José Nuno Beirão

Towards a methodology for flexible urban design: designing with urban patterns and shape grammars

Traditional urban plans use definitive design systems, without the flexibility required to deal with the complexity and change that characterize contemporary urban societies. To conceive urban plans with increased flexibility, a shape grammar-based design methodology is proposed which is capable of producing various design solutions instead of a single rigid layout. In this approach the plan is a design system encoding a set of alternative solutions, rather than a single, specific solution. This methodology was developed on the basis of the analysis of existing plans and on a series of experiments undertaken within the controlled environment of design studios. Results show that shape grammars produce urban plans with nondefinitive formal solutions, while keeping a consistent design language. They also provide plans with explicit and implicit flexibility, thereby giving future designers a wider degree of freedom. As a result, they are particularly appropriate for dealing with complexity and change throughout the legal lifespan of the plan. Finally, they provide students with a concrete methodology for approaching urban design, fostering the development of additional design skills.

City Induction: A Model for Formulating, Generating, and Evaluating Urban Designs

Urban planning and design have a considerable impact on the economic performance of cities and on the quality of life of the population. Efficiency at this level is hampered by the lack of integrated instruments for formulating, generating, and evaluating urban plans. This chapter describes the theoretical foundations of a research project, called City Induction, aimed at the creation of a model for the development of such an instrument, departing from existing theories, which are integrated through a discursive grammar. The proposed model is composed of three sub-models: (1) a model for formulating urban programs from the analysis and interpretation of the context, based on Alexanders pattern language; (2) a model for generating urban plans that match the program, based on Stinys shape and description grammars; and (3) a model for evaluating urban plans, that can be used for analyzing, comparing and ranking alternative solutions, departing from Hilliers space syntax. A common urban space ontology guarantees the syntactic and semantic interoperability among the three sub-models. This ontology will be used to structure and codify information into a Geographic Information System (GIS), which will be the kernel for the computer implementation of the larger model. A CAD system is used to construct 3D models from contextual information stored in the GIS. In short, following Stiny and Marchs design machines concept, the goal is to create an urban design machine that is able to produce flexible urban plans at the site planning level.

Analysis and Classification of Public Spaces Using Convex and Solid-Void Models

Urban planning and design are increasingly often supported by analytical models of urban space. We present a method of representation for analysis and classification of open urban spaces based on physical measures including three-dimensional data to overcome some observed limitations of two-dimensional methods. Beginning with “convex voids” constructed from 2D plan information and 3D data including topography and building facade heights, we proceed to “solid voids” constructed by aggregation of convex voids. We describe rules for construction of both convex voids and solid voids, including basic forms and their adjustment for perception. For analysis we develop descriptive characteristic values such as enclosure, openness, granularity and connectivity, derived from more basic geometric properties of the void representations. We also show how combinations of these values can be correlated with urban open space typologies, including commonly accepted traditional ones as well as previously unnamed classes of space. Concluding with discussion of some future planned developments in this work, we also propose that such methods can contribute to better understanding of the relations between urban forms and their perception and use, so as to guide urban transformations for improved urban quality.

Automated generation of versatile data model for analyzing urban architectural void

Abstract Urban environments are defined and modeled in a variety of ways depending on the scientific approach to analyze them. Even though a number of analysis could benefit from using a single model and re-using results of one for the sake of the other, so far no single data model is available. Moreover, the existing standardized models focus on describing objects in and around urban architectural void rather than the spaces themselves. Nevertheless, a number of phenomena such as heat, energy, pollution, also including social and mobility aspects would undoubtedly benefit from using a model that is explicitly focused on defining the urban architectural void and its characteristics as continuous field, interconnected network or series of spatial units. Therefore, this paper aims to suggest a versatile data model that would allow to separate, interpret, analyze and visualize the urban architectural void using a standardized automated procedure. The model relies on Gestalt theories for space compartmentalization. It allows performing various kinds of analysis and storing their results in a unified format using core concepts of GIS. The model can be rendered both as a 2D and 3D representation. Finally, user intervention and parameter calibration is allowed at every principal step of an automated procedure.

Meta-PREVI Grammar

This paper describes part of a wider research that aimed at using Shape Grammar to generate more diverse and interesting urban spaces in Brazilian Social Housing developments. A shape grammar corresponding to design patterns was inferred from the PREVI Lima urban plan developed by C. Alexander [1] in the 1970s. The grammar was inferred from the plan layout and from the text instructions (or pattern descriptions) presented by Alexander, and can be applied to design new plans within a wider formal universe than what the plan layout would suggest. The final section of the paper points towards the development of generic grammars as a way of encapsulating good qualities of certain design projects and applying them to new situations.

Sortal Grammars for Urban Design: A Sortal Approach to Urban Data Modeling and Generation

Grammar formalisms for design come in a large variety, requiring different representations of the objects being generated, and different interpretative mechanisms for this generation. At the same time, all grammars share certain definitions and characteristics. Building on these commonalities, we consider a component-based approach for building grammar systems, utilizing a uniform characterization of grammars. Sortal representations constitute the components for this approach. They implement a model for representations, termed sorts, that defines formal operations on sorts and recognizes formal relationships between sorts. Each sort defines an algebra over its elements; formal compositions of sorts derive their algebraic properties from their component sorts. This algebraic framework makes sortal representations particularly suited for defining grammar formalisms considering a variety of algebra, and match relations (or interpretative mechanisms). For urban design and simulation, sortal grammars may include, among others, descriptive grammars, shape grammars, GIS-based grammars and any combination thereof.