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Conference Volume 8884 - Optifab 2013, Julie L. Bentley, Matthias Pfaff; Rochester, New York, USA; October 14, 2013. Copyright (2013) Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited., We present an imaging technique for the 3D-form metrology of optical surfaces. It is based on the optical absorption in fluids situated between the surface and a reference. An improved setup with a bi-chromatic light source is fundamental to obtain reliable topographic maps. It is able to measure any surface finish (rough or polished), form and slope and independently of scale. We present results focused on flat and spherical optical surfaces, arrays of lenses and with different surface finish (rough-polished). We achieve form accuracies from several nanometers to sub-lambda for sag departures from tens to hundred of microns. Therefore, it seems suitable for the quality control in the production of precision aspheric, freeform lenses and other complex shapes on transparent substrates, independently of the surface finish., Sección Deptal. de Óptica (Óptica), Fac. de Óptica y Optometría, TRUE, pub

Rapid developments of both new (digital) fabrication techniques and innovative software facilitate the possibility to design, check and construct objects with great complexity and uniqueness without a large price tag. After new techniques slowly entered the field of architecture, the next step is to apply them in civil engineering to design load-bearing structures, dealing with a large number of load cases, outdoor conditions and strict safety requirements. The application of digital fabrication in civil engineering is examined through a case study: the design of a pedestrian frame bridge made of timber using CNC-milling techniques. In this research a strong focus is on the design, optimisation, detailing and testing of the connections. This research demonstrates that the combination of a reciprocal gridshell structure in combination with interlocking joints (lap joints) is particularly suitable for digital timber fabrication since a stable system can be obtained without the use of fasteners. The uniqueness of all connections and the strong relation between them makes the design process complex. Nevertheless, with the help of digital design tools like Grasshopper and evolutionary it is possible to deal with a large number of parameters with a complex relation between them. Additionally lab tests were carried out to get insight in the shear capacity of notched members. The tests show that the verification method for notched members in Eurocode 5 does not accurately predict the shear strength when hardwood is applied. Additional research on the fracture energy of hardwood is required to propose an improved calculation method. Furthermore, the tests have shown that the application of rounded edges and screws as reinforcement significantly improve the shear capacity of notched members. It is therefore always advised to apply rounded edges, if possible in combination with screws. All in all, the case study has shown that it is poss, Civil Engineering | Structural Engineering

The radical change in architectural design transcends the individuality of design towards multivarious individuation. The immersion of parametric diagrams in the representation of architectural objects leads into a process that could be grasped and manipulated with a high degree of efficiency. Computational advanced design techniques are becoming necessary; therefore new techniques need to be implemented to work on retooling the traditional ways of manufacturing elements. To formulate the problem; Architects, façade engineers and manufacturers need a speculated new solutions and be their liaison for collaboration. Complex designs driven out of parametric potentials are characterized by the various angles and inclinations that form the mullions/sub-construction, which forms the desirable design. Accordingly, having a flexible connection that can provide a full range of proper angles, is requisite. Additive manufacturing also is known as 3D printing, is based on the theory that any object could be synthesized by breaking it down to multilayers that are needed to be laid at the top of each other to form the final object. Metal- Based additive manufacturing has significant growth in the last couple of years, based on the advantages that AM offers, which is producing complex 3D objects directed from CAD data without the need for that careful and detailed analysis that is needed by the other manufacturing processes. A unique collaboration between architects, façade engineers and manufacturers could be achieved by following a whole new aspect, which is how to move from Design to Production. The merge between design and manufacturing could revolutionize the building process of complex buildings. Moreover, the elimination of several constraints, which usually show up in the planning phases. Additively manufactured parts still need some verification to reach the level that the market and the user can accept and trust., Architectural Engineering +Technology

Architecture, Urbanism and Building Sciences

The radical change in architectural design transcends the individuality of design towards multivarious individuation. The immersion of parametric diagrams in the representation of architectural objects leads into a process that could be grasped and manipulated with a high degree of efficiency. Computational advanced design techniques are becoming necessary; therefore new techniques need to be implemented to work on retooling the traditional ways of manufacturing elements. To formulate the problem; Architects, façade engineers and manufacturers need a speculated new solutions and be their liaison for collaboration. Complex designs driven out of parametric potentials are characterized by the various angles and inclinations that form the mullions/sub-construction, which forms the desirable design. Accordingly, having a flexible connection that can provide a full range of proper angles, is requisite. Additive manufacturing also is known as 3D printing, is based on the theory that any object could be synthesized by breaking it down to multilayers that are needed to be laid at the top of each other to form the final object. Metal- Based additive manufacturing has significant growth in the last couple of years, based on the advantages that AM offers, which is producing complex 3D objects directed from CAD data without the need for that careful and detailed analysis that is needed by the other manufacturing processes. A unique collaboration between architects, façade engineers and manufacturers could be achieved by following a whole new aspect, which is how to move from Design to Production. The merge between design and manufacturing could revolutionize the building process of complex buildings. Moreover, the elimination of several constraints, which usually show up in the planning phases. Additively manufactured parts still need some verification to reach the level that the market and the user can accept and trust., Architectural Engineering +Technology

