Freeform Architecture Research Articles

Construction Material Selection Criteria for Timber Gridshell Application: A Literature Review

Timber gridshells have the potential to be a sustainable and cost-effective solution for long-span applications and free-form architecture. Despite this, their overall use has been limited, and there is a lack of research focusing on their construction materials. This literature review aims to investigate timber gridshells and their construction materials to identify the criteria used in selecting suitable materials for gridshell applications. A review of peerreviewed scientific articles, books, and theses was conducted to gather information on timber gridshells, construction materials used in gridshells, timber used in active bending structures, and building standards. The research findings identified six main factors that are important when selecting a suitable material for timber gridshell application: structural strength and strength grading, bending strength and behaviour, bending strength/bending elasticity ratio, durability, commercial availability, and cost. These findings are also discussed to identify the characteristics that make a material suitable for timber gridshell applications, depending on the gridshell’s context, whether in a tropical or international context. This review serves as a necessary reference for architects and engineers when selecting materials for their timber gridshell projects, providing insight into the selection criteria for construction materials and sharing information on the material properties of suitable timber gridshell materials.

Rationalization of Free-Form Architecture Using Generative and Parametric Designs

Free-form architecture is a prominent trend in contemporary architecture where streamlined geometric buildings are constructed. The main problem in free-form architecture is rationalization, which involves realizing free-form surfaces at a reasonable cost while meeting design requirements. Balancing the design intents and construction costs simultaneously is essential for successful rationalization. This study proposes parametric and generative program flows to balance both requirements efficiently. The suggested parametric program flow, which is based on a mathematical algorithm, classifies a free-form surface into multiple areas, which are favorable to flat, single-curved, and double-curved panels. The proposed generative program flow optimizes the double-curved panels’ area through the integration of Multi-Objective Optimization and Pareto optimality. Designers can select the best design option that fits their design objectives through trade-offs using the results of the program flows. Eventually, more efficient and mindful decisions can be made in the early design process by using the results of this study for successful free-form architecture.

The Space Syntax Characteristics of Spatial Configuration in Frank O. Gehry’s Projects

Frank O. Gehry cannot be classified as deconstructivism, but he always pursued a unique language of form and a unique work method. His space exhibits the characteristic of distributed spatial composition through division and establishes an organic coupling method through the central area. This paper aims to explore via quantitative data regarding Frank Gehry’s freeform architecture. As a methodology, the spatial syntax was used as a framework for analysis to investigate the characteristics of the internal spatial structure resulting from the morphological characteristics of Frank Gehry's freeform architecture. The result showed that four target buildings show a similar degree of partial integration in each independent space and a high overall degree of integration, indicating that the area’s texture is systematized. In the target buildings, public spaces such as lobbies or exhibitions show a high degree of integration and control, which indicates that the room with solid centrality and surrounding areas are structured with a systematic hierarchy. It was statistically proven that spatial recognition for wayfinding has a higher efficiency in Frank Gehry's architecture, which has a hierarchical spatial composition in a unique form, than in a box-type building. In his projects, the clear perception of the space is considered by forming a hierarchy between the public space and the subspace according to the volume of the area.

Mesh Division Method of Large Span Spatial Structure based on Free-Form Surface

All Free-form architecture has novel and unique shapes, complex and diverse changes, and has become the trend of modern architectural development with its rich shape changes and soft lines. The traditional grid layout method is not applicable to the grid division of free-form surfaces, and how to divide a smooth and beautiful grid is a hot research problem for large-span spatial structures. In response to the above problems, after investigating the current scientific research results at home and abroad, our team proposes a meshing method using the 3D software Rhino platform to solve the problems of uneven meshing of free-form surfaces and low intelligence, and to divide a smooth and beautiful mesh.

