The data and information content of BIM plays a key role in the design process, whether it is for quantity surveying, budgeting, operations, or even simulation. The spread of this approach and software solutions provide increasing opportunities for free BIM applications. One relatively new but rapidly expanding sub-area is parametric design.
Parametric design is characterised by the fact that it is based on mathematical relationships that can be clearly described. The software produces the desired element, geometry, etc., according to a set of rules or algorithms. Typically, it is used to design mass form, simple simulations, or the design of parts of a building. It is also increasingly used to create simulations such as lighting, building energetics, or even structural design with a fast calculation of approximate dimensions. Thus, the design object is not produced using a traditional working method, so traditional processes are not generally applicable.
When it comes to parametric design, one usually thinks of complex, organic, dynamic shapes. But it’s not just in the construction industry, it also plays a key role in sculpture, interior design, fine art, and the increasingly popular 3D printing. However, beyond the spectacular mass shaping, there are countless advantages to this design method. Not only in building construction but also in civil engineering, infrastructure and even bridge design, there are many opportunities.
Let’s look at some specific examples:
Zaha Hadid, who passed away a few years ago, and her design partner Patrik Schumacher are perhaps the best-known exponents of parametric architecture. This kind of approach has long been used in civil engineering to shape buildings. Perhaps her most iconic building is the: Heydar Aliyev Center \ Baku, Azerbaijan \ 2013:
Design, art, jewelry design are all areas where free-forming is strongly emphasised. Parametric design also makes it possible to design configurations that would be more challenging to draw. Biomorphic (naturally occurring) shapes are often used or abstracted in some way. With parametric design, an algorithm can be created that can, for example, fit the spiral line of a snail shell to different shapes, or easily fit the veins of a tree leaf to a shape of a sole:
For the technological design of ancillary construction structures, if it is done in 3D, a 3D model of the structure (or part of it) is also needed as a reference for the substructures. This is why speeding up workflows, improving precision and automation are increasingly important. This is exactly what parametric design and BIM offer, and several developments have already been made in-house using these methods. One such solution is an internally programmed GDL (Geometric Description Language) tool. In ArchiCAD software, it is possible to create custom objects or to parameterise them. This development provides a solution for precast reinforced concrete beam overpasses and underpasses on roads, as they are very similar in most cases. In the setup panel, the types and dimensions of the different components can be defined, and the 3D bridge structure is automatically drawn.
The main advantage of parametric design is that the user of the algorithm does not need to manually create each model detail, but only needs to set the main parameters in a predefined system and the model changes automatically based on them. Even in the event of a potential modification, there are great advantages to this approach. E.g. in the same section, you can find circular, square or even ‘Y’ shaped pillars, and if you change the pillar shape you can quickly change the pillar shape by selecting the right type in the setting panel. After that, all connecting structures will be adapted to the new design.
The added value of BIM to support the industry’s increasingly complex business practices is indisputable. The potential of parametric modeling further demonstrates the strength of the BIM method: modeling times have been significantly reduced and accuracy is increasing. In addition, the main strength of the method is that it can support many bridge projects. In fact, owing to the large number of parameters defined, it is possible to generate very diverse geometries. In contrast to direct modeling, such a parametric tool can be used to quickly create multiple models at the start of the design process, allowing more accurate alternatives to be explored, and can therefore be used as a decision support tool.
Author: Dóra Szalai – BIM manager