PurposeThis paper aims to present a flattening method for developing 2D basic patterns from 3D designed garments. The method incorporates the techniques of professional pattern development for the purpose of pattern‐making automation. The aims of the flattening method are to improve the dressing suitability and to produce pleasing figures by reversing design procedures.Design/methodology/approachA flattening method is presented in this paper for developing 3D undevelopable NURBS surfaces in 2D. The automatic operation embeds the expertise of pattern makers by reducing total area differences between the designed garments in 3D styles and the two‐dimensional patterns. Basic pattern‐making invokes the boundary constraints which apply mesh alignments techniques.FindingsThe global area difference between the original 3D designs and the 2D‐developed pattern is controlled within 5 percent in order to reach the final outcomes of basic patterns, whose shapes are similar to the drawing patterns currently utilized in the industry.Research limitations/implicationsThis study currently handles simple designs, such as basal designs, and can only flatten garments in symmetric styles. The direct flattening method is developed by this study. In addition, this study is supplemented by expert‐based knowledge, and it establishes basic boundary conditions for various garment patterns to increase the feasibility of flattening automation.Originality/valueThis study introduces the fundamental theories and methodologies used in the automatic making of basic patterns from 3D garment designs. It proposes a flattening method with pattern expertise embedded by real‐time approximations of the global area of the 3D undevelopable designs to the 2D patterns.

PurposeBased on the knowledge of professional pattern makers, this paper aims to propose an expert‐based automation technique of darts generation by aligning and drawing close meshes in basic pattern in Part I. Single dart development, such as waist‐fitting dart, shoulder dart, armscye dart, side dart, and their select combination are also presented.Design/methodology/approachIn this paper, 3D garment surface is first approximated by a finite number of meshes. Patterns are developed by aligning and rotating of the flattened meshes under the constraint of overlay avoidance. The envelop areas between the developed patterns and the curved surface are dramatically reduced from 5 percent of basic pattern to below 3 percent after darts development.FindingsThe development patterns are varied in their association with the subject's body figures and the designed garment. Darts in a different location can reduce the total area difference between the flattening undevelopable surface and the original curved surface.Research limitations/implicationsAt the present stage the pattern development method cannot guarantee the uniqueness of pattern outline. Moreover, the pattern maker's knowledge inputs in this paper can only apply to the subject whose waist girth is less than hip girth in circumference.Originality/valueThe embedded pattern maker knowledge provides certain rules for pattern development from 3D design. Moreover, it is practical to be used and exported to modern 2D pattern software for further editing and revision. The same person is also used as a model after the patterns have been sewn into clothes.

Purpose – The purpose of this paper is to find the pattern with minimal deformation energy while developing from 3D designed garments. Moreover, darts are generated to further reduce deformation energy. The aims of the energy-based flattening method are to reduce the difference between 3D designed garments and 2D flattened patterns in an accurate and efficient way. Design/methodology/approach – This study uses a mass spring method and iterative optimization to analyze pattern contours with minimal contour deformation while flattening three dimensional draping designs into a plane. Darts are generated to further reduce distortion during surface flattening and the energy method is introduced to verify that the analysis results obtained match the garment darts provided by the Bunka formula which is currently widely used in East Asia. Findings – An efficient method for generating optimal darted pattern is presented. It compares the important factors of darts, including position, length and amount. After iterative optimization and darts generation, the maximum energy reduction is about 30 percent. Originality/value – This study provides an aggregate to analyze and compare the differences between different patterns and conduct a verification comparison with traditional pattern formula.

Distortions are inevitable when flattening is applied to an irregular surface. This study presents a meshing energy model and evaluates the energy variation between the 3D designed surface and the 2D flattened pattern in order to minimize the energy that arises from the development process. Base on expert knowledge, constraint optimization methods are used to find the unique pattern in its minimum deformation. This method is applied via simulation to some garment examples. Taking design and manufacturing conditions into consideration, the designed garments are flattened into patterns which have the least energy and area variation from the 3D designs.