Generative Design in Architecture
Belinda Torus, BArch, Student of SMArchS
Design and Computation Unit, Faculty of Architecture, Yildiz Technical University, Istanbul, Turkey.
In this study, the generative design in housing is characterized through the utilization of shape grammars. The functions and the relations within a chosen housing typology are described and different types are produced through the defined relations. Three main constraints are the number of inhabitants (room numbers and sizes), the number of storeys and the main module. In this case, cube is selected as the main module. Mardin is selected as a region to be focused on because of its grammatical housing morphology. Different colors are given to different functions; kitchens, living spaces, rooms, bathrooms, semi-open spaces and open spaces. Different types and variations are produced computationally, and by using this method, it is aimed to integrate the customers to the generative design process. This method is likely to emphasize variation and personalization and make a start to mass customization.
“Generative design is a design methodology that differs from other approaches insofar that during the design process the designer does not interact with materials and products in a direct (“hands-on”) way but via a generative system.”  In this study generative design is used via shape grammars. Shape grammars are generative grammars which new shapes can be created by an initial shape, shape elements and production rules.  New shapes are generated using production rule or rules. Analyzing a house typology through shape grammars is also reasonable as well as generating new ones similar to Birgul Colakoglu’s dissertation for “hayat” houses. 
Parallel grammars are also used in which two or more grammars work together simultaneously.  Jose P. Duarté’s study for Malagueria Houses is one of the examples of parallel grammar.  In Malagueria Houses Duarté used Alvaro Siza Vieria’s grammar and new grammar together. Another property of this study is using mass customization and computation.
Mass customization and mass personalization is based on the variations of a design while mass production is built on the idea of serial repetitions in order to decrease the cost. In the twentieth and twenty-first century the paradigm shifts from mass production to mass customization by the help and development of digital technologies. Mass customization becomes one of the most “popular” methods in decreasing the cost. Variations are used instead of repetitions and different types within a language are created. The places, that have repetitive functions like houses, dormitories, offices etc., can be mass customized.
Figure 1 - Jose P. Duarté - Malagueria Housing
In this study generative design method of shape grammar is utilized for housing design. Mardin, having a grammatical architecture in original is chosen as case study for this project. The study is based on Prof. Fusun Alioglu’s dissertation on Mardin houses  and Hakan Ozbek’s master thesis on shape grammatical analysis of Mardin morphology. 
Mardin is a city in the south eastern region of Turkey. The old city is located on a sloping terrain looking towards the Mesopotamian Plain. Semi-open spaces “eyvan” and “revak” have developed under the effect of climate and play an important role in the perception of the city. The open spaces like courtyards, gardens, terraces and streets enclosed by walls give the void effect. The scenery of Mesopotamian Plain and the orientation play an important role in the configuration of these units. The places cause different effects according to their inclinations and location.
The morphology of the city is composed of units and their repetitions. The units are approximately 4m*4m (~13ft*13ft) because of the constraints of the masonry building system. All buildings with different functionalities have similar properties, so it is difficult to perceive the function in the general structure. Religious buildings or educational buildings are all composed of basic units.
Another important point is that the morphology of Mardin has evolved in time; developing according to the needs. This formation shows the cultural properties of the city inhabitants.
Figure 2 – Mardin
Crowded large families (adding a unit for the married son and the family expanding), respect (not blocking the view of other houses), conservation (the houses designed such that, terraces of other houses must not be seen) are the main rules for the development of Mardin. Also this formation has developed an organic structure for the city.
The main module -a cube- is one of the constraints, which is derived from the city morphology. Consecutively the number of the rooms, the inhabitants, the storeys will be considered. Large families are common in Mardin, as a result of traditional life-style of the city dwellers. As for the houses that are located on a slope, two or three storied houses are the most common type. Thus are the main limitations for the preliminary design described. However these limitations can be altered during the process, according to the outcome.
The shape grammatical rules in Hakan Ozbek’s thesis are the general rules of Mardin. These rules describe the relations between open (yards and terraces), semi-open (eyvan and revak) and closed spaces. They also describe their relations in the third dimension in related to stairs and stair types. The stairs are important elements because they connect different types of spaces with each other according to the needs.
