We developed a three-dimensional apparel CAD system which simulated sample making and draping processes. In this paper, we explain the sample making system. Using this system, we can predict the shape of garment without actually making and fitting it. The basic idea for the system is that the natural shapes of garments are determined by four main factors, namely, mechanical properties of material fabrics, geometrical and topological shapes of paper patterns, shape of the human body and the way of dressing. The predicted shape of a garment changes according to these four factors. For example, there is some difference between the same pattern worn by different persons. Here we focus on the mechanical formulation of paper patterns and garments. To formulate them, we use the finite difference energy method which is one of the finite element discretization procedures. In terms of structure analysis, to predict the shape of garments is a large deformation and contact problem. To solve the large deformation problem, total Lagrangian formulation is employed in which 2nd Piola-Kirchhoff stress and Green-Lagrange strain are used. As for the contact problem, the existence of the human body is interpreted as a constraint condition. So, we describe the formulation of body surface. Finally we give some examples to show that this system is applicable to a wide range of garments.
