Parametric design is a design method in which features, such as building elements and engineering components, are shaped based on algorithmic processes rather than direct manipulation. In this approach, parameters and rules establish the relationship between design intent and design response. The term parametric refers to the input parameters that are fed into the algorithms. While the term now typically refers to the use of computer algorithms in design, early precedents can be found in the work of architects such as Antoni Gaudí. Gaudí used a mechanical model for architectural design (see analogical model) by attaching weights to a system of strings to determine shapes for building features like arches. Parametric modeling can be classified into two main categories:
Propagation-based systems, where algorithms generate final shapes that are not predetermined based on initial parametric inputs. Constraint systems, in which final constraints are set, and algorithms are used to define fundamental aspects (such as structures or material usage) that satisfy these constraints. Form-finding processes are often implemented through propagation-based systems. These processes optimize certain design objectives against a set of design constraints, allowing the final form of the designed object to be "found" based on these constraints. Parametric tools enable reflection of both the associative logic and the geometry of the form generated by the parametric software. The design interface provides a visual screen to support visualization of the algorithmic structure of the parametric schema to support parametric modification. The principle of parametric design can be defined as mathematical design, where the relationship between the design elements is shown as parameters which could be reformulated to generate complex geometries. These geometries are based on the elements’ parameters; by changing these parameters, new shapes are created simultaneously. In parametric design software, designers and engineers are free to add and adjust the parameters that affect the design results. For example, materials, dimensions, user requirements, and user body data. In the parametric design process, the designer can reveal the versions of the project and the final product, without going back to the beginning, by establishing the parameters and establishing the relationship between the variables after creating the first model. In the parametric design process, any change of parameters like editing or developing will be automatically and immediately updated in the model, which is like a “short cut” to the final model.
Parameter The word parameter derives from the Greek for para (besides, before or instead of) + metron (measure). If we look at the Greek origin of the word, it becomes clear that the word means a term that stands in for or determines another measure. In parametric CAD software, the term parameter usually signifies a variable term in equations that determine other values. A parameter, as opposed to a constant, is characterized by having a range of possible values. One of the most seductive powers of a parametric system is the ability to explore many design variations by modifying the value of a few controlling parameters
History (early examples)
Analogue parametric design
One of the earliest instances of parametric design was the upside-down model of churches by Antoni Gaudi. In his design for the Church of Colònia Güell, he created a model of strings weighted down with birdshot to create complex vaulted ceilings and arches. By adjusting the position of the weights or the length of the strings, he could alter the shape of each arch and observe the impact on the connected arches. He placed a mirror at the bottom of the model to see how it would appear when built right-side-up.
Features of Gaudí's method Gaudí's analog method incorporated the main features of a computational parametric model (input parameters, equation, output): The string length, birdshot weight, and anchor point location function as independent input parameters. The vertex locations of the points on the strings serve as the model's outcomes. The outcomes are derived using explicit functions, in this case, gravity or Newton's laws of motion. By modifying individual parameters of these models, Gaudí could generate different versions of his model while ensuring the resulting structure would stand in pure compression. Instead of manually calculating the results of parametric equations, he could automatically derive the shapes of the catenary curves through the force of gravity acting on the strings.
German architect Frei Otto also experimented with non-digital parametric processes, using soap bubbles to find optimal shapes of tensegrity structures such as in the Munich Olympic Stadium, designed for the 1972 Summer Olympics in Munich.
Architecture
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