Modeling and deformation simulation of weft knitted fabric at yarn level

This study proposes a method for 3D modeling of weft knitted fabric and simulating its deformation behavior. A geometric model of the fabric was established using a loop-mesh unit, and the surface of the yarn was calculated using a reference frame. The patterns of the fabrics were represented by bitmap images. To simulate the deformation behavior of the fabric, a physical model was built based on a dynamic spline that included stretching and bending of the yarn. To simplify the collisions between continuous yarns, collisions were detected using a discrete sphere-spring model. The Euler-Lagrange theorem was introduced to achieve the energy balance of the system, and a stable shape was obtained by solving the Euler-Lagrange equation explicitly according to the convergence conditions. Rendering and deformation of the model were implemented using a simulator program via C++ and OpenGL. The simulation displayed the 3D appearance of the weft knitted fabric. The deformed shapes of fabrics were accurately predicted by the proposed method.