ROBOTIC FORCE PRINTING

Philip F. Yuan Philippe Block

A JOINT WORKSHOP OF MIT/ETH/TONGJI

TONGJI UNIVERSITY PRESS

CONTENTS

INTRODUCTION FORM FOLLOWS ROBOTIC FORCE PRINTING

8

Philip F. Yuan

PREFACE DIGITAL MASTER BUILDERS: EXPLORING STRENGTH THROUGH GEOMETRY

22

Philippe Block

PRECEDENTS FORM, FORCE AND FABRICATION

32

Gene Ting-Chun Kao Kam-Ming Mark Tam

BENDING-ACTIVE FORMWORK FOR SHELL STRUCTURES BASED ON 3D-PRINTING TECHNOLOGY

44

Xiang Wang

PROGRAMMING OF ROBOTIC FABRICATION Liming Zhang

METHODOLOGY

54

CONTENTS

INTRODUCTION FORM FOLLOWS ROBOTIC FORCE PRINTING

8

Philip F. Yuan

PREFACE DIGITAL MASTER BUILDERS: EXPLORING STRENGTH THROUGH GEOMETRY

22

Philippe Block

PRECEDENTS FORM, FORCE AND FABRICATION

32

Gene Ting-Chun Kao Kam-Ming Mark Tam

BENDING-ACTIVE FORMWORK FOR SHELL STRUCTURES BASED ON 3D-PRINTING TECHNOLOGY

44

Xiang Wang

PROGRAMMING OF ROBOTIC FABRICATION Liming Zhang

METHODOLOGY

54

PREFACE

PRELIMINARY GROUP WORKS SNAKE ROCK PAVILION

74

SHELL O

82

FRACTAL SHELL

90

FOLDED BRIDGE

98

EIGHT-LEGGED SHELL

106

WHITE HILL

114

THE RIBBON

122

FINAL FABRICATION WORKS BENDING SHELL PAVILION

130

FU BRIDGE

154

5

PREFACE

PRELIMINARY GROUP WORKS SNAKE ROCK PAVILION

74

SHELL O

82

FRACTAL SHELL

90

FOLDED BRIDGE

98

EIGHT-LEGGED SHELL

106

WHITE HILL

114

THE RIBBON

122

FINAL FABRICATION WORKS BENDING SHELL PAVILION

130

FU BRIDGE

154

5

ROBOTIC FORCE PRINTING

INTRODUCTION

INTRODUCTION

6

7

ROBOTIC FORCE PRINTING

INTRODUCTION

INTRODUCTION

6

7

ROBOTIC FORCE PRINTING the proper double curved geometry. Normally, large scaffoldings are used to control the form and take the load of the partial shell structure before it completes its shape (Figure 2). Therefore, it is this reason that makes the building of a shell structure not as efficient as it appears to be with its geometry and structural behavior. To solve this problem, architects and researchers have developed concepts with the smart usage of different geometry and materials. Felix Candela developed the way to only use a ruled surface and build with a linear mold system.

Heinz Isler suggested the pneumatic formwork system and enabled a quick building process with removable, lightweight flexible material. Frei Otto applied the degree of freedom of a quadrilateral grid system to develop the gridshell structure concept.

Nowadays, 3D-printing technology provides the building industry with a lot of possibilities. In this research, 3D-printed sheets with structural patterns are supposed to be used as the support of the shell structure, to enable a feasible and efficient building method.

