Rethinking Prototyping

Design Modelling Symposium Berlin, 28/09 - 02/10/2013

Advisory Committee

Christoph Gengnagel, UdK Berlin

Axel Kilian, Princeton University

Julien Nembrini, UdK Berlin

Norbert Palz, UdK Berlin

Fabian Scheurer, designtoproduction, Zurich

Ioannis Zonitsas, Visual-Dream, Berlin

Organising Committee

Prof. Dr.-Ing. Christoph Gengnagel, UdK Berlin

Prof. Norbert Palz, UdK Berlin

Dagmar Rumpenhorst-Zonitsas, Daglicious Coordination

Scientific Committee

Sigrid Adriaenssens, Princeton University

Marc Alexa, TU Berlin

Jussi Ängeslevä, UdK Berlin

Olivier Bavarel, UR Navier, Université Paris-Est

Philippe Block, ETH Zürich

Alexander Bobenko, TU Berlin

Peter von Bülow, University of Michigan

Neil Burford, University of Dundee

Jeroen Coenders, TU Delft

Christian Derix, Aedas London

Günther Filz, Universität Innsbruck

Al Fisher, University of Bath

Christoph Gengnagel, UdK Berlin

Michael Hensel, Oslo School of Architecture and Design

Johann Habakuk Israel, Fraunhofer IPK Berlin

Axel Kilian, Princeton University

Toni Kotnik, ETH Zürich

Oliver Tessmann, KTH, Stockholm

Stefan Peters, TU Graz

Julian Lienhard, Universität Stuttgart

Julien Nembrini, UdK Berlin

Norbert Palz, UdK Berlin

Fabian Scheurer, designtoproduction Zurich

Volker Schmid, TU Berlin

Paul Shepherd, University of Bath

Martin Tamke, CITA Copenhagen

Florian Förster, Buro Happold Berlin

Roland Wüchner, TU München

Tobias Wallisser, ABK Stuttgart, LAVA Berlin

Main sponsor

Co-Sponsors

Contents

Foreword

Structural Design

Physical and Numerical Prototyping for Integrated Bending and Form-Active Textile Hybrid Structures

From Shape to Shell: A Design Tool to Materialise FreeForm Shapes Using Gridshell Structures

Designing Regular and Irregular Elastic Gridshells by Six DOF Dynamic Relaxation

Shaping Structural Systems

Bridging the Gap

Funicular Funnel Shells

From Structural Purity to Site Specificity New Canopies for the Entrance Gates of the Messe Frankfurt

Architectural Design

DesignScript: A Learning Environment for Design Computation

Frequencies of Wood – Designing in Abstract Domains

Enhancing Free-Form Architecture with Conical Panels

Embodied Prototypes: The Interaction of Material System and Environment

Combined Self-Organising Systems for Spatial Net Structures

A Framework for Flexible Search and Optimisation in Parametric Design

Operative Diagramatology: Structural Folding for Architectural Design

The Materiability Research

Ascending Curve - Digital Realisation of Shanghai Tower

MIKADOweb – Innovative Light-Weight Structure

Fuzzy Modelling with Self-Organising Maps

ALIVE - Designing with Aggregate Behaviour in Self-Aware Systems

Integrated Design Methods for the Simulation of Fibre-Based Structures

Complex Geometry

Behavioural Prototyping: An Approach to Agent-Based Computational Design Driven by Fabrication Characteristics and Material Constraints

From Generic to Specific - Prototyping a Computational Growth Model

Linear Folded V-shaped Stripes

Free-Form Shading and Lighting Systems from Planar Quads

Climate Design

Optimisation of the Building Skin Geometry to Maximise Solar Energy Collection

Analysing The Performance-Based Computational Design Process: A Data Study

Climate-Specific Mass-Customisation of Low-Technology Architecture as Part of a High-Technology Process

Digital Fabrication

Examples for Tool Integration in Design Concepts and Production Methods of Load Carrying Structures

Unlocking Robotic Design

Autonomous Tectonics - A Research into Emergent Robotic Construction Methods

Material Products: How Data is Successfully Transformed into Real-World Objects

The Design Carport – Prototyping Matter

Sketch-Based Pipeline for Mass Customisation

Prototyping

Prototyping Robotic Production: Development of Elastically-Bent Wood-Plate Morphologies with Curved Finger-Joint Seams

Design and Manufacturing of Self-Supporting Folded Structures Using Incremental Sheet Forming

Architectural “Making” Modes in Relation to Prototype Notions The Stripe Pavilion: Progression from a Bespoke to a Parametric-Algorithmic Mode

Blended Prototyping Design for Mobile Applications

Design Workflows for Digitally Calibrated Heterogenous Building Elements

Sustainability-Open: Why Every Building Will Be Sustainable in the Future

Prototyping Helixator

Validation Framework for Urban Mobility Product-Service Systems by Smart Hybrid Prototyping

Porsche Pavilion - Designing the World‘s Largest Seamless Monocoque Shell

The Generator 2.0

A Process where Performance Drives the Physical Design

Gradient Grid - A Spring Mesh with Different Zones of Flexibility

Serial and Persistent Prototyping Addressing Architectural Acoustics

Author Index

Foreword

Prototypical Models of Design

At this Symposium, we look forward to discussing the relationship between prototypes and models of design. The term

prototype

 stands for an implemented design step rather than a trial run for mass production, as an extension to the thought and computational constructs that make up the model of design. The term

models of design

 stands for the idea and all underlying abstractions and assumptions that define the design process.

