The following paper is written for the international conference Game Set and Match II which will be held in march/april 2006 in Delft, The Netherlands. The paper discusses my main graduation topic, namely the parametric design methods to create an architectural environment which handles mass-production of housing blocks.

Abstract
While social housing in the Netherlands is increasingly stimulating user participation, it has little to do with diversity and uniqueness of living. The influence is mostly restricted to cosmetic variety. The identification and uniqueness of a building block is usually determined by the exterior, while the pattern and structuring of the elements of the building block is following very strict rules. The merging of housing for the masses and the uniqueness of the individual in a way that the building block itself represents the unique character instead of the cosmetic skin is a challenge for the design of new urban housing environments.
The aim of this project is inspired on the favelas in Sao Paulo, Brazil. The pattern of these large areas shows an uncontrolled growth of residential units. Although it seems chaotic, living is in fact structured and clear to its residents. The analysis of this pattern of structures has inspired us to develop a modular system of building blocks. The uniqueness and identification is not only present in its cosmetic skin, but also in the arrangement and combination of the building blocks.
The creation of this new environment is based on the method of parametric design in which certain parameters are given before the script is executed. These parameters are mostly derived from essential elements of either the building blocks or the urban context. The script interprets the input parameters to generate a model that fulfills all requirements. The generated results act as a starting point for further design.
The script handles a wide range of structuring elements within a grid. The infrastructural works, green and leisure zones, shopping areas, future development areas and modules for housing are all elements that are generated using the same algorithms but with different input parameters.
Design methods, like presented in the paper, might change the design process and the role of the architect. This generated design of a mass housing environment sets new standards for social interaction and structuring of building blocks in a dense urban setting.


Social Housing
After the Second World War there was a large demand for new social housing areas. Due to new industrial processes it was possible to build new prefab elements. Together with the prosperous economy new housing areas were build in mass production. The tradition of social housing was and still is influenced by functionalism and the economic cost effectiveness of the production process. As a result both the structural elements and the visual outer skin were very similar in those post-war urban environment projects. In the last decades however, a noticeable change has taken place. Future homeowners wanted to be involved in the design process more often and more significantly. They were given the chance to be part of the design process where the architect would translate their opinion into an architectural object resulting in a house-on-demand, unique to the individuals' personal choice. Unfortunately, new urban areas are still being built using the same traditional ideas, which results largely in a very functionalistic approach of repetitiveness. One unit is repeated into a row of identical blocks. This concept is still used in most of the new urban areas. As a result those areas become monotonous in the bare structural geometric composition of each unit. Although new urban environments are more diverse in their visual appearance then in the past decennia, this is only a change in outer skin rather than a change in geometric structure. A rich diversity of colors and materials is used more often to enrich the structure of the building block which supports a visual idea of difference and uniqueness. The identification and uniqueness of a building block as 'mine' or 'yours', is usually determined by the exterior, while the pattern and structuring of the elements of the building block is following very strict rules. This poses a question. While Social housing in the Netherlands is increasingly stimulating user participation, this participation most often is purely cosmetic and has little to do with diversity and uniqueness of living. Although it does enrich the environment in diversity and uniqueness, the building block itself remains the same. However, build environments which do not have any form of structural planning do exist. In most cases, the growth of these areas is uncontrolled and unintentionally. One of these environments is found in the Brazilian favelas.

The favela
The term favela is used in Brazil to describe large areas of shanty towns or slums, and is derived from a species of plant that grows in the hillside of Rio de Janeiro. These hillsides were originally used by freed slaves who first established a community in the end of the 19th century. Although the comparison to slums is often made, a favela is fundamentally different is terms of its origin and location. While slums mostly arise when poorer residents from the countryside come to larger cities in search of work, the favela originated when a large population became displaced. The first favela is considered to be created in 1897 after some 20.000 veteran soldiers were brought to Rio de Janeiro and left with no place to live. Today's favelas originate from the 1970's as a construction boom in the richer parts of Rio de Janeiro attracted many workers from poorer states in Brazil. Heavy flooding in the low level poorer areas also forced a vast number onto the various hillsides. All development on these hillsides is not funded by the state and is characterized by a total absence of numbered streets, sanitation networks, plumbing, electricity or telephone. Residents build new units on the fly without a license or approval and with any material present. As a result this pattern of uncontrolled growth leads to a vast, seemingly chaotic, but yet very structured way of living. The expansion of new building blocks seems to lead to a number of distinct typological elements. These elements are the basic structuring types that constitute the building blocks. The analysis of this pattern of structures has inspired us to develop a modular system of building blocks. The uniqueness and identification is not only present in its cosmetic skin, but also in the arrangement and combination of the building blocks. Although the surroundings and origin of the favelas is not inspiring for Western civilization as a community to live in, the pattern and structure of the construction on the other hand is far more intriguing. The concept of this uncontrolled grown environment compared to the structured way of row housing in new urban areas is the basis for the development of this modular housing project.

