3D Shape Fabrication from Flat Material Sheets

Abstract

Digital fabrication has been a research area of huge interest in recent years, since it enables the fast creation of objects from digital models. Next to state-of-the-art technologies like 3D printing or more traditional CNC milling, techniques focused on flat materials are of interest, since modern laser cutters are fast and afford a large variety of cheap and durable materials, like plywood, acrylic glass or fabric. Previous methods for manufacturing from rigid flat sheets usually roughly approximate 3D objects by polyhedrons or cross sections and connecting, interlocking, or folding numerous laser cut panels. Not being limited to rigid material sheets, laser cutters are also an efficient way to cut pieces for garment production. Despite recent developments towards on-demand, individualized garment design and fabrication, the majority of processes in the fashion industry are still inefficient and heavily dependent on manual work. The standardized sizes used in the garment industry do not cover the range of individual differences in body shape for most people, leading to high return rates and overproduction. Consequently, recent research in this area has been focused on supporting designers to digitally create sewing patterns, shapes and on-demand individually fitting garments. In the first part of this thesis, we propose a radically different approach to approximate shapes with flat material sheets: Our approximation is based on cutting thin, planar spirals out of flat panels. When such spirals are pulled apart, they take on the shape of a 3D spring whose contours are similar to the input object. We devise an optimization problem that aims to minimize the number of required parts, thus reducing costs and fabrication time, while at the same time ensuring that the resulting spring mimics the shape of the original object. In addition to rapid fabrication and assembly, our method enables compact packaging and storage as flat parts. We also demonstrate its use for creating armatures for sculptures and moulds, with potential applications in architecture or construction. By approximating the human body, individualized tailor's dummies can also be fabricated. In the second part, we move on to study garments made from flat sewing patterns. So far, there has been little work on textured fabrics. Aligning textile patterns like stripes or plaid along garment seams requires an experienced tailor and is thus reserved only for expensive, high-end garments. In the second part of this thesis we therefore present an interactive algorithm for automatically aligning repetitive textile patterns along seams for a given garment, allowing a user to make design choices at each step of our pipeline. Our approach is based on the 17 wallpaper groups and the symmetries they exhibit. We exploit these symmetries to optimize the alignment of the sewing pattern with the textured fabric for each of its pieces, determining where to cut the fabric. We optionally alter the sewing pattern slightly for a perfect fit along seams, without visibly changing the 3D shape of the garment. The pieces can then be cut automatically by a CNC or laser cutter. Our approach fits within the pipeline of digital garment design, eliminating the difficult, manual step of aligning and cutting the garment pieces by hand. We extend our algorithm for pattern alignment to account for the global symmetries that underlie almost every sewing pattern due to the symmetry of the human body. We propose an interactive tool to define such symmetries and integrate them into the existing algorithm, such that both the texture alignment and the deformation of the sewing pattern adhere to these symmetries. In the third part, we propose an interactive design tool for creating custom-fit garments based 3D body scans of the intended wearer. Our method explicitly incorporates various body poses to ensure a better fit and freedom of movement. The core of our method focuses on tools to create a 3D garment shape directly on an avatar without an underlying sewing pattern and on the adjustment of that garment's rest shape while interpolating and moving through the different input poses. We alternate between cloth simulation steps and and the rest shape adjustment step based on stretch to achieve the final shape of the garment. At any step in the real-time process, we allow for interactive changes to the garment. Once the garment shape is finalized for production, established techniques can be used to parametrize it into a 2D sewing pattern or transform into a knitting pattern.