Customization of shoe last based on 3D design process with adjustable 3D ease allowance for better comfort and design

The shoe last is an essential element because the style, fit and comfort of a shoe depend on its design, shape and volume. The shape of the shoe last is essentially linked to the dimensions of the foot to ensure comfort and good development of the foot for a chosen style. Therefore, a functional analysis of the shoe last is crucial critical to better understand the specificities of each zone. The goal of our current research is to determine the 3D ease allowance between the foot and the shoe last to customize the shoe last. The research was conducted through a 3D design process in a virtual environment. The research begins with a detailed understanding of the general characteristics of the shoe last based on anthropometric line and curves. Later, the planter foot surface for both lower and upper last of the shoe is developed based on the 3D method using the 3D design concept software, which is very similar to the 2D graphic method. To understand how 3D comfort is distributed between the lasts and the foot, the space between the foot and the last is analysed by a reverse procedure in 3D shapes. In the shoe last customization process, both the rear and front foot surface parts were further modelled, and the 3D ease allowance was determined based on a 3D graphical process. The developed customized last model was then accessed not only with good foot surface coverage but also with 3D ease analysis in the virtual environment. The results show that the ease allowance is evenly distributed on the surface of the foot and contributed to the conditions of comfort and blocking of the foot in the shoe. The proposed design process could help designers, developers and the footwear industry to design and develop a customized shoe last with adjustable ease allowance.