384 SIGRADI 2010 / Disrupción, modelación y construcción: Diálogos cambiantes Generative House: Exploration of Digital Fabrication and Generative System for Low-cost Housing in Southern Brazil

ABSTRACT Generative House is a collaborative exploration of advanced technologies for lower-and working-class housing carried out by industrial and academic partners in southern Brazil. It seeks to test generative procedures and digital manufacturing to develop a flexible building system for low-cost sustainable housing in order to inspire future developments in this field by developing an urban grammar through manufacturing models and generative programming, as well as parametric design of panels assembled using digital fabrication. Scale models and full-scale prototype with timber boards have been built, demonstrating the feasibility of the approach proposed. However, further refinement of the adopted procedures and technical applications is required. KEYWORDS: low-cost housing, generative programming, parametric design, digital manufacturing, collaborative development. The population of the earth has increased ten times during the last two centuries, reaching eight billion of people, and it continues to grow (UN, 2005). Life expectancy has also doubled in the same period, from 40 to 75 years, which means that world demand for housing will dramatically increase in the years to come. Urbanization rates also increased from 30 to 80% in the same period; gross income and people's mobility grew in similar ranges, creating demand for better solutions that meet the needs of different climactic and socio-economic conditions. Despite all of these changes, design and construction have maintained traditional building procedures-construction is economic sector with the lowest productivity and industrialization rates (Haskwell, 2004). Fossil fuels now have a very short availability horizon due to dramatic increase in demand that is a response to the growing consumption of transportation fuel, construction materials, and heating and cooling systems for buildings. Global warning also compels us to make hard choices that require changing many processes, in particular the way in which we build and use of facilities, which are responsible for most of the world's energy consumption and carbon production. Types of architecture and their elaboration have to be changed radically over the coming decades in order to face these new environmental and social challenges. Technological evolution based on scientific knowledge and mass-production has advanced rapidly during the past two centuries, leading to alterations in the modes of production. However, architectural production is far removed from these procedures. Design is usually thought of as an isolated task, aesthetically focused on creating unique products; construction consists of linear handicraft sequences. This is particularly the case in developing countries where the demand for new buildings is very high. Governments of developing countries are promoting massive plans for low-income housing. This endeavor should be accompanied by novel approaches to production both in design and manufacturing. Customized mass production of housing was proposed in the seminal work of the SAR-group INTERVENCIONES URBANAS ENG / POR / ESP scale buildings, but failed to relate these to corresponding urban settings. Low-cost housing involves relatively low financial resources per unit when part of large-scale plans. This may imply identical units in which diversity is achieved through variations in urban configuration. Family makeup and changes made over time also determine variety and adaptations CasaG The Generative House (CasaG) constitutes an example of the utilization of advanced technologies in low-cost housing design, and was carried out by an international partnership between industries and academia in southern Brazil. Generative procedures and digital manufacturing were tested, and inspired the development of a sustainable building system for low-cost housing. The project structured urban and constructive grammars so as to stimulate flexibility and mass production of housing. In an exercise carried out in two workshops held at the SimmLab (Laboratory of Urban and Architectural Simulation) of the Universidade Federal do Rio Grande do Sul, PortoAlegre, Brazil in June-July and August-September, 2010, graduate and post-graduate students tested cutting-edge systems targeted to high-scope goals in order to encourage innovation in design, planning and construction. Initial Module The Generative House project initially researched environmentally-friendly industrial products for manufacturing building components. Composite-wood boards were chosen as the main material to be used in the construction because of their good physical properties, local provision, their originating from reforested woods, and their ease of manufacture. A regional industry supplied products and technical support. Panels were designed and tested with laser-cut 1:10 models. Full-size boards (1.84 x 2.75 meters) with maximum lengths close to the house's floor-to-ceiling height defined double walls, and an assembly system composed of perforations and joints was made out of the same material. Windows, doors, ceilings and floors were linked to the walls for structural support and assembly. In addition, a