guide explaining how to use the tool and required inputs
(Optional) A video walkthrough (max 3 minutes)
3. Revit-Ready Geometry
Geometry structured for clean transfer to Revit via Rhino.Inside
Sufficient for production of drainage documentation as described
Submission Requirements
Please submit:
Your quotation and estimated delivery time
A brief overview of your proposed approach
Examples of relevant past work or experience
Send proposals to:
Subject:
- Surface Drain Locator Tool: Quotation
