A note on Parametric design

Architectural design has gone from hand drawing to 2D CAD to explicit 3D modeling, and of course, to BIM. Generated digital content is all around us. Designers are starting to realize the potential power of generated forms as opposed to explicitly modeled forms. As demonstrated by the complex forms of many new projects in the Middle East and Asia in particular.

I intend to post a few articles on a combination of Parametric Design/ BIM. Followed by articles about Performative Design where I will describe in detail the nuances and advantages of each.

Why am I writing about Parametric Design? Processes like Parametric Design affect the earliest stages of a design effort. And have salting impact on the eventual design and operation of a building. It is a paradigm shift compared to more traditional, normative design processes. It is important that we, as a profession, explore and understand PD and BIM to get a complete picture of the digital design ecosystem.

If you are still reading this entry you will need to know some definitions.

Parametric Design

There isn’t a single definition that captures the essence of Parametric Design. This quote captures the essence of Parametric Design “Generative design is not about designing a building, It’s about designing the system that designs a building” from Lars Hesselgren. He is one of the founding members of the Smart Geometry Group, a nonprofit organization of AEC professionals interested in using computational and parametric approaches to design that encourages collaboration between practice, academia, and research.

Performative Design

According Dr. Andrew Marsh, creator of the widely used Building Performance Analysis application Ecotect, Performative Design considers the wide array of building performance issues with all other aspects that shape a design from the earliest, most formative conceptual stages. It does not, as the name might suggest, focus only on meeting performance criteria through the manipulation of form. Instead, it requires synthesizing performance and form when the design concept is still sufficiently plastic and pliable so it can be shaped by these considerations as much as possible. Performative Design processes are viable because the tools for simulating and analyzing buildings are becoming faster, flexible, and simpler to use. This means that designers can use these programs themselves, instead of relying on specialists, to apply even the simplest block models. This, in turn, allows them to effectively integrate their results into the early designs and pursue a whole range of design ideas, rigorously test and accept or reject them very early in a project.

In other words, think of using certain tools to analyze the heat gain on the façade of a building. That is an example of performative design.

Features

(image & design credit: SOM, Chatrapathi International Airport, terminal 2)

Parametric Design is significantly different because you do not begin by creating a form; you start by defining the rules that shape a form or even by defining an individual component of the eventual form. The process might be something like:

• Define component

• Capture relationships

• Define constraints

• Generate form

• Iterate by varying any of the first three inputs

The defining component can be a simple geometry, but the resulting form can be many times more powerful and complex. For example the complex structures found in ant hills and bee hives result from simple repeating components. By harnessing the computational prowess of generative algorithms we can design and rationalize forms that human minds typically cannot conjure; Gaudi and Nervi as examples of exceptions. Despite the complexity of the resulting forms, design iteration is quick and the feedback is instantaneous. This allows designers to test many “what-if “scenarios rapidly. It removes the time limitation of explicit modeling and accelerates interaction with resulting form.

Examples

There are many examples of buildings using a Parametric rationale but a specific project that I would like to mention is the SOM designed, Chatrapathi International Airport, terminal 2, in Mumbai, India. This project demonstrates in a visually obvious manner the integration of the parametric recursion of a repeatable element that is then used to populate a surface and eventually create a compelling architectural statement. 

At Studio Parametric, we have harnessed the power of Parametric Design & BIM one of our Middle East projects for a New York based design firm.

(image & design credit: FXCOLLABORATIVE, New York)

In this case, the façade was a saw-tooth module arrayed along multiple curves while stepping in and out at different floors. By using generative design ideas, we were able to study slightly different versions of the façade in a short amount of time. I will explain this process in detail in a subsequent post. The saw-tooth module was the individual component and had a certain relationship to the curves along the façade; the number of panels and their justification and height along each curve was constrained. This resulted in a form that was iterated by varying the (a) module, (b) relationship to the curve, and (c) constraints along the curve. 

Tools

The software that was used in this process was Mc Neel’s Grasshopper (a Rhino plug-in),

Generative Components by Bentley (a Micro station plug-in) & Revit’s Conceptual Massing environment. Apart from these tools, scripting routines such as VB, C#, and Python can be used independently or in conjunction with the above software. 

I would like to end this post with a quote from Henry Ford “If I’d asked my customers what they wanted, they’d have said a faster horse.”

CAD = faster horse!