The relation between model of design and prototype gains importance as our understanding and relating of material systems to their simulated abstract models improves and computation increasingly becomes embodied in physical constructs replacing complex mechanical assemblies with computational feedback and control.

In architecture, the mechanical complexity has usually been lower than in other engineering fields; but obviously much of architecture’s complexity lies in its cultural context and the human occupation due to its scale and the social density of the built environment. Buildings need to evolve due to their potential long lifespan and are essentially evolving prototypes of the initial design intent reflected in the design model. Bridging the gap between design abstraction during the design development and the operation of the built structure is an ongoing challenge. Inherent to the use of digital tools for design is a tension between using simulation and computational processes to develop robust physical constructs that work as physical assemblies but independent of their computational simulations, or whether to move the computational processes into the built form and further sophisticate the feedback and control cycles and adaptability of physical constructs. In other words, computational processes may be found at many levels whether implicitly as computationally crafted material behaviour and/or explicitly in the computational capabilities of construction elements.

In other engineering disciplines, one can see a fascinating trend where complex and large scale mechanical assemblies for mechanical control are replaced by simpler mechanics empowered by computational controls such as for instance in the case of the development of helicopters to quadcopters or windmills to autonomously flying power kites.

Architecture and engineering structures are obviously different from aerospace constructs in terms of development costs and impact on the physical environment, but similar effects may be achievable in enabling existing infrastructure and structure to operate beyond their initial design intent and capabilities. Already actuated structures responding computationally to live loads thus simpler or lighter than conventional ones are being developed and constructed. Even the average eco-building corresponds to the definition of a robot with complex control algorithms linking sensors to actuators. Imagining coordination and collaboration on a building-to-building scale as well as at the scale of cities, think of smart grids, is not inconceivable.

However fascinating, such developments implicitly entail further vulnerability to system failure. Structures losing their control capabilities may collapse; automatically-shaded

Passivehaus

 buildings overheat and become non-liveable. Directly embedding complex computational processes in the architecture calls for a careful balance between system performance and robustness.

Actually, long-going efforts in autonomous robotics suggest achieving robustness through embedding non-digital computational capabilities in physical constructs by exploiting system dynamics and non-linearities. Control only then provides the additional performance delta that makes the system reach the prescribed efficiency. Models, meaning our abstract understanding and invention of such processes play a crucial role in the development of new ideas and increasingly so as we rely more and more on their implementations in digital form.

We hope this collection of papers presents a range of insights at the cutting edge of the fields in addressing these questions and thank all participants for their contributions.

C. Gengnagel, University of the Arts, Berlin

A. Kilian, Princeton University, Princeton

J. Nembrini, University of the Arts, Berlin

Physical and Numerical Prototyping for Integrated Bending and Form-Active Textile Hybrid Structures

Sean Ahlquist, Julian Lienhardt, Jan Knippers and Achim Menges

1 Introduction

This paper describes research for the development and implementation of a functionally and structurally intricate textile hybrid architecture, entitled M1, built in Monthoiron, France as part of the La Tour de l’Architecte complex. The term textile hybrid stands for the mutual exchange of structural action between bending- and form-active systems based on textile material behaviour. The implementation of such a structural logic is critical to this particular project as its presence is minimally impactful to the site, which houses a historically protected, and decrepit stone tower from the fifteenth century’s, as shown in Fig.1. The design by Leonardo da Vinci employed an innovative buttressing system to structure the tower without a significant foundation. The buttresses have since been scavenged from the site, though the M1 structure seeks a minimal footprint to protect areas where traces of the original buttressing structure still exist.

To explore the complexities for minimal site imposition, lightweight material deployment and spatial differentiation, a set of multi-scalar and multi-modal prototyping procedures are developed. In both physical and numerical simulation, data towards eventual full-scale implementation is cumulatively compiled and calibrated, interleaving aspects of topology, material specification, force distribution and geometry. This paper defines prototyping as the interplay between modes of design in physical form-finding, approximated simulation through spring-based methods, and finite element analysis to form, articulate and materialise the textile hybrid structure. A particular feature in the exchange between and within these modes of design is the consideration of geometric input as a critical variable in the form-finding of bending-active behaviour.

