String-Actuated Curved Folded Surfaces

Curved folded surfaces, given their ability to produce elegant freeform shapes by folding flat sheets etched with curved creases, hold a special place in computational Origami. Artists and designers have proposed a wide variety of different fold patterns to create a range of interesting surfaces. The creative process, design, as well as fabrication is usually only concerned with the static surface that emerges once folding has completed. Folding such patterns, however, is difficult as multiple creases have to be folded simultaneously to obtain a properly folded target shape. We introduce string actuated curved folded surfaces that can be shaped by pulling a network of strings, thus, vastly simplifying the process of creating such surfaces and making the folding motion an integral part of the design. Technically, we solve the problem of which surface points to string together and how to actuate them by locally expressing a desired folding path in the space of isometric shape deformations in terms of novel string actuation modes. We demonstrate the validity of our approach by computing string actuation networks for a range of well-known crease patterns and testing their effectiveness on physical prototypes. All the examples in this article can be downloaded for personal use from http://geometry.cs.ucl.ac.uk/projects/2017/string-actuated/

Computational Design and Construction of Notch-Free Reciprocal Frame Structures

International audienceA reciprocal frame (RF) is a self-standing 3D structure typically formed by a complex grillage created as an assembly of simple atomic RF-units, which are in turn made up of three or more sloping rods forming individual units. While RF-structures are attractive given their simplicity, beauty, and ease of deployment; creating such structures, however, is difficult and cumbersome. In this work, we present an interactive computational framework for designing and assembling RF-structures around a 3D reference surface. Targeting notch-free assemblies, wherein individual rods or sticks are simply tied together, we focus on simplifying both the process of exploring the space of aesthetic designs and also the actual assembly process. By providing computational support to simplify the design and assembly process, our tool enables novice users to interactivity explore a range of design variations, and assists them to construct the final RF-structure design. We use the proposed framework to design a range of RF-structures of varying complexity and also physically construct a selection of the models. Figure 1: Physical RF-structures designed and fabricated by architects: a simple roof structure (top-left), a design by Michael Clarke (top-right), a design from Spiro-ETH (bottom-left), and a design from Wan Shu and Kengo Kuma (bottom-right)

Generative Reciprocity: A Computational Approach for Performance-Based and Fabrication-Aware Design of Reciprocal Systems

Using the capabilities of computation and digital fabrication this thesis provides a basis for a novel process of design to fabrication for reciprocal systems. In the traditional sense, reciprocal structures combine the advantages of timber as a renewable source of construction material and low-energy production with the modular fabrication, fabrication efficiency, structural capacities, and elegance of reciprocal interconnection of members. The unique benefits of reciprocal systems come from their discrete geometry, which simplifies the connection detailing and provides freedom for local and global variations in the system. However, this reduction in construction complexity and flexibility of local variation is replaced with geometrical complexity due to numerous compatibility constraints coupled with the structural behavior of the system. This research therefore identifies the key design parameters and design constraints of reciprocal systems. The results demonstrate the complex coupling of geometry, structural performance and fabrication in these systems, hence an essential need for application of an integrative design process. Through the application of computation, simulation, and digital fabrication this research proposes an integrative computational design process which can effectively address the coupling of design, analysis and fabrication of reciprocal systems and accommodate design exploration and optimization. First, a novel computational method for geometric modelling and form-finding is presented to resolve the compatibility constraints and generate the essential geometric and topological data for analysis and fabrication. Second, a flexible and scalable analysis method is implemented to study the interplay of the design parameters and the structural behavior of reciprocal systems. A comprehensive parametric study reveals a complex relationship between the geometric parameters and the structural performance and demonstrates the essential need for a real-time performance feedback for optimal design of free-form reciprocal systems. Third, a generalizable and efficient fabrication process is proposed for reciprocal systems with 3-D module geometry using 5-axis CNC machinery. Towards this goal, four different connection types are proposed, and different fabrication parameters are studied through digital and physical prototyping, destructive structural testing, detailed finite element simulation, and fabrication of a scaled structure. The results are summarized as a guideline for selection of the main fabrication parameters including joint detailing and fabrication tolerances. The computational design process is then developed by rethinking and replacing the conventional direct incremental development by a modular integrative computational process using multi-directional dataflow between different design phases. Finally, the proposed framework is used for a full-scale design to fabrication case study to validate the applicability of the proposed design process.PHDArchitectureUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/155121/1/oliyan_1.pd