###### Abstract  
It has become clear over the last decade that the building industry must rapidly change to meet globally pressing requirements. The strong links between climate change and the environmental impact of architecture mean an urgent necessity for alternative design solutions. In order to propose them in this project, two emergent fabrication techniques were deployed with natural fiber-reinforced polymers (NFRPs), namely tailored fiber placement (TFP) and coreless filament winding (CFW). The approach is explored through the design and prototyping of a stool, as an analogue of the functional and structural performance requirements of an architectural system. TFP and CFW technologies are leveraged for their abilities of strategic material placement to create high-performance differentiated structure and geometry. Flax fibers, in this case, provide a renewable alternative for high-performance yarns, such as carbon, glass, or basalt. The novel contribution of this project is exploring the use of a TFP preform as an embedded fabrication frame for CFW. This eliminates the complex, expensive, and rigid holds that are traditionally associated with composites. Through a bottom-up iterative method, material and structure are explored in an integrative design process. This culminates in a lightweight FlexFlax Stool design (ca. 1 kg), which can carry approximately 80 times its weight, articulated in a new material-based design tectonic. natural fiber-reinforced polymers; NFRP; computational design; tailored fiber placement; coreless filament winding; rapid prototyping; industry 4.0; lightweight structure +
Footnote †: journal: Applied Soft  
top-down manner. This is not a new problem, nor is it trivial, and there are a number of attitudes for using materials more responsibly. Some strategies come from incremental technological development, whilst others adopt techniques, technologies, and ideas from other industries, opening the door to new possibilities [4]. It is appropriate, then, to investigate how these alternative approaches may translate into more harmonious architectural design solutions. Fiber-reinforced composites (FRCs) have been well used in the automotive, nautical, and aerospace industries over the last decades, but less so in architecture and product design. In contrast to some other processes, working with composites can allow for the strategic placement of material to create differentiated structure and geometry. This is typically done in an additive process and can result in products with a high specific strength. A superior strength-to-weight ratio can, in turn, translate into reduced material use, as well as reduced use of supporting materials, such as concrete or metals [5]. Two particularly novel composite fabrication methods for FRCs are coreless filament winding (CFW) and tailored fiber placement (TFP). Both processes have great potential at the architectural scale. These techniques deploy numerically-controlled machines in digital design workflows for precision, efficiency, and mass-customization [6; 7]. However, both CFW and TFP still used complicated and resource-intensive fabrication frames or molds during production (Figure 1). For almost 10 years, the Institute for Computational Design (ICD), the Institute of Building Structures and Structural Design (ITKE), and, more recently, the BioMat group at ITKE (the Department of Biobased Materials and Materials Cycles in Architecture) at the University of Stuttgart, have investigated composites through the lenses of computation, digital design and fabrication, structure, and sustainability. Their research has not been limited to conventional FRC based on carbon fibers (CFs) and glass fibers (GFs), but also explored possibilities of replacing them with fibers from annually renewable resources, such as flax and hemp, as well as with agricultural residues, namely straw, for the purpose of developing structural systems based on natural fiber-reinforced polymers (NFRPs) [8].