Design to build

Keep your skills on the button

Design to fabrication is an industry-wide challenge. Developing smarter workflows allows us to claw back significant ground from design and construct contractors, and gives more time to finesse ideas through later construction stages.

Recently I spoke at the MelBim conference on a workflow we developed for the design, analysis and documentation of native Revit geometry for a cold bent glazed facade. In cold bending, a glass panel is deformed through one corner to achieve a double curved surface. It is done on site: a threaded rod is slowly tightened to a precise predetermined distance based on the panel’s shortest length. As a facade system it is a little more expensive than flat panels and a lot cheaper than hot formed curved glass.

Our workflow for this project was partly shaped by recent developments on the parametric documentation front – the new release of Revit’s node-based scripting plugin Dynamo. This software speeds up modelling and documentation by providing a flexible node based coding pipeline like Grasshopper. The code we create can help a user to work faster/smarter, or completely automate the input of geometry. This method of working keeps project tasks open to a wide cross section of the office.

Dynamo 0.8 has a completely new interface that closely resembles the familiar Grasshopper and Revit buttons. The user buttons reside left of screen and are grouped into categories such as analyse, geometry and operators. The main workspace allows you to toggle between a node editor and a geometry preview window, allowing the user to check the code before executing it. Autodesk seems to have worked through some of the Dynamo bugs that caused spontaneous crashing and failure to refresh live data streams. The program is not perfect but the Dynamo release is now stable and reliable, suitable for mainstream architectural workflows.

The cold bent facade was designed in Rhino and Grasshopper; we extracted unique characteristics from each glass panel as lines of data linked to a csv file.

The data in this csv file was used to populate parameter fields in a smart adaptive family inside Revit. For this workflow, Dynamo was used to read the csv file data, reorganise the information into packets of family parameters and populate the Revit model using the csv data to drive key family type dimensions (ie width, height, curvature, position in space). The newly placed geometry automatically updated as the design was tweaked in Rhino. There were no re-documentation or translation errors and components were scheduled, tagged, and represented accurately in plan and section. We then produced cutting schedules from the Revit panels that formed the basis for fabrication shop drawings.

We are moving away from geometry-heavy models in Rhino and Grasshopper as complexity is built into Revit native families and adaptive components. Architects must work alongside fabricators to keep pushing the boundaries of architecture – how better than supplying the shop drawings and machine code they need?

Alan McLean is an architect at Bates Smart Architects in Melbourne