Bending-Active Structure and the Geometry of Bending Julian Lienhard proposed a potential structural typology which uses its curvature with the form to improve the stiffness of the structure [8]. With suitable materials such as the FRP, which can offer enough strength at the same time with sufficient bending, it is possible to utilize the curved bending geometry to stabilize the structure with flexible materials (such structural behavior can be easily explained by the stiffening effect to use creases and bending for a sheet of paper as shown in Figure 3). o combine the basic requirement of the deliberately designed geometry based on a form-finding process with geometrical restrictions of the active-bending form, it is the first basic object of this pre-research to define the principles of the geometry. Experienced from a relevant research based on the curved-crease-folding and shell with thin sheets, a Y-shape prototype is used to define the total structure and also used in predominant form-finding. Based on a primary compression-only structural form designed with RhinoVAULT, spatial curves can be achieved from each leg of the Y-branch. By developing a quasi-developable surface by simply divide the adjacent curves into large amount

46

PRECEDENTS

Figure 2 Scaffolding system as formwork for the building of concrete shell structures

Figure 3 Top: Stiffening effect of folding with creases with a paper sheet[9], Bottom: the stiffening effect of bending (in single curve and a pseudo-doublecurve) to a paper sheet[10]

47

ROBOTIC FORCE PRINTING the proper double curved geometry. Normally, large scaffoldings are used to control the form and take the load of the partial shell structure before it completes its shape (Figure 2). Therefore, it is this reason that makes the building of a shell structure not as efficient as it appears to be with its geometry and structural behavior. To solve this problem, architects and researchers have developed concepts with the smart usage of different geometry and materials. Felix Candela developed the way to only use a ruled surface and build with a linear mold system.

Heinz Isler suggested the pneumatic formwork system and enabled a quick building process with removable, lightweight flexible material. Frei Otto applied the degree of freedom of a quadrilateral grid system to develop the gridshell structure concept.

Nowadays, 3D-printing technology provides the building industry with a lot of possibilities. In this research, 3D-printed sheets with structural patterns are supposed to be used as the support of the shell structure, to enable a feasible and efficient building method.

Bending-Active Structure and the Geometry of Bending Julian Lienhard proposed a potential structural typology which uses its curvature with the form to improve the stiffness of the structure [8]. With suitable materials such as the FRP, which can offer enough strength at the same time with sufficient bending, it is possible to utilize the curved bending geometry to stabilize the structure with flexible materials (such structural behavior can be easily explained by the stiffening effect to use creases and bending for a sheet of paper as shown in Figure 3). o combine the basic requirement of the deliberately designed geometry based on a form-finding process with geometrical restrictions of the active-bending form, it is the first basic object of this pre-research to define the principles of the geometry. Experienced from a relevant research based on the curved-crease-folding and shell with thin sheets, a Y-shape prototype is used to define the total structure and also used in predominant form-finding. Based on a primary compression-only structural form designed with RhinoVAULT, spatial curves can be achieved from each leg of the Y-branch. By developing a quasi-developable surface by simply divide the adjacent curves into large amount

46

PRECEDENTS

Figure 2 Scaffolding system as formwork for the building of concrete shell structures

Figure 3 Top: Stiffening effect of folding with creases with a paper sheet[9], Bottom: the stiffening effect of bending (in single curve and a pseudo-doublecurve) to a paper sheet[10]

47

ROBOTIC FORCE PRINTING Figure 4

PRECEDENTS elements and connecting points to compose plenty of triangles, it is able to unroll the polysurface into a planar contour. By either laser-cutting the sheet material or 3D printing an arbitrary pattern inside the contour, it is able to bend the structure back to make a spatial shell surface that closely resembles the original design (Figure 4).

It is obvious in the experience that the final form may have a deviation to the ideal one which is derived by the optimization for the developable surface, because the final forming process relies on the bending behavior of the material and the moving of the supports to the target position. For this problem, simulation and analysis of the active-bent form are made to work as an integral part of the workflow.

The simulation of the bending-active geometry can generally be achieved either in a static way to analyze the postbuckling behavior or in a kinetic way to simulate the quasistatic problem. For a quick design feedback of the bent geometry, a simple kinetic analysis method is made with the Kangaroo plug-in in Grasshopper environment. Based on the Particle-Spring-Method, springs are generated with the original unrolled geometry as an input mesh. The target actuation of the system (the movement of the supports) is defined as the large forces added to specific lines. The whole system load is gradually added to slow down the actuation process to avoid a sudden large deformation in the structural system and hence generate a quasi-static result for the bent geometry (Figure 5).