Sean Ahlquist

University of Michigan, Taubman College of Architecture and Urban Planning, Ann Arbor, USA

Julian Lienhardt, Jan Knippers

University of Stuttgart, Institute for Building Structures and Structural Design, Stuttgart, Germany

Achim Menges

University of Stuttgart, Institute for Computational Design, Stuttgart, Germany

Fig. 1 Stone Tower and M1 Textile Hybrid at La Tour de l’Architecte, Monthoiron, France (Photos and drawings provided by Christian Armbruster, 2011; Ahlquist and Lienhard, 2012)

2 Multi-Hierarchical Textile Hybrid

The M1 textile hybrid project is formed via a multi-hierarchical arrangement of glass-fibre reinforced polymer (GFRP) rods of varying cross-sectional dimensions, which are structurally integrated with Polyester PVC membranes and polyamide-based textiles. The primary structure, in Fig. 2a, is formed of a series of interleaved loops emerging from only three foundations at the boundary. The meta-scale bending-active structure morphs between gridshell-like moments and free-spans stabilized by the tensile membranes. A secondary system (Fig. 2b) provides additional support through a series of interconnected cells embedded within the longest spanning region of the structure. Working to disintegrate the homogeneous nature of the textile membrane, the cells are differentiated in their form and orientation. The levels of hierarchy coalesce to form a clear span of up to eight meters with a total structure weighing only 60kg, while simultaneously generating variation in all scales of the spatial architecture.

Such articulation in behaviour and geometry is arrived at through an intricate exchange between various modes of form-finding. While the form-finding of tensile membrane structures considers stress harmoniously as an input variable, the form-finding of bending-active structures commonly results in varying stress distributions based on a comparatively large number of geometric and mechanical input variables. Therefore, the process of form-finding in the development of bending-active and, furthermore, textile hybrid structures eschews the consideration of structural optimisation. Aligning all input variables to form a functioning equilibrium, which satisfies both mechanical behaviour and contextual constraints, becomes the challenge within the form-finding processes and overall design framework. Due to this unique combination of freedom and complexity, it is shown through this research that a single computational technique alone does not offer the necessary flexibility and insight for developing textile hybrid structures. Rather, the combination and integration of multiple modes and techniques of design into a structured framework is shown to be necessary for the exploration and rationalization of complex textile hybrid structures.

Fig. 2 Multi-hierarchical textile hybrid system (Ahlquist and Lienhard, 2012)

These modes of design, in prototyping through form-finding, include physical models, spring-based computational studies and finite element analysis. Via physical experiments, specifications of topology and approximations of geometry are derived. Through spring-based modelling, also referred to as mass-spring methods or particle systems, variation is generated in the interactions between bending resistance and tensile forces (Ahlquist et al. 2013). In finite element analysis, fixed topological arrangements are inputs for exploration of specific mechanical relationships, force equilibria and further structural investigations (Lienhard et al. 2012). Each avenue serves to advance and articulate design aspects of the textile hybrid while also establishing the degree of fidelity towards the overall design framework.

3 Prototyping Framework for Textile Hybrid Systems

For designing a system formed of structural action, it can be decomposed into parameters of topology, structural forces, and materiality. Fig. 3 unravels these groups of parameters, as they would be addressed within a spring-based modelling and simulation environment. Topology specifies the count, type and associations of all elements within the system. Force describes the primary internal stresses, which the system will undergo, in this case tensile, compressive and bending actions. Materiality defines input parameters relevant to a material’s structural performance, while also translating values for computational or scaled behaviour into specific material definitions for fabrication and assembly. By distinguishing these parameters, particular relationships can be explored and exploited in their influence to material behaviour, as it forms force-active spatial architectures (Ahlquist and Menges 2011). This research describes the relationship between these aspects of material behaviour and relevant modes of design in physical form-finding, spring-based numerical methods, and simulation using finite element analysis.

3.1 Physical Form-Finding and Computational Means

While physical form-finding provides agile means for studying relationships of materiality and structural action within a single model, there is a limitation for any such study to predict behaviour beyond its own specific arrangement and scale. With a homogeneous material description, bending-active behaviour is generally scale-able as long as the topological input is repeated (Levien 2009). To establish a vehicle for design search, an individual study must serve as a prototypical case, projecting a design space, which implies a new vocabulary for form, performance and generative means (Coyne 1990). When integrating textile behaviour into a bending-active system, the extensibility of any one prototypical constructional model becomes further limited as the structural and spatial performance of the textile shifts greatly between scales.

While the physical prototype projects a narrow set of parametric rules and material descriptions, it can be a resource in defining fundamental logics of topology, proportion and behaviour, for further computational exploration. In this research, computational explorations occur through two venues: modelling and simulation of relative material descriptions with spring-based numerical methods, and finite element analysis defining precise mechanical (material and force) relationships. Spring-based methods calculate force based upon linear elastic stress-strain relationships (Hooke’s Law of Elasticity); using a numerical integration method such as Euler or Runge-Kutta to approximate the equilibrium of multiple interconnected springs (Kilian and Oschendorf 2005). Such methods are deployed to primarily explore varied relationships between topology and force. Both conditions are easily manipulable during the process of spring-based form-finding, enabling immediacy for fe