Research On Surface Unfolding And Layout Algorithm Of Warp Knitted Uppers

Warp knitted jacquard uppers are widely used in sports shoes because of their good air permeability.In the process of materializing the finished product of warp knitted jacquard sports shoes,it is necessary to get the plane expansion diagram of 3D shoe upper if you want to get the complete material size,the design of shoe upper fabric color and the reasonable layout scheme in actual production.In this paper,an algorithm for two-dimensional expansion of warp knitted jacquard uppers is studied,and the design and simulation of jacquard pattern are carried out by using the profile of the uppers after expansion,and the effectiveness of the algorithm is verified.Single unrolled uppers after the completion of the design simulation,the design of the design of the carpenter diagram typesetting,get the final machine knitting diagram.The 3D model of warp knitting jacquard vamp is triangulated and the data structure which fits the unfolding algorithm is constructed.According to the geometric features of the upper and the shape of the upper commonly used in typesetting,the cutting line of the upper is selected based on the search of the inner and outer boundary to ensure the feasibility of the subsequent algorithm process.Then,because of the need to reduce the error as much as possible,a search method for the center triangle of the shoe upper of the triangulated mesh(i.e.the first unrolled triangle)is proposed.In this paper,a method for calculating the expansion of a single space triangle based on Euclidean distance is presented.The various situations of the vertex to be solved during the expansion of a single triangle are listed.The central triangle is distinguished from the ordinary triangle,and the detailed calculation method for the two-dimensional coordinates of the vertex to be solved is given.Finally,the initial unfolding of the whole uppers is realized and the corresponding results are obtained.There are some undesirable phenomena such as uneven distribution of triangulated mesh in the initial unrolled upper.Therefore,the principle of mass-spring model is used to optimize the initial expansion results.By calculating the mass,acceleration,velocity and position of each particle on the vamp,a prime-spring strain energy model suitable for triangulating mesh vamp is established.How to adjust the increment value of unit time according to the result of each iteration is given.Finally,the optimized unfolding result is obtained.According to the profile of the unfolding uppers,the jacquard design and simulation are carried out,and the texture of the two-dimensional uppers fabric is mapped to the three-dimensional uppers,and the position of the designed pattern in the three-dimensional uppers is correct and the deformation is small to verify the effectiveness of the unfolding algorithm.The uppers are directly used in production as knitting units,which will cause waste of raw materials.In production practice,the uppers need to be compact arranged on the fabric surface to improve production efficiency and reduce costs.The rapid typesetting method and the maximization of shoe material utilization were studied in this paper.Three common typesetting methods of warp knitted jacquard uppers are presented,and the material utilization rate of warp knitted jacquard uppers is calculated.In order to place the upper quickly and reasonably,the area and boundary of the upper are extracted,and the specific flow of the arrangement of the upper is obtained.Finally,the layout algorithm is implemented through boundary collision detection.According to the parallel characteristics of the typesetting algorithm,CUDA was used to achieve the final implementation effect.This algorithm realized the speed and automation of the upper typesetting,and the reasonable placement of the upper position also improved the fabric utilization.