Architecture, Urbanism and Building Sciences

Rapid developments of both new (digital) fabrication techniques and innovative software facilitate the possibility to design, check and construct objects with great complexity and uniqueness without a large price tag. After new techniques slowly entered the field of architecture, the next step is to apply them in civil engineering to design load-bearing structures, dealing with a large number of load cases, outdoor conditions and strict safety requirements. The application of digital fabrication in civil engineering is examined through a case study: the design of a pedestrian frame bridge made of timber using CNC-milling techniques. In this research a strong focus is on the design, optimisation, detailing and testing of the connections. This research demonstrates that the combination of a reciprocal gridshell structure in combination with interlocking joints (lap joints) is particularly suitable for digital timber fabrication since a stable system can be obtained without the use of fasteners. The uniqueness of all connections and the strong relation between them makes the design process complex. Nevertheless, with the help of digital design tools like Grasshopper and evolutionary it is possible to deal with a large number of parameters with a complex relation between them. Additionally lab tests were carried out to get insight in the shear capacity of notched members. The tests show that the verification method for notched members in Eurocode 5 does not accurately predict the shear strength when hardwood is applied. Additional research on the fracture energy of hardwood is required to propose an improved calculation method. Furthermore, the tests have shown that the application of rounded edges and screws as reinforcement significantly improve the shear capacity of notched members. It is therefore always advised to apply rounded edges, if possible in combination with screws. All in all, the case study has shown that it is poss, Civil Engineering | Structural Engineering

Free-form solar cells are cells of unconventional shapes (e.g. hexagonal, leaf-shaped etc). Their flexible shape adds to the aesthetics of the surroundings as well as allows to place them over objects where conventional solar cells might not fit. Evidently, these cells need to be efficient as well, and one of the important factors that controls their performance is the front metallization design. In this paper, we present the application of topology optimization (TO) to optimize the front metallization patterns for free-form solar cells. TO distributes the electrode material on the solar cell front surface in an efficient manner, such that the total power output is maximized. To demonstrate the capability of the proposed methodology, we use it to optimize front metal grids for several complex solar cell shapes e.g. circular, hexagonal, leaf-shaped, motorbike fairings, etc. The results presented here demonstrate the capability of TO to generate efficient designs for these free-form shapes., Structural Optimization and Mechanics

Free-form solar cells are cells of unconventional shapes (e.g. hexagonal, leaf-shaped etc). Their flexible shape adds to the aesthetics of the surroundings as well as allows to place them over objects where conventional solar cells might not fit. Evidently, these cells need to be efficient as well, and one of the important factors that controls their performance is the front metallization design. In this paper, we present the application of topology optimization (TO) to optimize the front metallization patterns for free-form solar cells. TO distributes the electrode material on the solar cell front surface in an efficient manner, such that the total power output is maximized. To demonstrate the capability of the proposed methodology, we use it to optimize front metal grids for several complex solar cell shapes e.g. circular, hexagonal, leaf-shaped, motorbike fairings, etc. The results presented here demonstrate the capability of TO to generate efficient designs for these free-form shapes., Computational Design and Mechanics

