Section as Form Generator under Digital Environment
Prof. Shuenn-Ren Liou, BSc, MArch, DArch
Department of Architecture, Tunghai University, Taichung, Taiwan
Given the development of digital design concepts and technologies, architects are confronting a new territory of architectural form generation. Two significant themes have emerged. One has to do “post-generation systems” dealing with the analysis of existing precedents and the derivation of new instances. The other has to do with “dynamic forces” dealing with form abstraction based on process and movement. This paper examines how section may be used as form generator under digital environment. Two sets of design experiments are developed and conducted to explore the aforementioned two themes. The concept and logic underlying the methodology of the two design experiments are discussed. The processes and the products are presented. The attributes characterizing dynamic forms are also identified on the basis of the findings acquired from the experiments.
Many scientific approaches to the problem of form generation in architectural design have progressed greatly since the second half of the 20th century. Along the progression, two significant themes have emerged. One has to do “post-generation systems” which deals with the analysis of existing precedents and the derivation of new instances. Noteworthy among them is the shape grammar formalism initiated by George Stiny and James Gips.  Many known architectural precedents are employed as subjects for study such as Andrea Palladio , Frank Lloyd Wright , and Giuseppe Terragni . The other has to do with “dynamic forces” which deals with form abstraction based on process and movement. Noteworthy among them is the animate form proposed by Greg Lynn.  The purpose of this paper is to explore how section may be used as form generator under digital environment. Two sets of design experiments are developed and conducted in response to the aforementioned two themes. Experiment I places emphasis on the design from known to new and Experiment II on the dynamic form making.
2.1 The process of analysis and generation
The first set of experiment addresses the theme of design from known to new. A method for analysing the morphological structure of an existing building and generating the new form is developed on the basis of “structural section.” The process of analysis and generation consists of three sequential steps: the derivations of the basic form, the composite form, and the plastic form.
Step 1: The Basic Form
The derivation of the basic form is based on the analysis of a historic sawmill building. An interesting structural difference is found in the longitudinal cross section. The idea of “Difference” is extended to establish the form generation mechanism. (Recall Derrida’s use of “Différance” for the discussion on time and space.) An operation called “Differential Generation” is applied to generate the basic form as shown in Figure 1.
Figure 1. Basic Form Generation
The basic form is placed within the framework of another existing building (a small sawmill attached to the historic one). Their spatial and inter-relations are created through the application of an operation called “Constructive Linkage.” The composite form is generated as shown in Figure 2.
Figure 2. Composite Form Generation
Step 3: The Plastic Form
As shown in Figure 3, the composite form is made up of 27 section frames. Each section frame is in turn made up of a number of straight lines. Many contour shapes of the section frames need to be modified for further processing. Following that, all of the straight lines are transformed into curved lines through the application of B-spline. As shown in Figure 4, the final form is generated through the application of the operation called “Plastic Integration.” Note that each section in the final form consists of four basic spaces and one to three overlaps in-between.
Figure 3. The Composite Form and Its 27 Sections
Figure 4. The Final Plastic Form and Its Sections
2.2 Formal Attributes
The final plastic form is characterized by the overlaps in section. The formation and the shapes of the four basic types of the overlaps are shown in Figure 5.
Figure 5. Basic Types of Spatial Overlaps in Section
Moreover, the combination of the basic types of overlaps provides the sections with a wide variety of spatial morphology as shown in Figure 6.
Figure 6. Sections of the Final Plastic Form
3.1 The process of analysis and generation
The second set of design experiment addresses the theme of dynamic form making. The idea of section is employed as an archetype for abstracting the ostensibly complicated shapes derived through human body movement. In the following experiment, basketball playing is used as the subject for study. As shown in Figure 7, the experiment captures the movement of dribble and represents it in a series of frames of frozen states. Each frame shows that the gesture of the body occupies space in a particular time. The contour shapes of the body gesture are abstracted and superimposed in Figure 8. The overall dynamic form is generated from the accumulation of the application of NURBS on the ever changing shapes of the section through a period of time, as shown in Figure 9.
Figure 7. The Frames Captured in the Movement of Dribble
Connecting all pivot points such
as head, shoulder, elbow, wrist, knee, and ball using PLINE in CAD.
Connecting all pivot points such as head, shoulder, elbow, wrist, knee, and ball using PLINE in CAD.
