Computer modelling for garment pattern design.

摘要

Mass customization is a vision to be attempted. Achievement of this vision depends on three crucial processes: (1) body scanning, (2) pattern unfolding, and (3) visualization of the test trial in the virtual reality. This piece of research work is dedicated to the pattern unfolding process. The researcher attempted to build a mathematical model of such activities, so that computerization could be accomplished.;The first step towards such modelling was to study the operational aspect of the pattern making activity. A semigroup structure was identified. The Abelian Pattern Semigroup P was defined on a set of surface area, together with the binary assembly operation.;Next, a variational model of the human body was designed. Linear measurements, such as the girth measurement of the chest, were converted into shape parameters and stick parameters, which controlled the cross-sectional shape.;The first order approximation of the Algebraic Mannequin consisted of a collection of bicubic tensor product Bezier surface patches. The horizontal boundary curves were the cross-sectional curves, while the vertical boundary curves were constructed to satisfy the ;Based on the Algebraic Mannequin, the pattern unfolding process was a bijective mapping between the 3D surface patches of P;After the key reference points were mapped, a set of 4-sided approximation patches were formed. The last stage of the unfolding process was to reconstruct the boundaries by smoothing out the lines connecting the data points.;The distortion property in distance under the Bijective Pattern Map was studied with respect to the Gaussian curvature of the surface. The examples were drawn from the surface patches of the Algebraic Mannequin. The distortion was acceptable when the surface was relatively flat.;More important, several indices were defined for measuring the static fit of a garment. The signature curve was defined on the in-between cross-sectional area with respect to the height. Hence, the design of the pattern with a given fit could be solved, using this signature curve approach.;This research project has made the following contribution: (1) Reveal the mathematical aspect of the pattern design process, which has been regarded as an art of craftsmanship. (2) Offer an alternative computer model of Pattern Draping. (3) Incorporate industrial knowledge into a variational model for describing the 3D human body. (4) Unify the framework of surface unfolding and pattern projection. (5) Design methods to measure the "fit" of a garment objectively. (6) Solve the design problem of reconstructing a garment for any given "fit".