[EN] The design and construction of free-form structures is generally accomplished through the use of either planar triangular facets or curved panels. The construction with quadrilateral and hexagonal possesses a number of important advantages over triangular meshes: they have a smaller number of edges, resulting in a smaller number of supporting beams following the edges, less steel and less cost. Quadrilateral and hexagonal meshes also have a lower node complexity, because at each vertex there are a small number of edges, because vertices have less index. In this master thesis, sorne methods for creating an almost unlimited multitude of shapes for doublecurved surfaces with planar quadrangles are studied. l. First we give a constructive method to build traslation and revolution surfaces with planar quadrilateral meshes, using a limited number of different panels. 2. After that, we study algorithms to build more complex surfaces with planar quadrilateral meshes. All the resulting panels are usually diffrents. Finafly, we study the panelization of free-form surfaces using planar hexagonal meshes. The methods generate planar hexagonal meshes from an initial triangular mesh. We give a method for the panelization of an ellipsoid with planar hexagonal meshes, using the Fekete points as initial mesh. An algorithm to obtain Fekete points in the unit sphere is also studied., [ES] El diseño y construcción de formas libres en la arquitectura se resuelve generalmente mediante la discretización con paneles triangulares, o paneles curvos de un mayor número de lados. La construcción con paneles cuadrangulares o hexagonales presenta importantes ventajas respecto al uso de paneles triangulares: tienen un menor número de aristas, lo que implica un menor cantidad de acero en la estructura portante y por tanto menor coste. Además presentan una menor complejidad de los nodos, debido al menor número de aristas que convergen en cada vértice ya que éstos tienen menor índice. En el presente trabajo se estudian diferentes métodos para la construcción de superficies discretas de doble curvatura con paneles cuadrangulares planos. l. En primer lugar, se dá un método constructivo para la construcción de superficies de traslación y revolución, utilizando un número limitado de paneles diferentes. 2. Después se estudian algoritmos para la construcción de superficies más complejas resueltas con cuadriláteros, en este caso todos los paneles son, en general, diferentes. Por último se estudia la construcción de formas libres con paneles hexagonales planos. Estos métodos generan un mallado hexagonal plano a partir de un mallado triangular inicial. Damos un algoritmo para la discretización de un elipsoide con paneles hexagonales planos, utilizando los puntos de Fekete como mallado inicial. Se estudia también un algoritmo para la distribución de puntos de Fekete sobre la esfera unidad.

[EN] The design and construction of free-form structures is generally accomplished through the use of either planar triangular facets or curved panels. The construction with quadrilateral and hexagonal possesses a number of important advantages over triangular meshes: they have a smaller number of edges, resulting in a smaller number of supporting beams following the edges, less steel and less cost. Quadrilateral and hexagonal meshes also have a lower node complexity, because at each vertex there are a small number of edges, because vertices have less index. In this master thesis, sorne methods for creating an almost unlimited multitude of shapes for doublecurved surfaces with planar quadrangles are studied. l. First we give a constructive method to build traslation and revolution surfaces with planar quadrilateral meshes, using a limited number of different panels. 2. After that, we study algorithms to build more complex surfaces with planar quadrilateral meshes. All the resulting panels are usually diffrents. Finafly, we study the panelization of free-form surfaces using planar hexagonal meshes. The methods generate planar hexagonal meshes from an initial triangular mesh. We give a method for the panelization of an ellipsoid with planar hexagonal meshes, using the Fekete points as initial mesh. An algorithm to obtain Fekete points in the unit sphere is also studied., [ES] El diseño y construcción de formas libres en la arquitectura se resuelve generalmente mediante la discretización con paneles triangulares, o paneles curvos de un mayor número de lados. La construcción con paneles cuadrangulares o hexagonales presenta importantes ventajas respecto al uso de paneles triangulares: tienen un menor número de aristas, lo que implica un menor cantidad de acero en la estructura portante y por tanto menor coste. Además presentan una menor complejidad de los nodos, debido al menor número de aristas que convergen en cada vértice ya que éstos tienen menor índice. En el presente trabajo se estudian diferentes métodos para la construcción de superficies discretas de doble curvatura con paneles cuadrangulares planos. l. En primer lugar, se dá un método constructivo para la construcción de superficies de traslación y revolución, utilizando un número limitado de paneles diferentes. 2. Después se estudian algoritmos para la construcción de superficies más complejas resueltas con cuadriláteros, en este caso todos los paneles son, en general, diferentes. Por último se estudia la construcción de formas libres con paneles hexagonales planos. Estos métodos generan un mallado hexagonal plano a partir de un mallado triangular inicial. Damos un algoritmo para la discretización de un elipsoide con paneles hexagonales planos, utilizando los puntos de Fekete como mallado inicial. Se estudia también un algoritmo para la distribución de puntos de Fekete sobre la esfera unidad.

