Conversion from 3D to 2D pattern algorithm for the 3D-shaped knitwear

Purpose The purpose of this paper is to develop the relationship among the three-dimensional-shaped (3D) knitwear on the flat knitting machine in a three-dimensional (3D) design model and the corresponding knitting in a two-dimensional (2D) pattern. Design/methodology/approach To do this, map functions are defined to convert the expression of the 3D-shaped knitwear to the horizontal and the vertical knitting. When the inverse functions of the map functions exist, one type is knitting in the 2D pattern can be determined with the aid of the knitwear expression in the 3D design model, when another type of knitting is in the 2D pattern. Findings The simulations indicate that the proposed scheme can implement the conversion from the 3D-shaped knitwear in the 3D design model to the corresponding knitting in the 2D pattern. In addition, the generated knitting by the proposed method can meet the technological requirements, which means that the knitting in the 2D pattern, converted by the proposed scheme, can be implemented in reality and the differences between the real knitwear can also be obtained as same as the map functions. Practical implications The generated 2D pattern can facilitate accelerating the design development of the 3D-shaped knitwear. Meanwhile, after accomplishing the 3D design, the relationship between 2D patterns in the two knitting directions is established through map functions. Originality/value Map functions proposed in this paper can be used in the 3D design model of the 3D-shaped knitwear so as to obtain the relatively accurate 2D paper appropriate for machine-knitting direction, which omits the process of designer's single 2D pattern after accomplishing the 3D design and saves the developing time.