These rules are function free rules. They are the main rules of Mardin morphology. In a specialized project like housing, new rules must be added. Mardin is on a sloping terrain so the number of stories is selected as two or three. Functions, accepted as additional constraint, are given different colors. Kitchens, living rooms, bedrooms, guestrooms and bathrooms are all given a different coloring. The functional relations are also described without undervaluing the grammatical rules. The shared places like kitchens and living rooms are in the first story, while bedrooms and personal places are in the second and third stories with a semi-open space.
Figure 3 – Legend
The number of people and room numbers are another main constraint for the generation. It is selected as four to eight people in the early generations. Room numbers can vary from two (for parents and two children) to eight (for parents, six children and a guest room).
Cube - 4m*4m
Number of storeys
Number of people
4-8 (Room number: 2-8)
First generations constraints
The generations are made in 3dsMax environment by scripting. In the first generations, abstract models are generated. The two or three storied houses four various number of people with the functional relations and grammatical rules of Mardin are generated. “Random” is also used.
Figure 4 - A1/Three story building
Figure 5 - C3/Two story building
After generating abstract models, plan types for each function are designed so that the abstract cubes can be solidified. For each function various plan types are designed. The plans can be selected individually or can randomly be placed. It is also possible to improve or change the plans.
All abstract generations are done by the scripts which are written according to the constraints, limitations and assumed initial conditions. Later, when transforming the abstract design to a solid form, the abovementioned plans are also taken into consideration and used as parameters in the generation phase.
Integration of customers to the project is provided with an interface for this script. Via this interface, the customer is allowed to enter the parameters like the number of stories, number of people the house is expected to accommodate or the room numbers. Thus ultimate customization is permitted. With the help of this interface and the designer working with the customer, the abstract models or the solid project can be derived in the digital environment at minimum time and financial cost. It is possible to generate different variations with the same limitations. So alternatives can be generated.
After generating the houses or after selecting from the generations, modifications and manipulations can de done. Also with changing limitations and varying the initials new forms can be sought.
Figure 6 – Interface on 3dsMax
This study is the first step of an ongoing project in which generative design method and mass customization techniques will be explored for housing design. In this first section, solutions for housing for four to eight people in houses that have two or three stories is sought. Then with the shape grammatical rules of Hakan Ozbek’s master thesis and some newly defined rules, abstract generations and variations are made. By designing plan types for each function, the generations are solidified. New models and alternatives within the same language are explored.
In the second section, the customer demands are integrated to the design process with the help of the script interface. The next step in the project will be seeking housing typologies for different numbers of people, stories, basic modules and plan types in the limits of Mardin grammar. The aim is to integrate it with the script in order to support mass customization.
More details can be added to the scripts and generations, like the window types and sizes, the wall endings, and the orientations. The script and interface can be improved by these details or according to the needs of the customers by the feedbacks from the customers.
I’d like to acknowledge and thank the academic and research stuff in Design and Computation Unit in Yildiz Technical University, especially my supervisor Assist. Prof. Birgul Colakoglu.
 Fischer, T. and Herr, C. M., (2001), “Teaching Generative Design”, GA2001
 Stiny, G. (1980), “Introduction to Shape and Shape Grammars”, Environment and Planning B: Planning and Design 7:343-351
Colakoglu, B., (2005), “Design by Grammar: an interpretation and generation of vernacular hayat houses in contemporary context”, Environment and Planning B: Planning and Design 32:141-149
 Knight, T.W., (2004), “Interaction in Visual Design Computing”, (http://architecture.mit.edu/descomp/works/KnightInteractInVisDesign.pdf)
 Duarte, J. P., (1999) “Customising Mass Housing: the grammar of Siza's Houses at Malagueira”
 Alioglu, F., (2000), “Mardin Şehir Dokusu ve Evler”, Türkiye Ekonomik ve Toplumsal Tarih Vakfı Yayınları
 Ozbek, H., (2004), “Gelenekselden Türeyen Çağdaş Mardin Konut Yerleşimi”, Master Thesis