[EN] The design and construction of free-form structures is generally accomplished through the use of either planar triangular facets or curved panels. The construction with quadrilateral and hexagonal possesses a number of important advantages over triangular meshes: they have a smaller number of edges, resulting in a smaller number of supporting beams following the edges, less steel and less cost. Quadrilateral and hexagonal meshes also have a lower node complexity, because at each vertex there are a small number of edges, because vertices have less index. In this master thesis, sorne methods for creating an almost unlimited multitude of shapes for doublecurved surfaces with planar quadrangles are studied. l. First we give a constructive method to build traslation and revolution surfaces with planar quadrilateral meshes, using a limited number of different panels. 2. After that, we study algorithms to build more complex surfaces with planar quadrilateral meshes. All the resulting panels are usually diffrents. Finafly, we study the panelization of free-form surfaces using planar hexagonal meshes. The methods generate planar hexagonal meshes from an initial triangular mesh. We give a method for the panelization of an ellipsoid with planar hexagonal meshes, using the Fekete points as initial mesh. An algorithm to obtain Fekete points in the unit sphere is also studied., [ES] El diseño y construcción de formas libres en la arquitectura se resuelve generalmente mediante la discretización con paneles triangulares, o paneles curvos de un mayor número de lados. La construcción con paneles cuadrangulares o hexagonales presenta importantes ventajas respecto al uso de paneles triangulares: tienen un menor número de aristas, lo que implica un menor cantidad de acero en la estructura portante y por tanto menor coste. Además presentan una menor complejidad de los nodos, debido al menor número de aristas que convergen en cada vértice ya que éstos tienen menor índice. En el presente trabajo se estudian diferentes métodos para la construcción de superficies discretas de doble curvatura con paneles cuadrangulares planos. l. En primer lugar, se dá un método constructivo para la construcción de superficies de traslación y revolución, utilizando un número limitado de paneles diferentes. 2. Después se estudian algoritmos para la construcción de superficies más complejas resueltas con cuadriláteros, en este caso todos los paneles son, en general, diferentes. Por último se estudia la construcción de formas libres con paneles hexagonales planos. Estos métodos generan un mallado hexagonal plano a partir de un mallado triangular inicial. Damos un algoritmo para la discretización de un elipsoide con paneles hexagonales planos, utilizando los puntos de Fekete como mallado inicial. Se estudia también un algoritmo para la distribución de puntos de Fekete sobre la esfera unidad.

This study is concerned with the development of a method for creating shapes and form in clothing with minimum exertion on the cloth, using simple construction techniques. It is an exploration of an approach to producing clothing in a less familiar manner to the usual way of working which involves, almost always, drafting or flat-pattern making. With the expression of the movement of the textile around the body as the main aim, the ‘push/pull’ principle is employed to direct its flow in both a symmetric and asymmetric fashion. It is a principle inspired by Madame Gres, the French designer of the 1930s to 1980s, famous for her neo-classic inspired gowns. The textile, usually a rectangle, is manipulated without cutting into it but by pushing and pulling first, through the upper limbs of the body, and then ‘worked’ around the rest of the body, using draping and pleating to create shapes which are spontaneous, elaborate and not pre-determined. Furthermore, the approach explores the aesthetic potential of draping and combining the Filter 80 PPI, an industrial textile used for filtering, with conventional clothing materials, linen and/or cotton in this case. The parallels and constasts of this mix are noted, together with the distinct expressions, which nonetheless both display a simple approach in construction, minimal manipulation of the textile, the use of the upper limbs as natural obstacles, and the ‘no-cut’ principle of the rectangular piece of cloth. With free form construction and reflection, one discovers expressions possible only through the use of an experimental approach in working., Program: Master Programme in Fashion and Textile Design

This study is concerned with the development of a method for creating shapes and form in clothing with minimum exertion on the cloth, using simple construction techniques. It is an exploration of an approach to producing clothing in a less familiar manner to the usual way of working which involves, almost always, drafting or flat-pattern making. With the expression of the movement of the textile around the body as the main aim, the ‘push/pull’ principle is employed to direct its flow in both a symmetric and asymmetric fashion. It is a principle inspired by Madame Gres, the French designer of the 1930s to 1980s, famous for her neo-classic inspired gowns. The textile, usually a rectangle, is manipulated without cutting into it but by pushing and pulling first, through the upper limbs of the body, and then ‘worked’ around the rest of the body, using draping and pleating to create shapes which are spontaneous, elaborate and not pre-determined. Furthermore, the approach explores the aesthetic potential of draping and combining the Filter 80 PPI, an industrial textile used for filtering, with conventional clothing materials, linen and/or cotton in this case. The parallels and constasts of this mix are noted, together with the distinct expressions, which nonetheless both display a simple approach in construction, minimal manipulation of the textile, the use of the upper limbs as natural obstacles, and the ‘no-cut’ principle of the rectangular piece of cloth. With free form construction and reflection, one discovers expressions possible only through the use of an experimental approach in working., Program: Master Programme in Fashion and Textile Design

