For designers of large products such as boats, cars and houses, there have been few cost-effective machines or methods in support of one-to-one, large-scale physical prototyping. A novel physical production system is demonstrated, aiming at rapid prototyping of large-scale models. Research questions address possible ways that the system can support design prototyping as opposed to manufacturing. We present computational methods used to generate model data, principle of decomposition of a large model, and assembly of components to form 3D prototypes. The process of model making in this study revealed an extended use of human body. Our view on embodied cognition in relation to the development of the large-scale rapid prototyping system is discussed. We end with a projection of new possibilities for large-scale prototyping that engages the human body.

A rapid prototyping method is invented, which works on a specific data structure produced by an optical metrology technique: 360-degree surface profile scanning. A computer algorithm takes an object profile data, restructure the format, generate horizontal and vertical ribs, lay out the ribs on a 2D canvas and output the geometries to a file format compatible with laser cutters. A laser cutting machine is subsequently used to cut all the ribs from sheet materials. Then, the ribs are manually assembled based on computer-generated assembly codes. Through this process, the original object's 3D surface can be prototyped rapidly at an arbitrary scale, which may well exceed the working dimension of the laser cutter. IntroductionRapid prototyping technologies, such as 3D printing and laser cutting, have been rapidly developed for years. New applications and cross-disciplinary research ideas emerge along with the maturity of the technology [1]. In this trend, the interaction between engineering and architecture plays a distinctively important role. Such interactions are especially nurtured and cherished at Singapore University of Technology and Design (SUTD), a recently established government institution in collaboration with Massachusetts Institute of Technology (MIT).The conventional notion of rapid prototyping is a non-scalable method of physical design production. Designers are limited to model manufacturing as small, desktop artifacts reduced in sized by factors. A typical maximum model size when using common rapid prototyping machines is less than 25 centimeters square. This is due to the physical limitation of the machine's building method. Software generates data assuming that production is of a single model limited to the build volume of the machine. Research exploration in the field has yet to produce a reliable, cost effective method of prototyping or mass manufacturing of very large objects.In this paper, we introduce a project funded by the International Design Center (IDC) of SUTD. Our objective is to explore a "very large scale prototyping" technique to extend the physical limit of a laser cutter. This technique takes the optically measured surface profile of an object as the input and automatically generates a very large scale surface skeleton structure as the output. The structure is composed of many "ribs" that can be manufactured by a commercial laser cutter. Each rib has a number of slots to enable assembly with adjacent ribs by simple interlocking mechanism. At the end of the processing pipeline, a reverse engineered prototype of the original object can be produced efficiently. Reconstruction of surface profileAn optical metrology method is applied to obtain an object 360-degree surface profile. The experimental setup is shown in Figure 1. The projector projects a black-and-white light field with a sharp edge. The light

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