At the same time, similar simulations and analyzing workflows have been tested and achieved with the Finite-ElementAnalysis (FEA) software. In this research, software ABAQUS is used with its Python Interface to export the complicated boundary conditions directly from the Rhinoceros working environment. Different steps (Static-RIKS, Dynamic-Explicit) are tested based on different assumptions of the problem (imagine that as a static problem with a large deformation or a quasi-static problem based on the long-time-span kinetic problem). With the FE analysis, not only the final geometry but also the internal stresses caused by the bending can be analyzed and visualized in the result (Figure 6).

A relevant design experiment with the Y-shape prototype and bending form based on the curvedcrease-folding

Figure 5 Bending simulation of a planar strip based on different boundary conditions and actuation in different steps (simulated with GH plugin Kangaroo)

48

49

ROBOTIC FORCE PRINTING Figure 4

PRECEDENTS elements and connecting points to compose plenty of triangles, it is able to unroll the polysurface into a planar contour. By either laser-cutting the sheet material or 3D printing an arbitrary pattern inside the contour, it is able to bend the structure back to make a spatial shell surface that closely resembles the original design (Figure 4).

It is obvious in the experience that the final form may have a deviation to the ideal one which is derived by the optimization for the developable surface, because the final forming process relies on the bending behavior of the material and the moving of the supports to the target position. For this problem, simulation and analysis of the active-bent form are made to work as an integral part of the workflow.

The simulation of the bending-active geometry can generally be achieved either in a static way to analyze the postbuckling behavior or in a kinetic way to simulate the quasistatic problem. For a quick design feedback of the bent geometry, a simple kinetic analysis method is made with the Kangaroo plug-in in Grasshopper environment. Based on the Particle-Spring-Method, springs are generated with the original unrolled geometry as an input mesh. The target actuation of the system (the movement of the supports) is defined as the large forces added to specific lines. The whole system load is gradually added to slow down the actuation process to avoid a sudden large deformation in the structural system and hence generate a quasi-static result for the bent geometry (Figure 5).

At the same time, similar simulations and analyzing workflows have been tested and achieved with the Finite-ElementAnalysis (FEA) software. In this research, software ABAQUS is used with its Python Interface to export the complicated boundary conditions directly from the Rhinoceros working environment. Different steps (Static-RIKS, Dynamic-Explicit) are tested based on different assumptions of the problem (imagine that as a static problem with a large deformation or a quasi-static problem based on the long-time-span kinetic problem). With the FE analysis, not only the final geometry but also the internal stresses caused by the bending can be analyzed and visualized in the result (Figure 6).

A relevant design experiment with the Y-shape prototype and bending form based on the curvedcrease-folding

Figure 5 Bending simulation of a planar strip based on different boundary conditions and actuation in different steps (simulated with GH plugin Kangaroo)

48

49

ROBOTIC FORCE PRINTING “Printing the Forces”—A Prototypical Pavilion With the aforementioned methodologies and design tools generated for the active-bending shell formwork, a prototypical pavilion is made to testify the feasibility and restrictions of this design method as well as the fabrication technique.

The initial design started from a triangular planar design domain and the form-finding process is made with RhinoVAULT, to find a suitable compression-only form for the shell structure. To make the double-curved 3D printable, the optimization method is initially made with the division of the shell surface into numbers of strips and then bent and connected with glues to get the desired geometry (Figure 7). To enhance the structural behavior of the shell, principal stress lines are also generated and post-processed to be printed as the structural pattern of the shell.

To achieve simple bending and reduce the welding procedure as well as the tolerance it will bring, a simple optimization quasi-loft method is used in the second test to directly get the unrolled shape of the bent shell. The bending process is then analyzed and tested with a 1:10 model to measure deviations. Construction details as well as the building sequence are tested to cast concrete on the formwork and the feasibility is testified with a small scale-model (Figure 8).