The project ‘‘Brick-topia’’ was based on a combination of the latest structural analysis and form-finding computational tools with traditional, cheap and effective construction techniques. It is the result of innovation to fight against budget and time. The initial budget was 3000 euros and only seven weeks was the time to look for sponsors, design the pavilion, plan the construction phases and build it. The whole process of designing, decision on the materials, structural analysis and construction is presented in the paper, including exploration on new form-finding methods to redesign a project in situ and research on a new formwork system using scaffolding, cardboard, wire and steel rods and having a cutter as main tool, Postprint (published version)

In an earlier article (CPI issue of August 2011 [1]) a method was presented for producing precast curved panels with a thickness of a few centimeters using the 'flexible mould method'. This method is the central theme in the PhD study of the first author on the realization of freeform architecture in concrete. The concrete panels manufactured with the flexible mould method can be applied for many architectural purposes in which curvature is present, such as facade cladding, precast plank floors or roof elements. The method essentially comprises a reusable and bendable smooth surface that can be deformed into a wide range of geometries, including variable curvatures in one or two directions and freely shaped edge contours. In the earlier article in CPI it was concluded that some aspects needed further research, among which were the choice of suitable concrete mixtures and the investigation of fibre reinforcement. This article discusses the results of experiments investigating these aspects: the mixture choice was guided by measuring the workability in time and the ability to undergo deformations after casting without cracking. Furthermore, AR-glass textile was used to strengthen the panels with a flexible reinforcement that allowed deformation in the non-hardened state. Experimental work has been done to check the position of the reinforcement after deformation and the contribution of the textiles to the strength of the panels., Structural Engineering, Civil Engineering and Geosciences

In an earlier article (CPI issue of August 2011 [1]) a method was presented for producing precast curved panels with a thickness of a few centimeters using the 'flexible mould method'. This method is the central theme in the PhD study of the first author on the realization of freeform architecture in concrete. The concrete panels manufactured with the flexible mould method can be applied for many architectural purposes in which curvature is present, such as facade cladding, precast plank floors or roof elements. The method essentially comprises a reusable and bendable smooth surface that can be deformed into a wide range of geometries, including variable curvatures in one or two directions and freely shaped edge contours. In the earlier article in CPI it was concluded that some aspects needed further research, among which were the choice of suitable concrete mixtures and the investigation of fibre reinforcement. This article discusses the results of experiments investigating these aspects: the mixture choice was guided by measuring the workability in time and the ability to undergo deformations after casting without cracking. Furthermore, AR-glass textile was used to strengthen the panels with a flexible reinforcement that allowed deformation in the non-hardened state. Experimental work has been done to check the position of the reinforcement after deformation and the contribution of the textiles to the strength of the panels., Structural Engineering, Civil Engineering and Geosciences

The paper reviews possibilities of application of structural performance-based methods for production of geometrically complex, non-conventional architectural forms. Starting from the fact that advanced digital technologies and multidisciplinary approach have significantly changed traditional relations in design process, this work indicates at potentials of application of methods, procedures and tools initially not designed for architectural production. Based on biological paradigm, morphogenetic strategies in the field of architecture represent dynamic operation-based form-finding methods. The focus of the paper will be on conceptualization of morphogenetic procedure for production of integrated morphologic solutions which are characterized by optimal form-structure interdependence. The procedure is based on isogeometric concept, which enables integration of CAD and FEA. Compared to the conventional FEA, in which geometric interpolation is carried, the isogeometry analysis is based on exactly defined initial geometry, thus enabling design, analysis and refinement of models by using a single data type, which considerably facilitates and accelerates the process of repeated analysis of variant forms. The objective of this paper is to confirm the thesis that transposition, advancement and integration of creative tools affect reconsideration of conventional approaches, methods and procedures, thus enabling innovation and optimization of the design process., Radom se razmatra mogućnost upotrebe metoda zasnovanih na strukturalnim performansama u produkciji geometrijski kompleksnih nekonvencionalnih arhitektonskih formi. Polazeći od činjenice da su napredne digitalne tehnologije i multidisciplinarni pristup u značajnoj meri izmenili tradicionalne relacije procesa projektovanja, ukazuje se na potencijale korišćenja metoda, procesa i alata koji inicijalno nisu namenjeni arhitektonskoj produkciji. Bazirane na biološkoj paradigmi, morfogenetske strategije u oblasti arhitekture predstavljaju dinamične operaciono-zasnovane metode za pronalaženje forme (form-finding). Težište rada biće na koncipiranju morfogenetske procedure za dizajn integrisanih morfoloških rešenja koje karakteriše optimalna međuzavisnost forma-struktura. Procedura se zasniva na korišćenju izogeometrijskog koncepta, kojim je omogućena integracija CAD i FEA. Za razliku od klasične FEA, u kojoj se vrši interpolacija geometrije, u izogeometriji analiza se vrši na osnovu egzaktno definisane početne geometrije, čime je omogućen dizajn, analiza i podešavanje modela upotrebom jedinstvenog tipa podataka, a što značajno olakšava i ubrzava proces uzastopnih analiza varijantnih formi. Rad je u funkciji potvrđivanja teze da transpozicija, unapređenje i integracija kreativnih alata utiču na preispitivanje konvencionalnih pristupa, metoda i procedura omogućavajući inovaciju i optimizaciju samog procesa projektovanja.

