FRACTAL BASED GENERATIVE DESIGN FOR HARMONY BETWEEN OLD AND NEW
Prof. Dr. Gülen ÇAGDAŞ
Head of Architectural Design
Division, Faculty of
Architecture, Coordinator of Architectural Computing Master
Program, Institute of Informatics, Istanbul
Technical University, Istanbul, Turkey.
email:cagdas@itu.edu.tr
BArch. Gaye GÖZÜBÜYÜK
Institute of Science and Technology, Istanbul
Technical University,
Architectural Design Master Program, Istanbul, Turkey
email:gayegozubuyuk@yahoo.com
Dr. Özgür EDİZ, Instructor Department
of Architecture, Uludag University, Bursa, Turkey.
Abstract
In this paper, a computational design model based on
the fractal dimension will be presented. Fractal dimension is used as a means
of capturing the pattern appropriate at the compositional configuration of a
historical architectural language and generating new forms, which will ensure
the continuity of this language. In the first stage, architectural
characteristics of a district with special architecture will be defined by
calculating fractal dimensions in different levels. In the second stage of the
model, this fractal values are used as input in computer program for producing
form alternatives for the new buildings that will be designed in such places.
This twostaged model, which is generated for the purpose of providing harmony
between new and old, is applied to Chora, which is an important historical
settlement of Istanbul. The generation process describes how to derive a
compositional configuration from other forms with different dimensions, which
can be generated by changing fractal dimensions.
1.
Introduction
Computer
supported design systems can generate different images during the early design
process and provide useful inputs when searching for alternative forms of
architectural design products. It is aimed that the generative approach which
is used in this study will be used for supporting the creativity to produce
architectural forms based on an existing architectural pattern. Providing harmony in architectural design
between old and new is a great problem for cities like Istanbul, which are
growing around historical core. New buildings must be both unique and conformed
to the proportional feature of the old buildings. In this way the proportional
characteristic of original pattern of a historical environment or of a special
environment is protected. In the development of this approach, the following stages
have been carried out:
2. Fractal Geometry and Architecture
Geometry is the fundamental of the architectural
discipline. It is a tool for describing thoughts of a designer for creating
architectural product itself and its two and tree dimensional representations;
drawings and models. For the purpose of creating architectural objects Euclid
geometry has been used for ages. According to Bovill the reason of the
influences of Euclid geometry being so strong in architecture is that
architectural forms are manmade [2]. The researchers describe the relationship
between Euclid geometry and architecture with the effects of massproduction in
architectural design because the forms of building elements, which are produced
with mass production depends on Euclid geometry [3].
On the other hand the architectural design
approaches based on nature revealed the effects of fractal geometry in
architecture. Fractals  which were introduced by Benoit Mandelbrot in 1980s
for describing the forms of natural objects, like coasts, mountains – have appeared
in architecture with the details from a larger scale to the smaller one [4].
Although there are many examples, which based
on fractal concept in the history of European, African, Asian and American
architecture fractal geometry is begun to be used consciously in architecture with
the new design approach in computational architectural design. Fractals could
be represented by generative algorithms in computer with their major
characteristics; developing through iterations, depending on starting
conditions. In this way they could be used for designing forms, structures and
surfaces alternatives [2].
In this study, fractal dimension is
used as a means of capturing the pattern appropriate at the compositional
configuration of a historical language and generating new forms, which will
ensure the continuity of this language:
The aims of this study are:
In the case study, fractal dimension is used in
two ways. Firstly it is used for determining fractal characteristic of a
historical district in Istanbul and secondly it is used within a computer model
for creating new buildings forms, which have the same fractal characteristic
with this place for providing the harmony between old and new. For the case
study, Chora (Kariye) district has been chosen.
Chora
The Kariye neighbourhood is located in the district
Edirnekapi in Istanbul. The word Kariye (Chora) meaning "outside of the
city", or "rural" is derived from old Greek [5]. In Kariye there
are many monuments of the Byzantine and Ottoman periods. Kariye Church (Figure 1),
Tekfur Palace (Figure 2), and Kastoria synagogue are some of these monuments.
Figure 1.Chora church [6] Figure 2. Tekfur Palace
[7]
Chora Church, the symbol of the district is
built on the site of a chapel, which is located outside of the city walls, by
Justinianus. Several additions and repairs, which were made between the years 1315
– 1320, formed the current shape of the building. The mosaics and frescoes
examples in Kariye Church are regarded as the most beautiful of the last period
of Byzantine art. In the surroundings of the church, traditional Ottoman houses
and streets are located. (Figure 3)