Analytical surfaces for architecture and engineering

Geometers have proposed more than 600 analytical surfaces for implementation. The largest number of these surfaces is used in architecture and mechanical engineering. Although digital architecture and free form architecture are now increasingly influencing the design of long-span shell structures and curved buildings, the research and application of analytical surfaces continues on an increasing scale. The purpose of the research is to study the state of affairs in the application of analytical surfaces in the construction and engineering industries and to clarify the classes of surfaces that have found application in the study of physical phenomena or in solving purely mathematical problems, but not used in other areas of human activity. Another goal is to find analytical surfaces promising for application in architecture and mechanical engineering, which are still little known to architects and engineers. It has been established that, as before, designers take new analytical surfaces to implement their creative ideas from well-studied classes of surfaces of revolution, transfer and umbrella, minimal, ruled, wavy surfaces.

Flexural biomimetic responsive building façade using a hybrid soft robot actuator and fabric membrane

The geometrical inflexibility of rigid-body kinetic building façades is disadvantageous in free-form architecture. To address this problem, a gearless, lightweight, and geometrically flexible daylight-adaptive shading façade module is proposed by hybridizing gripper-shaped pneumatic elastomer and shape memory alloy (SMA) actuators. The compliant inflation mechanism and thermomechanical response of the bias SMA actuation achieved flexural morphology of the stretchable fabric skin and a maximum opening area ratio of ∼20%. Design feasibility, stable mobility, and structural endurance were identified through performance simulation and material testing, followed by operation tests with full-scale prototyping. This paper presents an advanced architectural application of soft robotics technology and smart material. Our findings expand the knowledge on bio-inspired designs and construction processes in climate-responsive building.

Three-Dimensional Printing of Highly Conducting PEDOT: PSS-Based Polymers

Abstract Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) is one of the most successful conducting polymers for electronic applications. Most commonly, the spin coating process is used to fabricate PEDOT:PSS thin films from an aqueous solution, yet it is unsuitable for fabricating complicated two-dimensional (2D) structures. Extrusion-based additive manufacturing (AM) processes have been investigated for 3D printing PEDOT:PSS-based polymers with free-form architecture. However, such methods imply strict requirements on the rheological properties of materials and, as a result, have limited choices of appropriate materials. In the past, additives have been added to improve the 3D printing processability of PEDOT:PSS materials, which, however, usually deteriorate the electrical conductivity. This article reports a new type of PEDOT:PSS material capable of addressing the previously listed challenges and characterized by high processability and electrical conductivity (72 S/cm). In addition, a novel extrusion-based AM technology, electrostatically-assisted direct ink writing (eDIW), is investigated for printing materials containing PEDOT:PSS. The eDIW method prints lines at micro-scale resolution at an ultra-high speed (1.72 m/s). This combination is often deemed impossible in the framework of classical extrusion-based AM techniques. This work lays the foundation for future explorations of applications of PEDOT:PSS-based conducting polymers in fields that require superb properties and custom geometry, which were conventionally impossible.

Development of Variable Side Mold for Free-Form Concrete Panel Production

With the increase of free-form architecture, many studies have been conducted for producing free-form Concrete Panels (FCP), but there are still areas that are lacking in terms of the technological aspect. In particular, as free-form panels are produced by hand, the precision of the shapes is low and cost and time are high. FCP production equipment was developed to resolve this. In this study, the variable side mold for FCP production used in side control equipment among FCP production equipment was developed. Variable side mold is equipment that satisfies five requirements to configure the form of FCPs. The variable side mold is made with steel plates so that it can withstand the side pressure of concrete. As a result, the material has a uniform thickness throughout and is molded to the desired shape. Therefore, in order to verify this, the panel was manufactured as a variable side mold to compare the side form with the designed form through 3D scanning and quality inspection to check for errors. As a result, there was a 0.276 mm mean difference for both ends of the panel and the central part, and it was therefore verified through t-test that errors occurred within the allowed margin of 95% confidence level.