Due to the complexity of the freeform shapes it is often not possible to distinguish any repetitive elements in freeform buildings at all. Most freeform building designs consist of many single or double curved surfaces which require complex shapes for the mould and element edges. Since the costs of the moulds (formwork) for precast concrete make up a significant percentage of the final price per element or per square meter, the feasibility of freeform buildings in precast concrete is still far from optimal. The PhD research carried out at Delft University of Technology, Faculty ofCivil Engineering, aims to improve the applicability of precast concrete through the development of a flexible mould. At the end of the research the design specifications of vital parts of the flexible mould should be described, and supported by theoretical and experimental study as a proof of concept., Structural Engineering, Civil Engineering and Geosciences

p. 1367-1378, Recently the MyZeil shopping mall as a part of the PalaisQuartier has been opened to the public in the very center of Frankfurt in Germany. It consists of two high-rises including one office tower, one hotel tower and a five-storey retail building. The core part is the MyZeil with around 78.000m² gross storey area designed by the Italian architect Massimiliano Fuksas. The building agglomeration is covered by a 13500m² triangulated glass/steel roof and rhombus shaped facades. The following article will highlight the special approach and procedures which have been applied during design, fabrication and installation of the roof and for its maintenance. First the overall geometry was optimized by close coordination with the architect in order to fulfil the aesthetic as well as the structural requirements. At this stage Rhino-files were used to communicate the numerous alternatives of the roof geometry between the architect and the engineer. Much effort was put into the meshing of the grid on the heavily curved 3D surface. Special tools, had to be developed to produce a net according to the flow of forces. In the next step the nodal connectors had to be designed in a way that they could be adjusted to all geometries and to all loading conditions. For the structural analysis of the members and nodes of the grid the same geometric data model was used that served as a basis for the shop drawings and the fabrication of the hollow box steel members and its nodal connectors. The structure was then erected by welding the members on site which allowed to meet the specified tolerances. At the end, a highly optimized structure was achieved which not only marks the state of the art for grid shells but which is also an architectural landmark in the city of Frankfurt.

Due to the complexity of the freeform shapes it is often not possible to distinguish any repetitive elements in freeform buildings at all. Most freeform building designs consist of many single or double curved surfaces which require complex shapes for the mould and element edges. Since the costs of the moulds (formwork) for precast concrete make up a significant percentage of the final price per element or per square meter, the feasibility of freeform buildings in precast concrete is still far from optimal. The PhD research carried out at Delft University of Technology, Faculty ofCivil Engineering, aims to improve the applicability of precast concrete through the development of a flexible mould. At the end of the research the design specifications of vital parts of the flexible mould should be described, and supported by theoretical and experimental study as a proof of concept., Structural Engineering, Civil Engineering and Geosciences

p. 1263-1274, Zaha Hadid Architects designed a complex free-form envelope to house the new Heydar Aliyev Cultural Centre in Baku, Azerbaijan. The cultural centre comprises a library, an auditorium and a museum together with other complementary facilities. The architectural space envelope is double layered, that is, it consists of an external and an internal skin with a variable distance in between. A special requirement for the appearance of the cladding panels is the paths of their intermediate joints, which visibly run parallel in one direction, thus accentuating the smoothness of the surface and suggesting a natural flow. The present paper discusses and illustrates how visual, architectural and constructional requirements posed very demanding conditions for designing and modelling the MERO-TSK space structure, which is the actual structural system not only supporting the space envelopes, but a convenient form-giving construction basis to materialise their cladding surfaces.