As the first demonstrator of the structure concept as well as the building technique, a full-scale prototype is then 3D-printed and building according to the bending simulation (Figure 9). Three layers of Modified PLA are printed with a combination of a UV-grid and the principal stress line grid with an average width gap of about 5 cm.

The forming process is actuated by the tensioning process of some strips to move the boundaries inwards to reach the target point. Finally, the structure shows its robust stiffness with its super thin cross-section and its light weight of roughly 20 kg.

To show the feasibility of the building technique in a complicated design case of a shell structure, a more complex form is designed with the same methodology.

The intercrossed geometry is then optimized into a combination of series of lofted-developable surfaces. To improve the building process, several side trusses are

50

PRECEDENTS Figure 6 Bending simulation of different types of activebending geometries in ABAQUS based on the DynamicExplicit Method to solve a quasistatic problem

Figure 7 Initial design test with the methodology with a simple triangular shell structure and printed in scale 1:20

Figure 8 Refinement of the developable surface and the casting test

51

ROBOTIC FORCE PRINTING “Printing the Forces”—A Prototypical Pavilion With the aforementioned methodologies and design tools generated for the active-bending shell formwork, a prototypical pavilion is made to testify the feasibility and restrictions of this design method as well as the fabrication technique.

The initial design started from a triangular planar design domain and the form-finding process is made with RhinoVAULT, to find a suitable compression-only form for the shell structure. To make the double-curved 3D printable, the optimization method is initially made with the division of the shell surface into numbers of strips and then bent and connected with glues to get the desired geometry (Figure 7). To enhance the structural behavior of the shell, principal stress lines are also generated and post-processed to be printed as the structural pattern of the shell.

To achieve simple bending and reduce the welding procedure as well as the tolerance it will bring, a simple optimization quasi-loft method is used in the second test to directly get the unrolled shape of the bent shell. The bending process is then analyzed and tested with a 1:10 model to measure deviations. Construction details as well as the building sequence are tested to cast concrete on the formwork and the feasibility is testified with a small scale-model (Figure 8).

As the first demonstrator of the structure concept as well as the building technique, a full-scale prototype is then 3D-printed and building according to the bending simulation (Figure 9). Three layers of Modified PLA are printed with a combination of a UV-grid and the principal stress line grid with an average width gap of about 5 cm.

The forming process is actuated by the tensioning process of some strips to move the boundaries inwards to reach the target point. Finally, the structure shows its robust stiffness with its super thin cross-section and its light weight of roughly 20 kg.

To show the feasibility of the building technique in a complicated design case of a shell structure, a more complex form is designed with the same methodology.

The intercrossed geometry is then optimized into a combination of series of lofted-developable surfaces. To improve the building process, several side trusses are

50

PRECEDENTS Figure 6 Bending simulation of different types of activebending geometries in ABAQUS based on the DynamicExplicit Method to solve a quasistatic problem

Figure 7 Initial design test with the methodology with a simple triangular shell structure and printed in scale 1:20

Figure 8 Refinement of the developable surface and the casting test

51

ROBOTIC FORCE PRINTING added to support the structure and help the positioning of the shell surface. With such guides, the assembly of the 3D-printed formwork can be easily assembled to reach the geometry and make it as a purely geometric problem.

In the final building process, 10 mm Glass-Fiber-ReinforcedConcrete (GRC) is casted on-site on the formwork with only supports on the curved edges to test the load-bearing capacity. Finally, the 80 kg 3d-printed formwork took the 400 kg dead load successfully (Figure 10).

Conclusion With pre-research and full-scale pavilion, the efficiency and feasibility of the 3D-printed bending-active shell structure formwork are tested and demonstrated. The workflow is established and improved to enable designers and architects to combine structural considerations and geometrical requirements together in the first step of the design.

More research and tests will be done in the workshop to find more potential improvements and possibilities of the structural concept and the fabrication technique. More analysis of the detailed structural behavior and the formfinding simulation should be further developed. The success of the two designs and pavilions in the workshop will further show the advantages and efficiency of this novel structure concept.