tridimensional module was established (2.60 x 1.70 x 2.60 meters) providing multiple alternatives of windows and doors. Additional coatings were considered because composite-wood boards do not have enough resistance to humidity and fire; proper thermal and acoustic insulation was provided. Studies of local weather and housing regulations were carried out parallel to the review of general requirements. Also several possible housing plans based on the initial module were studied to test the affordability of diverse room arrangements. Urban layouts A variety of housing alternatives to compose urban arrangements was tested through digitally manufactured models in order to select configurations with growth flexibility according to predefined living complexities. A great diversity of module groups were produced in white-plastic models 1:100. Several growth arrangements were studied following generative rules (shape grammar) and photographed step-by-step to allow further review of ventilation and orientation according to weather conditions and high density requirements. This procedure allowed researchers to define a basic configuration consisting of a row of 6-7 modules with a second adjacent row of 3-4 modules, a group called "embryo", with highest growth potential in few steps. This basic configuration allows for a basic 36 square meter house with two bedrooms, services and social space; consecutive enlargements of similar sizes reach 240-300 square meters in two stories. Testing different growth sequences, such housing types preserved good ventilation and functionality patterns, enabling out-door yards. The pattern generated adequate (proportionate) dimensions for local streets so as to encourage social interface in local public spaces. This system of arrangement was programmed in Rhinoceros-Grasshoper with a cellular automata plug-in in order to reproduce alternatives of growth and urban layouts. To define a rectangular grid according to the constructive modulation, attractor points were determined so as to encourage the initial house to be set in different lot positions on the block. An algorithm allowed random growth then refined through several recursions with the high percentage (80%) of coincidence with the tested models. This rate was used to accomplish a computer procedure to achieve the conditions and flexibility demonstrated by the models. Constructive System Development leads to the refinement and completion of the constructive system in order to enable a variety of layouts. This task involved the review of the design and properties of several components such as walls, windows, doors, roofs and floors. It establishes modular dimensions and varieties according to locations in the layout, but also offers the possibility to change and enlarge the configuration. The assembly system was developed to relate all components through a modulation and used a minimum number of joint pieces, including corners and connections to roof and floor, and also provided alternatives for windows and doors according to the modulation in order to maintain structural continuity. Complete 1:10 models of several units composed of two or three modules were made, with diverse possibilities of design and materials. The models were elaborated in 3 millimeter wide composite boards using a laser cutter. Some production difficulties were encountered due to the size of the model elements, such as laser beam adjustments due to board displacements causing minor errors affecting the overall assembly, as well as problems adjusting roof inclination with perpendicular cuts in order to afford supporting pieces and slots. Full-scale Prototype The last step of the project, currently in development and not to be completed until the Sigradi conference, is a full-scale prototype of the building system. Several changes of technical details due production conditions were carried on through CNC-machines for larger formats and products-in this case, with industrial boards cut into panels measuring 120 x 240 x 1.8 centimeters. This modified the procedure of cutting and assembly, as well as the roof system, corners and floor. The prototype will be assembled in a commercial showcase (ExpoAcabamento + Congreso Internacional de Arquitetura e Design, FIERGS, PortoAlegre October 20-24th), exhibiting diverse development models and urban arrangements. Conclusions This experience tested advanced technologies of design and manufacturing to develop a flexible building system for lowcost sustainable housing. It developed an urban grammar through manufacturing models and generative programming, as well as a parametric design of assembled panels using digital fabrication. Several material models and tests of constructive behavior were performed. It has inspired the construction of a full-scale prototype using industrial timber boards, on display in a public showcase. The collaborative work between faculties and students from different institutions and countries and different companies demonstrated the feasibility of the proposed approach. On the other hand, it revealed the need for the detailed refinement of such technical procedures, building attributes and applications. This work is meant to inspire future developments in the field, in order to target the exploration of new technologies to meet the world's urgent housing needs