Parametric design methods
The applied method for creating this new environment is based on parametric design. Within the parametric procedure certain parameters are given before the script is executed. Essential elements from the client brief are subtracted into parameters in a unified amount of comparable mathematical values. The essential elements are mostly derived from either the building blocks or the urban context. Amount, dimension and orientation are the basic parameters that are used in an urban design where large numbers of elements are required. Together with other non-derived parameters these form the basic starting parameters of the parametric design method. At the start of the script the option is given to set the parameters to suitable values. Once these are set the creating part of the script can be executed. The script interprets the input parameters to generate a model that fulfills all requirements as determined by the parameters. Once the script ends by either reaching all requirements or not being able to continue after reaching certain validation stopping points, it has produced the result. These generated results cannot be qualified as architecture; but act as a starting point for further design. The repetitiveness of the script allows rerunning the sequence many times with different input parameters to generate different results. Since the script does not create a model in which every detail has been constructed, the next phase of the design process will take place manually.

Working of script
The original idea of the script was to create an urban housing environment consisting of modular blocks to provide a favela based pattern. Multiple scripts have been written to provide different aspects of an urban environment. Each script handles a specific range of structuring elements within a grid. All these elements are generated using the same basic algorithm but with different input parameters. The basic algorithm operates as follows.
To place elements on the grid, the script randomly selects a coordinate within the environmental boundary. The retrieved position will then be subjected to a validation process to ensure it is a valid position. The algorithm checks the coordinate for elements that may already occupy the position and dependent on the type of element, accepts or rejects it. If the height coordinate of the position can be raised, and the element present at the given position allows for other elements to be built on top, the system will raise this height coordinate to the first valid position. If the original coordinates are not valid and raising the height coordinate also does not provide a valid point, the algorithm rejects that position. The script will then repeat the sequence and randomly select a new coordinate within the environmental boundary. This validation algorithm ensures no elements are built in or through other elements.

Several subscripts in the main script are present to create elements for different purposes. Within the environmental boundary new areas are created for infrastructure, green and leisure zones, future development, larger shopping malls and office spaces, and modules for housing. Each of the given subscripts allows multiple sets of parameters. For instance it is possible to create two sets of housing modules with different parameters for dimension. The use of different sets is implemented to promote the diversity of the end results.

At first the world space is specified. The second step in the whole sequence is to create infrastructural works. Each set of roads has three parameters; one for the amount of roads, one for the size of a single road element and a parameter for orientation. The general idea behind the infrastructural works is the principle of a growing snake. A road consists of a combination of small square road elements, represented by a grid cell, that together produce a road string. For each set of roads, the starting position for the road string is derived by dividing the world size through the amount of road strings in the set. This coordinate is used for the first road element in a road string. From this starting point onwards each new road element is adjacent to the previous one, but the position relative to its predecessor can vary dependent on a script generated random variable. These growing snakes are searching a path on their own until they reach the environmental boundary. This results in an unpredictable pathway for each road string to be generated. Road elements can never be built on an already existing position. If a road string needs to cross another already existing road string, a crossing is made out of the shared cell.

The following step of the script handles the larger areas for shopping malls, office spaces and areas for future development. Within the environmental boundary the recursive algorithm determines positions and dimensions, derived from the input parameters, to reserve large restricted zones for this purpose. Similarly, areas for future development are generated. These restricted zones can be seen as separate design areas in the whole urban environment. Each set of these areas has parameters for dimension, amount and position. Dimensions can be given either using exact values, or defining a range of values for which the generated space will use a random value between the given limits. By defining the same height of the world for the space, you ensure no other elements will be placed on top of these areas. By setting a height value lower than the world height, you allow other elements to be built on top. With the position parameters it is possible to define an area in the imaginary world where the spaces will to be created. For instance you may want to generate spaces from a set only in a small part of the world.