PRECEDENTS Figure 9 Bending process of the prototype printed in full-scale

Figure 10 Final assembly and concrete casting on the active-bent formwork

REFERENCES [6] Otto, F., et al. IL 10 Gitterschalen–Gridshells.

Stuttgart: Institut für leichte Flächentragwerke, 1974.

[1] Méndez Echenagucia, T., D. Pigram, A. Liew, T. Van Mele, and P. Block. Full-Scale Prototype of A CableNet and Fabric Formed Concrete Thin-Shell Roof. Paper presented at the 2018 IASS Symposium, 2018.

[7] Chilton, John, and Heinz Isler. Heinz Isler. London: Thomas Telford, 2000.

[2] Flügge, W. Stresses in Shells. Berlin: Springer Verlag, 1973.

[8] Lienhard, Julian, and Jan Knippers. “Bending-Active Structures. Form-Finding Strategies Using Elastic Deformation in Static and Kenetic Systems and the Structural Potentials Therein.” ITKE, Stuttgart, 2014.

[3] Adriaenssens, S., P. Block, D. Veenendaal, and C. Williams, Shell Structures for Architecture: Form Finding and Optimization, London: Routledge, 2014.

[4] Piker, D. “Kangaroo: Form Finding with Computational Physics.” Architectural Design 83, no. 2 (2013): 136-137.

[9] Siegel, C., Strukturformen der modernen Architektur: München: Callwey Verlag, 1960.

[5] Rippmann, M., L. Lachauer., and P. Block, “RhinoVAULT—Designing Funicular Form with Rhino”, computer software, 2012.

[10] Pini, V., J. Ruz, P. Kosaka, O. Malvar, M. Calleja, and J. Tamayo, “How Two-Dimensional Bending can Extraordinarily Stiffen Thin Sheets. ” Scientific Reports 6, Article number: 29627, 2016.

52

53

ROBOTIC FORCE PRINTING added to support the structure and help the positioning of the shell surface. With such guides, the assembly of the 3D-printed formwork can be easily assembled to reach the geometry and make it as a purely geometric problem.

In the final building process, 10 mm Glass-Fiber-ReinforcedConcrete (GRC) is casted on-site on the formwork with only supports on the curved edges to test the load-bearing capacity. Finally, the 80 kg 3d-printed formwork took the 400 kg dead load successfully (Figure 10).

Conclusion With pre-research and full-scale pavilion, the efficiency and feasibility of the 3D-printed bending-active shell structure formwork are tested and demonstrated. The workflow is established and improved to enable designers and architects to combine structural considerations and geometrical requirements together in the first step of the design.

More research and tests will be done in the workshop to find more potential improvements and possibilities of the structural concept and the fabrication technique. More analysis of the detailed structural behavior and the formfinding simulation should be further developed. The success of the two designs and pavilions in the workshop will further show the advantages and efficiency of this novel structure concept.

PRECEDENTS Figure 9 Bending process of the prototype printed in full-scale

Figure 10 Final assembly and concrete casting on the active-bent formwork

REFERENCES [6] Otto, F., et al. IL 10 Gitterschalen–Gridshells.

Stuttgart: Institut für leichte Flächentragwerke, 1974.

[1] Méndez Echenagucia, T., D. Pigram, A. Liew, T. Van Mele, and P. Block. Full-Scale Prototype of A CableNet and Fabric Formed Concrete Thin-Shell Roof. Paper presented at the 2018 IASS Symposium, 2018.

[7] Chilton, John, and Heinz Isler. Heinz Isler. London: Thomas Telford, 2000.

[2] Flügge, W. Stresses in Shells. Berlin: Springer Verlag, 1973.

[8] Lienhard, Julian, and Jan Knippers. “Bending-Active Structures. Form-Finding Strategies Using Elastic Deformation in Static and Kenetic Systems and the Structural Potentials Therein.” ITKE, Stuttgart, 2014.

[3] Adriaenssens, S., P. Block, D. Veenendaal, and C. Williams, Shell Structures for Architecture: Form Finding and Optimization, London: Routledge, 2014.