p. 1367-1378, Recently the MyZeil shopping mall as a part of the PalaisQuartier has been opened to the public in the very center of Frankfurt in Germany. It consists of two high-rises including one office tower, one hotel tower and a five-storey retail building. The core part is the MyZeil with around 78.000m² gross storey area designed by the Italian architect Massimiliano Fuksas. The building agglomeration is covered by a 13500m² triangulated glass/steel roof and rhombus shaped facades. The following article will highlight the special approach and procedures which have been applied during design, fabrication and installation of the roof and for its maintenance. First the overall geometry was optimized by close coordination with the architect in order to fulfil the aesthetic as well as the structural requirements. At this stage Rhino-files were used to communicate the numerous alternatives of the roof geometry between the architect and the engineer. Much effort was put into the meshing of the grid on the heavily curved 3D surface. Special tools, had to be developed to produce a net according to the flow of forces. In the next step the nodal connectors had to be designed in a way that they could be adjusted to all geometries and to all loading conditions. For the structural analysis of the members and nodes of the grid the same geometric data model was used that served as a basis for the shop drawings and the fabrication of the hollow box steel members and its nodal connectors. The structure was then erected by welding the members on site which allowed to meet the specified tolerances. At the end, a highly optimized structure was achieved which not only marks the state of the art for grid shells but which is also an architectural landmark in the city of Frankfurt.

p. 966-876, The new geometrical developments open new perspectives for free-form design, making it possible to escape from planar triangular or quadrilateral discretizations. Recent advances in theory algorithms allow for the discretization of any surface using only single curvature panels thus allowing the realisation of smooth double curvature glazed envelops of any form. Grid shell structures usually present a nearly in plane uniform behaviour, but previous realisations have shown that grid shells can be designed also according to an anisotropic inplane arrangement. The control of principal direction and the fine tuning of the stiffness of the different structural elements (arcs, cables etc.) is a tool for adjusting the form-finding thus controlling the resulting geometry. Moreover, the form-finding can also be performed without researching a constant stress (self weight); in this case an even wider range of forms become possible. These new geometrical and structural approaches have been coupled together and tested in re-designing, as a case study, the glazed roof of the Neumunster Abbey in Luxembourg. Such approach allowed for the conception of an efficient structure supporting a smooth double curvature glass skin, made out of only single curvature panels, perfectly coherent with the perimeter of the courtyard i.e. matching all the edges without any gaps.

p. 966-876, The new geometrical developments open new perspectives for free-form design, making it possible to escape from planar triangular or quadrilateral discretizations. Recent advances in theory algorithms allow for the discretization of any surface using only single curvature panels thus allowing the realisation of smooth double curvature glazed envelops of any form. Grid shell structures usually present a nearly in plane uniform behaviour, but previous realisations have shown that grid shells can be designed also according to an anisotropic inplane arrangement. The control of principal direction and the fine tuning of the stiffness of the different structural elements (arcs, cables etc.) is a tool for adjusting the form-finding thus controlling the resulting geometry. Moreover, the form-finding can also be performed without researching a constant stress (self weight); in this case an even wider range of forms become possible. These new geometrical and structural approaches have been coupled together and tested in re-designing, as a case study, the glazed roof of the Neumunster Abbey in Luxembourg. Such approach allowed for the conception of an efficient structure supporting a smooth double curvature glass skin, made out of only single curvature panels, perfectly coherent with the perimeter of the courtyard i.e. matching all the edges without any gaps.

p. 1367-1378, Recently the MyZeil shopping mall as a part of the PalaisQuartier has been opened to the public in the very center of Frankfurt in Germany. It consists of two high-rises including one office tower, one hotel tower and a five-storey retail building. The core part is the MyZeil with around 78.000m² gross storey area designed by the Italian architect Massimiliano Fuksas. The building agglomeration is covered by a 13500m² triangulated glass/steel roof and rhombus shaped facades. The following article will highlight the special approach and procedures which have been applied during design, fabrication and installation of the roof and for its maintenance. First the overall geometry was optimized by close coordination with the architect in order to fulfil the aesthetic as well as the structural requirements. At this stage Rhino-files were used to communicate the numerous alternatives of the roof geometry between the architect and the engineer. Much effort was put into the meshing of the grid on the heavily curved 3D surface. Special tools, had to be developed to produce a net according to the flow of forces. In the next step the nodal connectors had to be designed in a way that they could be adjusted to all geometries and to all loading conditions. For the structural analysis of the members and nodes of the grid the same geometric data model was used that served as a basis for the shop drawings and the fabrication of the hollow box steel members and its nodal connectors. The structure was then erected by welding the members on site which allowed to meet the specified tolerances. At the end, a highly optimized structure was achieved which not only marks the state of the art for grid shells but which is also an architectural landmark in the city of Frankfurt.