Surfaces of congruent sections of pendulum type on cylinders with generatrix superellipses

In 1972, I.I. Kotov proposed to separate the surfaces of congruent sections into a separate class and to include the surfaces of plane-and-parallel translation, surfaces of revolution, carved surfaces of Monge, cyclic surfaces with a generatrix circle of constant radius, rotative, spiroidal, and helical surfaces in it. The aim of the research is to obtain generalized parametric equations of surfaces of congruent sections of the pendulum type on right cylinders with plane-and-parallel translation of movable rigid superellipses. Analytical geometry methods are used. Computer systems MathCad and AutoCAD are applied to visualize surfaces. The results consist in the derivation of parametric equations of the studied surfaces in a general form convenient for the use of computer modeling methods. The technique is demonstrated on five examples with congruent mobile superellipses. The possibility of using obtained surface shapes in parametric architecture, free-form architecture, and in shaping of the surfaces of some technical products is noted.

생체모방시스템에 기반한 디지털 제작특성에 관한 연구 - 디지털 건축에 나타난 생체모방 디자인의 적용사례 중심으로 -

Biomimicry is the unity of human potential as a way of finding innovative ideas and inspiration from nature and finding ways to solve problems. In the field of architecture, biomimicry can be seen to affect overall engineering, such as architectural planning and design, and building systems. In this study, academic data, dissertations, and specialized literature are reviewed on the status of technology development and promotion using biomimicry. In addition, we examine the types and concepts of production methods according to the development of digital technology, and examine the trends and utilization of digital production processes. The case selection is based on the design of the application of the principle of ecological imitation in modern buildings from the mid-1990s when digital techniques were applied to the 2020s and the design with its meaning is determined, and the results are as follows. First, it is expected to provide a better life by introducing the expressive characteristics of biomimicry such as morphology, technology, and system. Second, digital technology is applied to efficiently implement non-linear free-form architecture. Third, as a result of analyzing the characteristics of the digital production type, it is expected that 3D printing technology and robots will increase in popularity in the construction, engineering, and architecture fields in the future.

Caustics of developable surfaces

While considering a mirror and light rays coming either from a point source or from infinity, the reflected light rays may have an envelope, called a caustic curve. In this paper, we study developable surfaces as mirrors. These caustic surfaces, described in a closed form, are also developable surfaces of the same type as the original mirror surface. We provide efficient, algorithmic computation to find the caustic surface of each of the three types of developable surfaces (cone, cylinder, and tangent surface of a spatial curve). We also provide a potential application of the results in contemporary free-form architecture design.

Computational design of weingarten surfaces

In this paper we study Weingarten surfaces and explore their potential for fabrication-aware design in freeform architecture. Weingarten surfaces are characterized by a functional relation between their principal curvatures that implicitly defines approximate local congruences on the surface. These symmetries can be exploited to simplify surface paneling of double-curved architectural skins through mold re-use. We present an optimization approach to find a Weingarten surface that is close to a given input design. Leveraging insights from differential geometry, our method aligns curvature isolines of the surface in order to contract the curvature diagram from a 2D region into a 1D curve. The unknown functional curvature relation then emerges as the result of the optimization. We show how a robust and efficient numerical shape approximation method can be implemented using a guided projection approach on a high-order B-spline representation. This algorithm is applied in several design studies to illustrate how Weingarten surfaces define a versatile shape space for fabrication-aware exploration in freeform architecture. Our optimization algorithm provides the first practical tool to compute general Weingarten surfaces with arbitrary curvature relation, thus enabling new investigations into a rich, but as of yet largely unexplored class of surfaces.

Design and fabrication of multi-patch elastic geodesic grid structures

Elastic geodesic grids (EGG) are lightweight structures that can be deployed to approximate designer-provided free-form surfaces. Initially, the grids are perfectly flat, during deployment, a curved shape emerges, as grid elements bend and twist. Their layout is based on networks of geodesic curves and is found geometrically. Encoded in the planar grids is the intrinsic shape of the design surface. Such structures may serve purposes like free-form sub-structures, panels, sun and rain protectors, pavilions, etc. However, so far the EGG have only been investigated using a generic set of design surfaces and small-scale desktop models. Some limitations become apparent when considering more sophisticated design surfaces, like from free-form architecture. Due to characteristics like high local curvature or non-geodesic boundaries, they may be captured only poorly by a single EGG.We show how decomposing such surfaces into smaller patches serves as an effective strategy to tackle these problems. We furthermore show that elastic geodesic grids are in fact well suited for this approach. Finally, we present a showcase model of some meters in size and discuss practical aspects concerning fabrication, size, and easy deployment.

