Westonbirt Walkway Generative CAD & Parametric Design
INTRO
MAKE applied specialist computational geometry and parametric CAD skills to support early concept development for the STIHL Treetop Walkway at Westonbirt Arboretum — one of the UK's most significant landscape and heritage sites.
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The project required a generative design approach capable of rapidly testing walkway routing options through the complex topography of Silk Wood, with all structural geometry updating automatically in response to route changes.
OS mapping and topographical survey data needed to be converted into accurate 3D terrain models to underpin all design decisions.
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MAKE converted detailed Ordnance Survey mapping and topographical survey data into data-rich 3D terrain models, providing an accurate geometric foundation from which all routing decisions were made — ensuring design choices reflected actual site conditions rather than simplified approximations.
A fully parametric walkway model was developed in Grasshopper, in which the entire structure — support columns, deck geometry, handrails, and transitions — was generated from a single input spline describing the walkway path in plan. Any modification to the route automatically propagated through the complete 3D model in real time, updating elevation and section drawings simultaneously.
Each support column was parametrically linked to the variable distance between the forest floor and the walkway deck at that location, automatically adjusting its geometry to suit the terrain. This approach compressed weeks of iterative redrawing into a process where route options could be evaluated in minutes.
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OS survey and topographic data converted to accurate 3D terrain model
Single-spline parametric model driving complete walkway geometry in Grasshopper
Auto-adjusting column geometry responding to terrain height variation at each location
Real-time update of elevation and section drawings on route change
CGI visualisation for stakeholder communication and planning support
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The parametric model delivered a step-change in design iteration speed for the project team, enabling meaningful architectural and engineering decisions to be evaluated rapidly against accurate site conditions.
The project demonstrates how advanced computational design tools — typically associated with product and industrial design — can deliver significant efficiency and accuracy benefits in landscape architecture and civil engineering contexts.
Read more about the thinking behind this project on our Insights page
A structure that could be rerouted and re-evaluated in minutes rather than weeks. Proof that the right parametric relationship, built once, can do more for a project's outcome than any amount of manual redrawing.