The buildings of which
fractal dimension is calculated 

The building in the place of
which alternatives are generated 


The buildings in the neighbourhood
of the field study 


Historical buildings in the neighbourhood of the
field study 
Figure
3. Site plan of the Kariye Bostani
Street
3.1.
Kariye Bostani Street
The
reason why this place is chosen for field study is the traditional architectural
pattern of the street. There are both the examples of multistorey buildings,
which were built after 1950’s and of low storey buildings of traditional
Ottoman Architecture near the street. Although the pattern of the street is
protected in a large scale, the effects of chaotic architecture of the
environment can be seen on the street.
Figure
4. The Protected
side’s of the street
Figure 5. The Protected side’s Silhouette of the
street
On the both side of the Kariye Bostani
Street traditional Ottoman houses are located. (Figure 4, 5, 6) All the houses
on the one side of the street are two or three storied wooden row houses and
have a bow  window (cumba) on each façade.
(Figure 4, 5) On the other hand there are five or more storied concrete
buildings, which are not in a harmony with these buildings, on the other side
of the street. (Figure 7, 8)
Figure 6. The other side of the street
Figure 7. The other side’s Silhouette of the street
In this study, a design model is
suggested for providing proportional harmony between the forms of traditional
buildings and new buildings and for protecting the street pattern.
Figure 8. 3D model of the current situation of the
Kariye Bostani Street
4. Generating new form alternatives
in Kariye Bostani Street
In the generation process of new
form alternatives a computer model has been used [8, 9]. The model starts with
the analyses about the Kariye Bostani Street. Fractal dimension takes the most
important role in the analyzing level. For defining characteristic features of
the architectural language of the Kariye Bostani Street, fractal dimensions in
plan, silhouette and building scale have been calculated [10]. The fractal values
obtained by using Bovill’s Boxcounting method have been used as inputs in the
computer program for composing alternative forms on the selected place in the
street. (Figure 9)
With the aim of creating new forms according to
the fractal values of the existing pattern, the place of the corner building
which does not suit with the architectural characteristic of the Kariye Bostani
Street is chosen for the project area.
(Figure 7, 8 building with colour blue) The new form alternatives are
generated in the 18mx18m square shaped project area by defining the number and
dimensions of initial shapes on xy and z axis. Therefore a grid system of boxes was superimposed over the project
area on xy axis [11]. In this way, dimensions of the initial shape have been
defined.
Figure 9. Form alternatives
In the next stage of the generation process two
different initial shapes, a 3mx3mx3m cube and a as 3.60mx3.60mx3m square prism
have been used for obtaining various design alternatives. In the last stage, fractal
dimensions  which are calculated as 1.7 in the settlement scale and 1.2 both
in the silhouette scale and building scale  have been applied to the initial
shape for generating new forms. Finally, these generated form alternatives were
tested on the 3D models of the Kariye Bostani Street and its surroundings,
which were created in virtual environment. (In the first three
alternatives, a 3mx3mx3m cube and in the fourth and fifth alternatives a 3.60mx3.60mx3m
square prism has been used as initial shape.)
4.1 Form
Alternatives
Figure 10. Alternative 1
Table
1. Fractal values and the number of cubical units on x, y, zaxis, which have
been used in
Alternative
1
Fractal
dimension 
Cubical units on the x axis 
Cubical units on the y axis 
Cubical units on the z axis 
1.7 
6 
6 
4 
Figure 11. Alternative 2
Table
2. Fractal values and the number of cubical units on x, y, zaxis which have
been used in Alternative 2
Fractal
dimension 
Cubical units on the x axis 
Cubical units on the x axis 
Cubical units on the x axis 
1.7 
6 
6 
5 
Figure 12. Alternative 3
Table 3. Fractal values and the number of cubical
units on x, y, zaxis which have been used in Alternative 3
Fractal dimension 
Cubical units on
the x axis 
Cubical units on
the x axis 
Cubical units on
the x axis 
1.2 
6 
6 
5 
Figure 13. Alternative 4
Table 4. Fractal values and the number of box units on
x, y, z axis which have been used in Alternative 4
Fractal
dimension 
Box units
on the x axis 
Box units
on the y axis 
Box units
on the z axis 
1.7 
5 
5 
5 
Figure 14. Alternative 5
Table
5. Fractal values and the number of box units on x, y, zaxis which have been
used in Alternative 5
Fractal
dimension 
Box units
on the x axis 
Box units
on the y axis 
Box units
on the z axis 
1.7 
5 
5 
5 
5. Conclusion
One of the significant problems in
architectural design is providing harmony between old and new. Fractal concepts
have been come to use in many ways, both consciously and unconsciously, in the
field of architecture.
In this study, by relying on the fractal
dimensions of an existing architectural pattern a generative design approach
has been suggested which can be used in the process of supporting creativity in
the creation of new forms and for testing harmony between old and new .By using
the fractal dimensions of elements found in a shape library belonging to the
relevant architectural language, this approach may show the way to the creation
of architectural forms which will ensure the continuity of the pattern.
Using digital technologies while searching for
alternative forms in the conceptual design phase is a new approach based on the
development of new technologies. Using digital media as design media gives the
designer the opportunity to expand his/her imagination and innovations.
By placing the three dimensional form
alternatives in the settlement model, harmony has been tested with the existing
architectural language.
References
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