Método da grade de atributos: avaliando a relação entre usuário e ambiente

Este artigo trata do desenvolvimento de método gráfico, apoiado em um modelo configuracional, capaz de representar, simultaneamente, atributos funcionais de conforto e comportamento de usuários em abrigos de ônibus. A partir da avaliação das condições de espera (posicionamento) dos usuários, pôde-se definir fatores físicos – denominados “atributos” – prioritários para o conforto dos usuários. Dados representados no ambiente gráfico do método foram transportados para um ambiente computacional, o que possibilitou a aferição estatística da freqüência do comportamento e sua correlação com os atributos. Os resultados estatísticos da aplicação do método indicam uma possível hierarquia entre os atributos estudados e sua correlação com o desenho do objeto. This article is concerned with the development of a graphical method, based on a configurational model, capable of representing simultaneously the waiting conditions and the users’ behavior at bus stop shelters. Through the observation of positioning it was possible to describe physical factors – named attributes – that are considered relevant for their comfort. The data represented in the method have been transported to a computational environment, thus allowing the statistic gauging of the behavior frequency and its correlation with the attributes. The statistical results of the application of the method indicate a possible hierarchy among the attributes that were investigated and their correlations with the object design.Este artigo trata do desenvolvimento de método gráfico, apoiado em um modelo configuracional, capaz de representar, simultaneamente, atributos funcionais de conforto e comportamento de usuários em abrigos de ônibus. A partir da avaliação das condições de espera (posicionamento) dos usuários, pôde-se definir fatores físicos – denominados “atributos” – prioritários para o conforto dos usuários. Dados representados no ambiente gráfico do método foram transportados para um ambiente computacional, o que possibilitou a aferição estatística da freqüência do comportamento e sua correlação com os atributos. Os resultados estatísticos da aplicação do método indicam uma possível hierarquia entre os atributos estudados e sua correlação com o desenho do objeto

Simulação de visibilidade e oclusão em quarteirões históricos: análise comparativa dos softwares Arcgis, Cityengine e Cityzoom

A equilibrada coexistência entre novas construções e conjuntos históricos costuma ajudar a preservar ambiências urbanas e a reforçar o protagonismo de edifícios de inegável valor plástico e cultural. Muitas vezes, restrições construtivas originadas em descrições subjetivas do espaço urbano geram excessos indesejáveis como a redução da atratividade de investimentos e a estagnação das relações sociais e econômicas existentes nestes lugares. Nos dias de hoje, ferramentas computacionais e tecnologias de visualização podem ser utilizadas para aumentar a percepção sobre limiares de interferência visual de novas construções sobre edificações históricas e, se criteriosamente utilizadas, podem contribuir para subsidiar a análise objetiva de impactos urbanísticos conferindo celeridade ao licenciamento das novas construções. Modelos computacionais podem ser utilizados para descrever, numérica e graficamente, espaços oclusos de áreas históricas e “mapear” a interferência de novas edificações. Tecnologias utilizadas para edição de projetos de arquitetura hoje disponíveis não oferecem este mapeamento: este artigo compara o desempenho de ferramentas computacionais que utilizam conceitos elementares de oclusão e visibilidade na aferição de impactos visuais urbanos. A comparação tem por objetivo diferenciar características funcionais destas ferramentas para representar e mensurar espaços dentro e fora dos campos visuais de transeuntes. O trabalho se divide em quatro partes. A primeira parte descreve os modelos conceituais de oclusão e visibilidade e suas aplicações computacionais em três softwares escolhidos para a análise comparativa: ArcGIS, CityEngine e Cityzoom. A segunda parte apresenta os métodos utilizados pelos três softwares para simulação e mensuração de “envelopes oclusos” em quarteirões históricos. Os métodos são testados, na terceira parte, em estudo de caso constituído por quadras do Centro Histórico da cidade de Pelotas - RS. Os resultados obtidos mostram diferenças entre modelos de dados: ArcGIS e CityEngine computam as partes visíveis dos volumes existentes, enquanto Cityzoom computa volumes virtuais em oclusão. Se os três softwares analisados contribuem para a aferição do impacto de novas edificações em ambiente urbano contendo edificações históricas, o software Cityzoom permite a modelagem e mensuração automática, conferindo maior rapidez de resposta em relação aos dois outros softwares.Adequate coexistence between new buildings and historic buildings usually favours historical heritage and help to reinforce the protagonist role of buildings with acknowledged plastic and cultural value. Often, urban regulations constraints originated in subjective interpretations of the urban environment do generate undesirable excesses thus reducing investments and freezing the development of existing social and economic networks. Computational tools and visualization technologies can nowadays be used to enhance the perception about the positive and negative visual interference of new buildings on historical sites and, if judiciously used, can contribute to the objective assessment of urban visual impacts. Computational models can be used to numerically and graphically describe occluded volumes and to "map" the interference of new buildings in preservation areas. Available technologies conventionally used for architectural design do not offer this mapping functionality but CIM (City Information Modelling) software do. This article compares the performance of CIM tools using elementary concepts of occlusion and visibility to measure visual impacts of urban scenarios. The comparison aims to differentiate functional characteristics of these tools to represent and measure spaces within and outside the visual reach of pedestrians. The work is divided into four parts. The first part describes the conceptual models of occlusion and visibility and their computational applications in three software chosen for comparative analysis: ArcGIS, CityEngine and Cityzoom. The second part presents the methods used by the three software for simulation and measurement of "occluded envelopes" in preservation areas. The methods are tested, in the third part, in a case study consisting of blocks located in the Historical District of the city of Pelotas, Brazil. The assessment revealed differences between data models: ArcGIS and CityEngine compute the visible parts of existing volumes while Cityzoom computes virtual occluded volumes. While the three analysed software contribute to the impact assessment of new buildings, Cityzoom enables the automatic modelling and measurement of virtual occluded volumes, thus offering the user a faster assessment than the two other software.  &nbsp