[4] Piker, D. “Kangaroo: Form Finding with Computational Physics.” Architectural Design 83, no. 2 (2013): 136-137.

[9] Siegel, C., Strukturformen der modernen Architektur: München: Callwey Verlag, 1960.

[5] Rippmann, M., L. Lachauer., and P. Block, “RhinoVAULT—Designing Funicular Form with Rhino”, computer software, 2012.

[10] Pini, V., J. Ruz, P. Kosaka, O. Malvar, M. Calleja, and J. Tamayo, “How Two-Dimensional Bending can Extraordinarily Stiffen Thin Sheets. ” Scientific Reports 6, Article number: 29627, 2016.

52

53

ROBOTIC FORCE PRINTING

EIGHT-LEGGED SHELL

PRELIMINARY GROUP WORKS

Reversed Force Field

Benjamin Carlton Hoyle (MIT) Weizhe Gao (Tongji)

5,500

Our goal was to create a structure that included overlapping elements. The resulting form has a number of thin legs and substantial material overhead, making for a canopy-like shell.

106

107

ROBOTIC FORCE PRINTING

EIGHT-LEGGED SHELL

PRELIMINARY GROUP WORKS

Reversed Force Field

Benjamin Carlton Hoyle (MIT) Weizhe Gao (Tongji)

5,500

Our goal was to create a structure that included overlapping elements. The resulting form has a number of thin legs and substantial material overhead, making for a canopy-like shell.

106

107

PRELIMINARY GROUP WORKS PRELIMINARY GROUP WORKS

ROBOTIC FORCE PRINTING ROBOTIC FORCE PRINTING SUBDIVISIONS SUBDIVISIONS Using Singly-Curved Strips to Emulate Double Curvature Using Singly-Curved Strips to Emulate Double Curvature Our subdivision scheme emulates double Our subdivision scheme emulates double curvature at the legs with two adjoining curvature at the legs with two adjoining strips and on the roof with three strips strips and on the roof with three strips

wrapping around an open triangle. Each wrapping around an open triangle. Each component of the model can be flattened. component of the model can be flattened.

110 62

TEST MODEL TEST MODEL We were able to print each element of We were able toin print each element of the subdivision 2d because they are thesingly subdivision 2D because are all all curvedinwhen erected.they For this singly curved when erected.

For this study study model we printed each strip with an model, we printed each strip with an

extruder-equipped robot arm. The mesh extruder-equipped mesh is loose, lending therobot final arm. form The a skeletal is loose, lending the final form a skeletal quality. quality.

63 111

PRELIMINARY GROUP WORKS PRELIMINARY GROUP WORKS

ROBOTIC FORCE PRINTING ROBOTIC FORCE PRINTING SUBDIVISIONS SUBDIVISIONS Using Singly-Curved Strips to Emulate Double Curvature Using Singly-Curved Strips to Emulate Double Curvature Our subdivision scheme emulates double Our subdivision scheme emulates double curvature at the legs with two adjoining curvature at the legs with two adjoining strips and on the roof with three strips strips and on the roof with three strips

wrapping around an open triangle. Each wrapping around an open triangle. Each component of the model can be flattened. component of the model can be flattened.

110 62

TEST MODEL TEST MODEL We were able to print each element of We were able toin print each element of the subdivision 2d because they are thesingly subdivision 2D because are all all curvedinwhen erected.they For this singly curved when erected.

For this study study model we printed each strip with an model, we printed each strip with an

extruder-equipped robot arm. The mesh extruder-equipped mesh is loose, lending therobot final arm. form The a skeletal is loose, lending the final form a skeletal quality. quality.

