Parametric Design Strategies for Collaborative Urban Design

Taking its point of departure in a student workshop on parametric urban design, this paper explores some potentials of a parametric design approach for collaborative urban design. In the workshop, the CityEngine software was used as the design tool, and the object of the design was a contested urban space, subject to urban renewal. A key aspect of the workshop therefore, was to develop different design scenarios and to use parametric design software to communicate the scenarios spatially, as well as to mediate between them.

Parametric urban design is a potentially powerful tool for collaborative urban design processes. Rather than making one-off designs which need to be redesigned from the ground up in case of changes, parametric design tools make it possible keep the design open while at the same time allowing for a level of detailing which is high enough to facilitate an understanding of the generic qualities of proposed designs.

Yet, in any collaborative urban design process, some aspects – or parameters – are more likely to be relevant to deliberate than others. And they are not likely to be the same for different design cases. In one case, density and building style may be topical, while in another case, environmental issues or the distribution of different building programs may be relevant issues to analyze and negotiate.

Urban design, due to the complex nature of urban space, as well as the multitude of vested interests in urban space, can be described as a complex system. As Schön has pointed out, different professionals can not sustain with their professionalized knowledge within a complex system. They need to exit the autonomous structure of their professions. This brings forth the difference between collaboration and cooperation. Achten points out that the nature of cooperation is working alone with distributed design problem packages which means decomposition of design problems into tasks and working on them individually. On the other hand, collaborative design is based on communication. Participants work together on design problems in an integrated design process.

In addition to the collaboration between professionals, participation by different non-professional stakeholders, such as residents, local authorities, non-governmental organizations and investors, is another important component of collaborative urban design processes. The involvement of community in decision making process started in 1960’s to increase social responsibility Participation seeks to enable the equality among stakeholders and to constitute the notion of belonging and being part of a community. However, participatory design can be time consuming and too divergent due to the involvement of non-professionals.

Democratic involvement of different stakeholders has been studied for decades. And in the wake of these studies, different participation formats have been developed. However, non-designer professionals and non-professional stakeholders alike typically lack the capacity to fully understand the spatial implications of planning and design decisions, unless they are presented with relatively detailed architectural models, whether physical or virtual. This however, typically presents steep demands in terms of time and resources.

As a foundation for our work with parametric urban design lies the hypothesis that a parametric approach to collaborative urban design holds great promise with respect to render the design process more effective and more informative. Parameterization of design principles, in other words, may overcome many of the problems of closed design systems and facilitate participation. By way of parametric design tools, stakeholder participation can be conducted with more detail and in less time consuming ways.

The workshop which forms the point of departure for this paper was held at Istanbul Technical University on December 14-17, 2012. In the course of the four-day workshop, senior computational design students were asked to develop different design strategies for an urban renewal area and subsequently to script design scenarios which reflected the strategies. By means of role playing, the students took on views of different stakeholders. Hence, three different approaches were adopted; a conservative approach for maximum conservation, a radical approach for maximum transformation, and a hybrid approach negotiating different spatial and land use interests in between these two extremes.

In the course of the workshop, the students had to continuously consider how to script their design ideas in CityEngine. As the mediation between different design scenarios were an important component in the workshop, they also had to consider which aspects of their design to parameterize, i.e. to be able to subsequently modify. While on the overall level, an important pedagogical aim of the workshop was to introduce the notion of collaborative design to the students and how to facilitate it by means of parametric design software, on the peer to peer level of the students – due to the relative ease of use of CityEngine – collaborative design spelled out in the sharing of snippets of code and exchange on how to solve different scripting challenges.

The paper is organized into an introduction, three main sections and closing section with conclusions and perspectives. The first section of the paper gives a theoretical discussion of the notion of collaborative design and the challenges of collaborative urban design processes. The second section introduces the potential of a parametric design approach to overcome these challenges for collaborative urban design, and how they can be addressed by the use of CityEngine. The third section presents the student workshop and the main findings and shortcomings of the workshop, as well as some a posteori reflections and refinements of the workshop results. The paper concludes with some perspectives for further research on parametric design as a tool for collaborative urban design processes.