The UN17 Village is an efficient design of timber façade cassettes for a pioneering residential project with green ambitions. The combination made it possible to quickly extract data from different sources and automatically generate workshop drawings of timber façade cassettes on a large scale.
The vision behind the UN17 Village is to address the UN's Sustainable Development Goals in a 35,000 m2 housing project on the tip of Ørestad in the capital region of Denmark.
To explore the potential of different sustainable solutions, one of the residential blocks, Building E, is designed as a 7-story wooden structure that will become the tallest timber construction in Denmark. While we also used Tekla to design this specific building structure, this submission will focus on our efficient design of timber façade cassettes for buildings E, A, C, and D.
We created an automated workflow that combines Tekla with parametric design and extracts data from different sources to quickly model the cassettes and produce large quantities of workshop drawings ready for production.
Developing a more sustainable concept
The first step was to develop a general structural concept for the cassettes, which was achieved through an iterative process between MOE and the contractor CG Jensen. To significantly reduce the amount of waste, the concept was designed to consist of timber elements that closely matched the lengths of timber available from the supplier.
Furthermore, the design team found a way to avoid using laminated timber, which resulted in a considerable CO2 reduction and a cost reduction of 2 mDKK for one building.
With the help of Tekla Structures, the concept was easily made adaptable and optimized, while Tekla served as the visual tool and platform for collaboration to ensure proof of concept. When the general design concept was in place, a small number of Tekla components were developed based on the design to enable the parametric modeling and controlling of all the cassettes in Grasshopper via the Grasshopper-Tekla Live Link.
Combining data
Despite the general design concept, the line of cassettes contains many variations and different attributes to comply with the diverse building designs. Each cassette is produced as a fully functional unit, complete with weatherboarding on one side, plywood on the other, and mounted with doors/windows, including fittings and sills. The cassettes are also wrapped for moisture protection for outdoor storage until mounting and fitted with a lifting system for CLT. Building E was designed as the project's first residential block, and it alone contains 331 cassettes representing a large amount of varying data.
Conventional modeling and the manual typing of all the different inputs would have been a time-consuming task. The incoherence between different building models and data is a well-known challenge in many building projects where automation would be valuable, and this project proved to be no exception. The structural design is produced in Tekla Structures, whereas the architects use Revit for their design which contains information regarding the location and properties of windows and doors. In addition, the window manufacturer provides data for the windows while the contractor provides information about the production flow and mounting schedule.
The solution was to use Rhino-Grasshopper for the parametric design, which made it possible to generate a multitude of cassettes with the homemade Tekla components. An important precondition for this solution to work was the ability to extract and combine data from both Revit, Excel, and Tekla.
To begin with, we defined the attributes needed for each cassette and developed a data structure for how to compile data from different sources. The link in the data structure and the relation between all models were made by comparing the three-dimensional locations of all the elements.
Thanks to Grasshopper-Tekla Live Link and Revit plugins, the data was easily integrated into Rhino Grasshopper. Data from the window manufacturers and architects' Revit models were extracted directly. Some attributes such as materials, id-numbers, dimensions, etc., were transferred directly to the structural model in Tekla using the developed data structure. Some data was temporarily transferred into a spreadsheet for final review and editing, depending on the quality of the source model.
Following this exercise, Rhino-Grasshopper automatically feeds data to the Tekla component, which serves as a template for the design of cassettes. For this to work, MOE designed the template to match the applied data structure and information needed for every cassette.
The Tekla component is distributed as multiple instances of the different cassettes into the Tekla building model, generating production-ready drawings for the manufacturer. The production of drawings is made possible due to the very detailed cassette models, which have a LOD of 450. The Tekla Model also formed drawings for visualizing the installation plan.
With this workflow, we eliminated the repetitive and conventional modeling with help from computational design and new ways of using the interoperability between different programs.
The use of parametric designs enabled us to incorporate the changes from the architect automatically as the project proceeded and the final design came into being. When we defined the rules and method for the first cassettes for Building E, we laid the groundwork for designing the following buildings.
The future potential
The combination of Tekla Structures, parametric design, and openBIM has proved worthwhile in this project. The trinity is already famous for solving challenges concerning advanced structures. However, this project demonstrates the positive impact the automation process can have on common building projects also in terms of efficiency. Especially because the final product is production-ready drawings.
In the ongoing mass production of commercial and residential projects with less challenging geometry, the building industry tends to stick to the traditional procedures and continue with business as usual, wherever innovation does not seem essential for getting the job done. However, our results show great potential for automated workflows in Tekla Structures and computational BIM, even if it requires a little more preparational work in terms of time, innovation, and technical efforts.