63 111

ROBOTIC FORCE PRINTING

WHITE HILL Weiran Zhu (Tongji) Hyerin Lee (MIT)

Drawing inspiration from the mountains of China, we created an undulating shell structure that swerves down in the middle. The shell also incorporates arched legs of different elevations to create a diverse experience for the user when walking through and around the

A Vault Formed

by Thrust Network Analysis

PRELIMINARY GROUP WORKS PRELIMINARY EXPLORATIONS We first explored various shapes and topologies to test their efficiency as well as aesthetics. At the end, we were interested in the undulating form created by a hole in the pavilion touching the ground partially.

The first form we found had much strength in its form due to the ample amount of double curvature. however, we decided to push the form a bit more and create greater openings as well as increase the span of the arches.

structure. It gains strength from its form found through thrust-network analysis using RhinoVAULT. Its double curvature, both anticlastic and synclastic, and the subsequent membrane action in the shell allows for high structural efficiency.

114

115

ROBOTIC FORCE PRINTING

WHITE HILL Weiran Zhu (Tongji) Hyerin Lee (MIT)

Drawing inspiration from the mountains of China, we created an undulating shell structure that swerves down in the middle. The shell also incorporates arched legs of different elevations to create a diverse experience for the user when walking through and around the

A Vault Formed

by Thrust Network Analysis

PRELIMINARY GROUP WORKS PRELIMINARY EXPLORATIONS We first explored various shapes and topologies to test their efficiency as well as aesthetics. At the end, we were interested in the undulating form created by a hole in the pavilion touching the ground partially.

The first form we found had much strength in its form due to the ample amount of double curvature. however, we decided to push the form a bit more and create greater openings as well as increase the span of the arches.

structure. It gains strength from its form found through thrust-network analysis using RhinoVAULT. Its double curvature, both anticlastic and synclastic, and the subsequent membrane action in the shell allows for high structural efficiency.

114

115

ROBOTIC FORCE PRINTING

PRELIMINARY GROUP WORKS

FABRICATION STRATEGY We first decided to dissect the structure into parts delineated by the quadrilaterals in the tessellation in order to planarize it. However, after we made

a model, we realized we would lose continuous curvature according to our method.

As our second strategy, we decided to planarize it following the strip lines. It proved to be a better strategy since long strips can bend and twist easily.

Then, each strip can be printed as layers of grids. put together, they would form a grid-shell structure.

The strips can be put together by bolting each layer together. and then the footing will be attached to a piece of board which can be bolted to the ground.

118

119

ROBOTIC FORCE PRINTING

PRELIMINARY GROUP WORKS

FABRICATION STRATEGY We first decided to dissect the structure into parts delineated by the quadrilaterals in the tessellation in order to planarize it. However, after we made

a model, we realized we would lose continuous curvature according to our method.

As our second strategy, we decided to planarize it following the strip lines. It proved to be a better strategy since long strips can bend and twist easily.

Then, each strip can be printed as layers of grids. put together, they would form a grid-shell structure.

The strips can be put together by bolting each layer together. and then the footing will be attached to a piece of board which can be bolted to the ground.

118

119

About ten years ago, Professor Stanford Anderson from Massachusetts Institute of Technology (MIT) initiated the joint workshop program with Tongji University in Shanghai and has continued his decade-long collaborations with Tongji since then, in which Chinese and American architects and architectural researchers were able to meet and exchange their ideas and researches. The Robotic Force Printing Workshop this year can be seen as a respectful tribute and continuity to such tradition.

Throughout the 23-day workshop, Philip F. Yuan, a professor of Tongji University and the founder of FabUnion Technology, who has achieved significant progress in the research and development of robotic construction equipment and processes will be in collaboration with Professor Philippe Block from ETH Zürich, an alumnus of MIT who has made outstanding achievements in the field of innovative structural design and construction over the last decade.

An intensive yet productive effort such as the Robotic Force Printing Workshop is only possible when the group has worked together firmly and collaboratively towards a common objective. In addition to the designfabrication studios, the workshop also consists of three field trips in association with one academic forum, four public lectures and a series of teaching modules on fundamental concepts of COMPAS and FURobotic to explore the integration between novel structural designs and the advances in additive manufacturing and robotic fabrication.

US $29.95 / UK £19.95