Selected Examples for the Optimization of Cutting Patterns for Textile Membranes

The cutting patterning is an essential part of the engineering process in textile architecture. In the past it was very costly and time-intensive if the waste of material was to be minimized. Nowadays we have fast or even automatic patterning tools where those problems are solved efficiently as we are willing to show in this paper. In a short introduction we present different flattening theories, the meaning of geodesic lines in this context, the definition of constraints as angles and distances, and the final estimation of the quality of the patterning by numbers. Then the preparation of the cutting patterns for the production is shown briefly as e.g. seam allowances, welding-marks, etc. But patterning is not only a in the responsibility of the membrane-engineer, the architects are using the seamlines as an important factor in the design of lightweight architecture. We support it with our software by so-called hierarchical cuts, by a fast extension of seam-lines in the neighbormembrane-fields (to avoid staggered lines), etc. Then we put the focus on procedures with respect to selected examples where cutting patterns are calculated and optimized efficiently. The optimization is almost always related to the waste of material. The widths of the patterns should be a maximum with respect to the rolewidth of the material by considering the quality of the patterns. Starting from a small four-point-sail we describe precisely the process chain. Then we show the automatic patterning generation of a high point membrane and a big air-hall