p. 977-988, For free-forms the structural grid affects the design of the envelope as well as the design of the structure. Due to the complex geometry of the surface the directions of the normal lines will vary. The diversity of the directions of the normal lines affects the design of the envelope and structure, especially in case the surface is connected directly, without secondary structure, to the members of the structural frame and the structural members have to be curved and twisted. Comparing several structural grids shows the effect of the grid for the directions of the normal lines and the design of the structural elements.

p. 1263-1274, Zaha Hadid Architects designed a complex free-form envelope to house the new Heydar Aliyev Cultural Centre in Baku, Azerbaijan. The cultural centre comprises a library, an auditorium and a museum together with other complementary facilities. The architectural space envelope is double layered, that is, it consists of an external and an internal skin with a variable distance in between. A special requirement for the appearance of the cladding panels is the paths of their intermediate joints, which visibly run parallel in one direction, thus accentuating the smoothness of the surface and suggesting a natural flow. The present paper discusses and illustrates how visual, architectural and constructional requirements posed very demanding conditions for designing and modelling the MERO-TSK space structure, which is the actual structural system not only supporting the space envelopes, but a convenient form-giving construction basis to materialise their cladding surfaces.

p. 966-876, The new geometrical developments open new perspectives for free-form design, making it possible to escape from planar triangular or quadrilateral discretizations. Recent advances in theory algorithms allow for the discretization of any surface using only single curvature panels thus allowing the realisation of smooth double curvature glazed envelops of any form. Grid shell structures usually present a nearly in plane uniform behaviour, but previous realisations have shown that grid shells can be designed also according to an anisotropic inplane arrangement. The control of principal direction and the fine tuning of the stiffness of the different structural elements (arcs, cables etc.) is a tool for adjusting the form-finding thus controlling the resulting geometry. Moreover, the form-finding can also be performed without researching a constant stress (self weight); in this case an even wider range of forms become possible. These new geometrical and structural approaches have been coupled together and tested in re-designing, as a case study, the glazed roof of the Neumunster Abbey in Luxembourg. Such approach allowed for the conception of an efficient structure supporting a smooth double curvature glass skin, made out of only single curvature panels, perfectly coherent with the perimeter of the courtyard i.e. matching all the edges without any gaps.

p. 977-988, For free-forms the structural grid affects the design of the envelope as well as the design of the structure. Due to the complex geometry of the surface the directions of the normal lines will vary. The diversity of the directions of the normal lines affects the design of the envelope and structure, especially in case the surface is connected directly, without secondary structure, to the members of the structural frame and the structural members have to be curved and twisted. Comparing several structural grids shows the effect of the grid for the directions of the normal lines and the design of the structural elements.

p. 1263-1274, Zaha Hadid Architects designed a complex free-form envelope to house the new Heydar Aliyev Cultural Centre in Baku, Azerbaijan. The cultural centre comprises a library, an auditorium and a museum together with other complementary facilities. The architectural space envelope is double layered, that is, it consists of an external and an internal skin with a variable distance in between. A special requirement for the appearance of the cladding panels is the paths of their intermediate joints, which visibly run parallel in one direction, thus accentuating the smoothness of the surface and suggesting a natural flow. The present paper discusses and illustrates how visual, architectural and constructional requirements posed very demanding conditions for designing and modelling the MERO-TSK space structure, which is the actual structural system not only supporting the space envelopes, but a convenient form-giving construction basis to materialise their cladding surfaces.

p. 1032-1043, For free-forms as well as shells the choice of the grid of the structural system will be decisive for the architectural and structural design. This paper analysis several grids concerning the load transfer and construction. To generalize this analysis, the surface of the free-form is designed by stretching a half sphere, so the ground plan is an ellipse.

p. 1032-1043, For free-forms as well as shells the choice of the grid of the structural system will be decisive for the architectural and structural design. This paper analysis several grids concerning the load transfer and construction. To generalize this analysis, the surface of the free-form is designed by stretching a half sphere, so the ground plan is an ellipse.

p. 1032-1043, For free-forms as well as shells the choice of the grid of the structural system will be decisive for the architectural and structural design. This paper analysis several grids concerning the load transfer and construction. To generalize this analysis, the surface of the free-form is designed by stretching a half sphere, so the ground plan is an ellipse.

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Architecture