Development of 3D Concrete Extrusion Nozzle for Producing Free-form Concrete Panels

There has been an increase in demand for free-form building through the development of advanced technologies, and the fourth industrial revolution has become a worldwide trend, thereby changing the construction industry. In particular, in the case of the free-form architecture sector, development of 3D printing technologies has been ongoing for construction automation. According to such trends, this study develops an FCP production equipment using 3D printing technologies. The FCP production equipment in this study is made up of mould equipment and 3D printer. It is different from existing 3D printing technologies so in this study 3D concrete extrusion nozzle must be developed for producing FCP. Basic design suitable to such requirements is proposed. Applicability of the proposed design is checked and the nozzle form is concretized to draft the final drawing. In this study, slit-type opening and closing device for accurate extrusion stoppage of concrete and screw-type nozzle for adjusting pressure and extrusion speed were applied for the nozzle. This is expected to be innovative technology for the FCP production sector.

3D Bioprinting Strategies for the Regeneration of Functional Tubular Tissues and Organs.

It is difficult to fabricate tubular-shaped tissues and organs (e.g., trachea, blood vessel, and esophagus tissue) with traditional biofabrication techniques (e.g., electrospinning, cell-sheet engineering, and mold-casting) because these have complicated multiple processes. In addition, the tubular-shaped tissues and organs have their own design with target-specific mechanical and biological properties. Therefore, the customized geometrical and physiological environment is required as one of the most critical factors for functional tissue regeneration. 3D bioprinting technology has been receiving attention for the fabrication of patient-tailored and complex-shaped free-form architecture with high reproducibility and versatility. Printable biocomposite inks that can facilitate to build tissue constructs with polymeric frameworks and biochemical microenvironmental cues are also being actively developed for the reconstruction of functional tissue. In this review, we delineated the state-of-the-art of 3D bioprinting techniques specifically for tubular tissue and organ regeneration. In addition, this review described biocomposite inks, such as natural and synthetic polymers. Several described engineering approaches using 3D bioprinting techniques and biocomposite inks may offer beneficial characteristics for the physiological mimicry of human tubular tissues and organs.

Freeform Architecture Design and Construction Process using Construction IT

Freeform Architecture Design and Construction Process using Construction IT

Optimal design criteria for form-finding of double-curved surfaces

The development of new digital design tools and fabrication technologies stimulated a large research interest in the design and construction of free-form architecture. Free-form architecture indicates the symbolic act of freeing architecture from the limitations of pure form. During the form-finding process, the priority is on identifying the geometry that enables the optimum force flow within the structure.This study focuses on the problem of the form-finding problem of concrete double-curved surfaces. First, a suitable form-finding optimization framework to optimize shell surfaces based on the surface Stress Density method is established. This framework is based on the use of different software such as Rhinoceros, Grasshopper, and Matlab. The stress density method is chosen because it allows obtaining an optimized shape starting by few parameters: the geometric characteristics of the model, the surface density factor and the magnitude of the load. In a second step, the study is focused on a single panel of the structure. Structural analyses of this panel are carried out using the commercial finite element software SAP2000 to demonstrate that it is a shape resistant structure. Finally, a new production process for concrete double-curved surfaces is presented showing a prototype at a small scale. This process is trying to satisfy the needs of new shapes within architectural design. The proposed solution is the improvement of an existing flexible mould formwork technology and represents the first attempt to reach a reusable, reconfigurable and affordable procedure.

