Before addressing how architecture and engineering firms can harness parametric design a short description of how BIM intersects the topic is appropriate. In this article I draw very little distinction between building information modelling, computational architecture and parametric design. Sometimes the differences between these topics is very important, today approaching the topic from a building design management angle each relates to the other so tightly in the design process such distinctions become unhelpful. I'll confess to being a bit of a math nerd and one of my favourite applications of calculus is the parameterization of systems. Formally the topic is applied to modelling dynamic systems but it's a good analogy for how we need to break down and organize a building model to start leveraging the advantages of digital design. If a building has three different roof heights, each can be assigned a variable. If a building has two window sizes, each can be assigned a variable and so on. The same way applied mathematics breaks down a complex dynamic movement (i.e. free-body diagrams), a building model too can be thought of as system of equations. Parameters are the handles we use in order to control the equation and model. The reason there is so much overlap in the topic is because pretty much any information attached to the digital model geometry can be considered a parameter, though this time not so much in the mathematical sense but instead a very functional one: Material type, material specifications, manufacturing information etc., in addition to every type of relation and offset amongst the geometry that is conceivable by the human mind or computer. These parameters allows for different types of model control and comparative analytics.
Breaking down four ways firms can start leveraging parametric design today, parametric design:
- Can streamline the production of a construction drawings.
- Supports the search for an optimal design solution through rapid design iterations.
- Helps develop a building's advanced sustainability features and functional requirements through comparative analytics.
- Can generate complex yet elegant design forms.
Construction Drawings. Even the most basic applications of parametric modelling require skill and foresight to ensure success. Experience correlates only weakly with its application because the process is so complex and other factors begin to overwhelm the process. Architects, engineers and industry professionals need to have an excellent understanding in how the model will behave when the programmed variables change. For example the basic variables discussed above: Roof heights, floor elevations, offsets, etc. When design changes come across my desk sometimes I smile ecstatically – almost laughing out loud – because of how trivial it can be to make complex comprehensive changes (assuming the digital model has been caringly and intelligently built). All my beautiful details updating automatically across the drawing set. An example of this from last year was when an engineer brought some foundation changes to my desk. He looked so despondent because he thought I would have to spend half a day updating everything. Instead, with a few clicks, I updated everything while he was standing there, and could show him the updated sections and annotations. The ability of a well-designed building model to quickly absorb changes makes me smile even now as I write this remembrance.
Design iterations. Sometimes the solution space for a proposed design is truly prodigious; and while I love discussing the intersection of complexity theory and architectural theory, here we need to remember our priority should be searching the vast solution space of possible designs efficiently and productively. Here the task is supported by being able to generate and test many possible proposed designs efficiently. Clients have a lot on their plates and it's appropriate they ask for quantifiable ways to produce their expensive buildings. Being able to show the solution space was much more thoroughly searched leading to an even better high-performance building is an important way of distinguishing the project in the marketplace and ultimately offering the client a more valuable design.
Comparative Analytics. Having oodles and oodles of possible design solutions and making sure the solution space is well searched is only one step in creating a valuable building for the client. Comparing proposed designs relies on analyzing the differences between models. Comparative analytics is a field within computational architecture and all those parameters associated with the geometry are now needed to accurately model and control all sorts of conclusions about the proposed structure. These include energy modelling, solar modelling, building safety, material optimization, etc. A further step often seen in high-performance buildings is that results from predictive modelling can be fed back into the building model to optimize all sorts of things. The simplest example might be orienting a building to optimize the location's solar properties, but pretty much anything can be compared; material economization, mechanical systems, user travel paths, solar shades, and on and on. This is why beyond the formal skills needed to compare features, the subjective meaningful qualities of architecture again rise up to distinguish good architecture from great in what features were highlighted by the architect and client.
Parametric Forms. As referenced above, the advantages of parametric design can be utilized without any drastic changes in visual characteristics. It's still a strip mall but at least it's a computationally optimized one. Over the last number of years, however, several projects have been completed which, to my eye, establish parametric design as a visual style. (Calatrava's New York Oculus Station is very successful in this regard but Pinterest is as good a catalog as any to understand it further.) The notable feature of the of parametric exteriors and interiors is their seductive rhythmic variation. Looking forward, I hope parametric design isn't used for the sake of parametric design. As programming skills mature and expand amongst BIM professionals, there's going to be a tendency to use it everywhere. Complex patterns really are trivial to generate and critical thought will need to be applied to probe the meaning and depth of its use. It's the only way to ensure clients and communities get the beautiful sustainable architecture they deserve.