In the apparel industry, pattern making and alterations are expensive and time consuming, because they require iterative fitting and adjustment to develop garment patterns that fit their target consumers. The goal of this paper is to accelerate the pattern making process for jeans customization, which incorporates proper ease distribution at crotch curve in a 3D jeans design and pattern alteration by developing ease distribution models. In this research, four female jeans with different crotch ease allowances were developed. The patterns were drafted using flat patterning methods. The fitting process was conducted and evaluated according to standard fitting criteria. Furthermore, the size 8 mannequin, and then the jeans with the mannequin inside were scanned by the Kinect Body Image System. The crotch curves of the mannequin and the jeans were obtained, and were then extracted to the Accumark CAD system where the radial distance eases of the crotch curves were defined and measured. Correlation analysis between the distance ease and crotch ease allowance was conducted, and regression analysis was used to develop ease distribution models. The applications of the regression models in 3D jeans design and jeans pattern alterations were discussed. This research enhances the understanding of the ease distribution at the jeans crotch area. The results of this research provide essential ease distribution information for the jeans pattern alterations and jeans construction on a 3D model. / text