Classificação Orientada ao Objeto com o Uso de Imagens Sintéticas

Orbital images with high spatial resolution started to be used fairly recently, at the beginning of this century. New techniques had to be developed as to adjust required data for digital classification procedures. The academia is engaged in the development of these techniques since orbital images were available whereas municipal administrations, in general, did not make significant progress. This lack of knowledge has generated sheer difficulties to some administrations to specify needed images for further analytical work. One example of this problem is the purchase of synthetic merged images with no awareness that sensors work with specific bands representing ranges of the electromagnetic spectrum, an essential component of the process of pattern recognition. This study investigate the possibility of using synthetic images in the digital classification processes. Processes of object-oriented classification were compared to the pixel by pixel process classification, utilizing transformed images. Methods of post-classification based on the filtering of the product of classification are proposed (GIS procedure). All methods investigated were quantified in order to estimate the viability of using synthetic images of Quick-Bird sensor for identifying features of the urban environment. These procedures aim to contribute to urban studies, especially in the automated surveying of the urban morphology.Pages: 1363-137

Análise da acessibilidade urbana para o planejamento da urbanização de interesse social

An analysis of housing issues in the city of Canela (RS, Brazil) has been made in 2008 as part of the development of the Master Plan for Housing. The present paper deals with one component of this analysis, which is the assessment of urban accessibility for low-income population, and its consequences on the treatment of the problem of current shortage of low-income housing and the future demand from population growth until 2020. A three steps method is applied: (i) urban mobility is assessed and mapped on the basis of the road system and the routes of public transport; (ii) accessibility to different urban services, such as public education and health, recreation, consumption and jobs are measured and mapped considering the location of urban facilities, population distribution divided by income and age, and urban mobility; (iii) one map for urban accessibility is produced as a result of the weighted combination of accessibility to different urban facilities. This final urban accessibility map is then overlayed to empty urban lots with size and land value appropriate to low-income housing, and a simulation of their development over the future has been made. The lots with higher accessibility were selected, and the impact of urban development was assessed on the capacity of education facilities. Based on this study, we made some preliminary suggestions for widening places in some schools, the need for a new education facility (location and size) and the extension of public transport for an area with low accessibility.<br /