Figure 8. The Abstraction and Superimposition of the Shapes Derived from Body Movement
Figure 9. The Application of NURBS on the Ever Changing Shapes of the Section
3.2 Sectional Spaces in the Dynamic Form
Five basic dribble movements are recorded and analyzed respectively according to the aforementioned process. Finally five dynamic forms are generated. The sectional spaces in one of the dynamic forms are shown in Figure 10.
Figure 10. The Sectional Spaces at Different Locations of a Dynamic Form
3.3 Formal Attributes
Each of the dynamic forms appears as a longitudinal, curvilinear form with various degrees of folds on surface. In contrast to the traditional geometric form, the dynamic form is characterized by its apparent complexity and continuity. A closer examination reveals that the visual effect of complexity and continuity may result from the following formal attributes.
With respect to complexity, the findings show that the sections of the dynamic form have no recognizable basic shapes such as square, circle, and triangle. They instead are irregular in shape. In addition, the composition of the sections normally lacks of a clear orientation. The ambiguity in orientation is due to the multiple axes underlying the composition’s multiple directions. Moreover, the layers of composition are interweaving. The alternation of the concave and convex surfaces also increases the effect of unbalance. In summary, the complexity of the dynamic form is characterized by the formal attributes like irregular shapes, multiple axes, interweaving layers, and unbalanced composition. (See Figure 11.)
Figure 11. Complexity: Irregular Shapes, Multiple Axes, Interweaving Layers, and Unbalance
With respect to continuity, foldness and smoothness are the two key issues. There are various kinds of folds on the exterior and interior surfaces. Nevertheless, all the folds are determined by size and angle. Smoothness can be realized as the continuous changes of folds within a limited period of time and space. The changes of folds in different depths produce the density of folds on the surfaces of the dynamic form.
Figure 12. Continuity: Foldness and Smoothness
The two design experiments using section as form generator under digital environment are presented above. The first experiment deals with the design from known to new. The idea of “differential generation” is employed for the analysis of the architectural precedent. The “structural section” is applied throughout the three steps of form generation. It is found that the structural section constitutes a good mechanism for understanding the existing spatial structure and, on the basis of the understanding, for creating a new form. The final plastic form is characterized by the four basic types of the overlaps in section. The combination of the basic types also provides the sections with a wide variety of spatial morphology.
The second experiment deals with the making of dynamic form. The idea of “section” is employed as an archetype for abstracting the ostensibly complicated shapes derived through human body movement. The contour shapes of the moving body are captured, abstracted, and represented in a series of frozen sections. The final dynamic form appears as a longitudinal, curvilinear form with various degrees of folds on surface. It is characterized by its apparent complexity and continuity. The problem of complexity can be addressed by the formal attributes like irregular shapes, multiple axes, interweaving layers, and unbalanced composition. The problem of continuity can be addressed by the issues of foldness and smoothness. Smoothness can be realized as the continuous changes of folds within a limited period of time and space.
It's difficult to use the formal principles such as proportion, geometry, axis, symmetry, rhythm, and hierarchy, as applied in classical or modern architecture, to address the problems of the digital-generated free form such as the plastic form in experiment I and the dynamic form in experiment II in this paper. From the above discussion, it is clear that some more adequate terminology (e.g. Greg Lynn’s use of blob) is required. A general framework for describing, understanding, and interpreting the properties of these new forms also needs to be established in the discipline of architecture.
In contrast to section, plan as the generator for new architecture was ever advocated eloquently by Le Corbusier. In his Towards a New Architecture, Le Corbusier stated: “The Plan is the generator. Without a plan, you have lack of order, and willfulness. The Plan holds in itself the essence of sensation. The great problems of to-morrow, dictated by collective necessities, put the question of ‘plan’ in a new form. Modern life demands, and is waiting for, a new kind of plan, both for the house and for the city.” Indeed by tradition architectural research has paid much less attention to section than plan; however, as reflected in this paper, it can be argued that “the essence of sensation,” “the great problems of tomorrow” may exist in Section. It’s about time to call for the development of a new discourse on section as form generator in the new digital era.
This author would like to thank Chi-Kuo Wang and Chi-Bin Chao, two members of the Team of Architectural Morphology at the Department of Architecture, Tunghai University, for their contributions to the above two experiments.
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