Green and leisure zones are basically generated in the same way as the restricted zones for shopping malls and offices. A given number of zones is created and marked for leisure activities, such as green zones. Further, empty spaces are created to improve the air and light quality. The zones generated in this phase are taking up the full height of the imaginary plan. This is done to prevent new elements being created on a higher level at that same position. These empty spaces proved to be a considerable asset for the quality and density of the generated environment. Since they act as air vents, and therefore have no mass or borders, they provide open gaps in the density of the vast amount of build modules.

Finally the modules for housing are generated. Each set of modules has parameters for amount and length, width and height dimension. The script first locates a grid coordinate for a module to be placed. If a certain position is already occupied by other elements in the urban environment, the algorithm will raise its base height position until a valid group of grid cells is found. This raise of the base height position only occurs if the located position allows elements to be moved to a higher position. In some cases the environmental boundary does not allow new elements to be placed on higher positions, due to parameter restrictions, and the full height is regarded as occupied by the one single element present at the given position. Consequently, if raising the base height position is allowed, modules can be placed on top of each other, or on top of other existing elements within the environmental boundary. Each module is not only located at a different position, also the orientation of the module varies using a script generated random variable, but is limited to the north-south or an east-west direction, to promote the divers and seemingly chaotic design.

To keep the project within an acceptable time frame certain aspects of the design are restricted. For instance the overlaps of modules that are on top of other objects are not accounted for in constructional reality. To overcome these limitations, the choice is made to manually look into those, and design them in a traditional design process. In a similar way the grouping of modules into single housing blocks, consisting of between two to six modules, the distinction between private and public space, and stairways and elevators are not taken into account within the concept of the script.

The end result of the whole design exercise is a sponge-like constellation of modules. The diversity in positions of the geometrical identical modules result in open passageways, small streets, larger open areas and a vast amount of balconies and gardens. As a result there is a great opportunity for social interaction. To enter a module, you will pass other modules on the way and as multiple modules are opened up through shared stairways, new meeting points are derived instantly. The main goal to design a housing neighborhood where each house is unique in its structural composition through a radical diversity of geometrical constellations provides a way of living in which social interaction is promoted while maintaining each individuals identity through the uniqueness of each unit.

Discussion
Within the quest for computed architecture through generative or other code-based methods there will always be a distinct relation between code and human interaction. A computer or script in itself can not do anything. It needs to be given orders and those orders needs to interpreted by the script which is designed by human. It is not a case of computers taking over the architectural world, resulting in an abundance of architects. The results, however detailed, are still generated as models on which the architect has power and control. No script really understands what architecture or esthetics is. All handlings in a script need to be written and made in such a way they are useful for the given project. The script in itself does not produce architecture; it produces possibilities and general structuring objects. The human interpretation plays a large role in the results of the generated models. Intervention, elimination and adjustments make the final result better from an architectural point of view.

The use of genetic algorithms, cellular automata, parametric procedures and other computer based systems in the design process for architectural purposes raises the question if such results can be produced in a traditional design process. The immense computing power and unemotional skills of a computer handle problems differently as opposed to humans. The complexity and vast amount of data produced by such systems provide a quick optional solution to a given dilemma. The main use of code based systems is not a quest for complexity or elaborate form. It is a method of looking at a problem and using mathematical systems helpful in the process of solving the initial concept. While some results of such systems could in fact be done in a manual design process, speed and amount of data make it practically impossible to do so. The gain of these systems is based on those parameters, whether or not the targeted result has a geometrical complexity or simplicity.
New design methods and concepts might change the design process and the role of the architect. The key is to embed and make use of these systems in practical sense and design.

© Eric Vanderfeesten

Eindhoven University of Technology
Faculty of Architecture, Building, and Planning
Design Systems group
Vertigo - VRT 9.10
P.O. Box 513
5600 MB Eindhoven
The Netherlands


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