A computational design approach for enhancing precinct walkability: informing design processes via agent-based modelling

Abstract

This thesis aims to investigate how to inform concept design iterations by integrating walkability evaluation with pedestrian agent-based modelling (ABM) via developing and implementing accessible CAD tools.

While we have entered the post-digital era by the end of the last century, computer-aided design (CAD) has become a crucial and globally ubiquitous component of design practice. Many functions and new ways of working, including BIM and virtual simulation, would not have been conceived as possible in the architectural industry before the advent of digital practice, yet they are now regarded as indispensable within the profession.

Meanwhile, the emergent design topic of walkability has been increasingly recognised as a pivotal component of urban liveability and sustainability over the past twenty years. As a result, facilitating pedestrian-friendly environments is now becoming an urgent need for many urban design and planning projects, and computer-aided design has played a significant role in prompting this agenda.

As there is no universally agreed upon measurement of walkability, and both objective and subjective evaluation methods coexist in the current urban design scheme, this thesis suggests that using ABM can be advantageous and beneficial for both methods through different implementation. Therefore, the interest of this research is to develop a computational design strategy for different speculations by applying flexible and user-friendly ABM applications.

This argument has been tested and discussed with the following four tasks: The first includes an in-depth study of computational design strategy, complexity issues and emergence phenomena involved in urban design. The second is to understand different walkability evaluation criteria and how agent-based modelling can be useful under different circumstances. Then, the third task examines existing ABM technologies by identifying their potential adaptations and proposes new digital prototypes that are succinctly focused on precinct walkability issues. Last, the prototypes will be further optimised and validated in two case studies in Arden-Macaulay, Melbourne, Australia and Ecocity, Tianjin, China, with multiple degrees of design speculations.

The two ABM prototypes I developed have been shown to be feasible for pedestrian simulation at the precinct level and are accessible with considerably less cost than other commercial platforms. The Modular Scripting prototype offers a new interactive simulation approach for integrating walkability considerations in the urban design process with a ‘reactive scripting’ function that enables designers to calibrate during the loop. The Game Engine prototype, on the other hand, recognises that the schematic design loop is not merely an engineering endeavour and suggests a synthesis simulation method, which makes subjective evaluation possible; here, an architect or urban designer can gain a more intimate sense of their occupant's experience through ABM and let that enrich their design decisions.

The main contributions of this research can be summarised in four ways: 1) It examined existing ABM methods and toolboxes and investigate how ABM could integrate with walkability evaluation ; 2) It developed two accessible and flexible ABM prototypes for graduate architects and small design firms; 3) It discovered how to properly set up pedestrian simulation in walkability-prioritised and precinct scale projects; and 4) It investigated how to use ABM tools to inform design decisions in different conceptual proposals and how this could accommodate ever-changing design iterations.

This thesis concludes that the proposed computer-aided design approach can demonstrably synergise both pedestrian ABM and walkability indexing into the schematic design process. The inherently flexible design approaches and accessible ABM tools can be adopted by different design practitioners and academics, as well as potentially other disciplines. The integration between advanced digital techniques and speculative design thinking can expand the realm of the design communities and offer them new possibilities to embrace a design agenda for healthier and more sustainable cities.