박물관의 비정형건축형태분류와 전시공간과의 융합상관성 고찰 - 네덜란드, 독일, 싱가포르를 중심으로 -

본 연구는 박물관 비정형건축형태가 늘어나고 있는 현시점에서 학술적 건축형태계보에 관한 패러다임의 변화를 초래하고 있으며 이에 따른 전시공간에 미치는 영향에 관한 유무의 논증이 요구되어 진다. 따라서 선행되어야 하는 단계로서 비정형 건축형태와 전시공간과의 상관관계를 검증하기 위해 최근 2000년 이후 다양한 박물관 설립 또는 재개관한 사례의 현황분석을 통한 실질적인 비정형 형태의 경향을 파악한다. 이에 전시공간이 관람자의 공간체험에 더욱 효과적인가를 유추하기 위해 비정형건축과 전시공간과의 관계성에 대한 결론을 도출하는데 본 연구의 목적이 있다. 연구방법 및 결과는 다음과 같다.BR 첫째, 박물관의 비정형건축 형태적 개념 및 건축형태의 분류에 관한 문헌조사와 선행연구의 고찰을 통해 기준을 정립하여 도입하였다.BR 둘째, 싱가포르, 독일, 네덜란드 등을 직접 방문하여 사례 고찰을 통해 비정형 건축형태와 전시공간의 현황과 특성을 고찰하였다. 이때 Kare Vollers의 비정형 형태기준을 차용하여 분석을 하였다.BR 셋째, 비정형건축형태와 전시공간과의 관계성을 증명하기 위해 Kare Vollers의 비정형 형태기준과 비정형 전시공간을 중심으로 사례별 크로스 체크하여 결과를 도출하였다. 연구 결과의 내용은 다음과 같다.BR 첫째, 비정형건축형태의 EX(Extruder)(angle, ortho)와 전시공간 사선형은 유의미한 상관성을 가진다. 이는 싱가포르보다는 네덜란드와 독일에서 92.3% 명확하게 검증되었다. 반면, 전시공간 곡면형은 불명확한 관계성을 보이며 싱가포르 경우 RO(Rotor), FR(Free Shaper), TW(Twister) 등을 통해 곡면형 관계성을 가진다. 둘째, 비정형 건축형태와 전시공간의 사선 및 곡면형이 복합적 형태조합을 가진다. 특히 N-02, G-02는 융합된 형태로써 EX를 기본적 가지며 부분적 다양하게 형태를 함유하여 비정형의 복잡함을 유도하였다. 이와같이 비정형 형태는 다양한 조합으로 무한정의 변형이 가능하며 이를 대응하기 위해 다각도에서의 융합적 접근이 요구된다.BR 차후 본 연구를 기반으로 박물관의 비정형 건축형태와 전시연출디자인과의 관계성 유무를 논증하고자 한다.

Visual smoothness of polyhedral surfaces

Representing smooth geometric shapes by polyhedral meshes can be quite difficult in situations where the variation of edges and face normals is prominently visible. Especially problematic are saddle-shaped areas of the mesh, where typical vertices with six incident edges are ill suited to emulate the more symmetric smooth situation. The importance of a faithful discrete representation is apparent for certain special applications like freeform architecture, but is also relevant for simulation and geometric computing. In this paper we discuss what exactly is meant by a good representation of saddle points, and how this requirement is stronger than a good approximation of a surface plus its normals. We characterize good saddles in terms of the normal pyramid in a vertex. We show several ways to design meshes whose normals enjoy small variation (implying good saddle points). For this purpose we define a discrete energy of polyhedral surfaces, which is related to a certain total absolute curvature of smooth surfaces. We discuss the minimizers of both functionals and in particular show that the discrete energy is minimal not for triangle meshes, but for principal quad meshes. We demonstrate our procedures for optimization and interactive design by means of meshes intended for architectural design.

Form Follows Force: A theoretical framework for Structural Morphology, and Form-Finding research on shell structures

With the springing up of freeform architectures, the key problem to structural engineers is to generate structural forms with high structural efficiency subject to the architectural space constraints during the conceptual design process. In this research, a theoretical framework for Structural Morphology has been proposed, that provides an effective solution to the problem. To enrich the proposed framework, systematic Form-Finding research on shell structures is conducted.